摘要:

ANNUAL REPORTSON THEPROGRESS OF CHEMISTRYANNUAL REPORTSON THEPROGRESS OF CHEMISTRYF O R 1 9 2 7 .ISSUED BY THE CHEMICAL SOCIETY.dLornmiftee o f @ubIictrfion :Chairman : N. V. SIDGWICK, M.A., Sc.D., F. R.S.M. P. AYPLEBEY, M.A., B.Sc.H. B. BAKER, C.B.E., D.Sc., F.B.S.H. BASSETT, D.Sc., Ph.D.H. V. A. RRISCOE, D.Sc.I!’. G. DONNAN, C.B.E., M.A., F.R.S.H. W. DUDLEY, O.B.E., M.Sc., P11.D.U. It. EVAXS, M.A.J. J. Fox, O.B.E., D.Sc.C. S. GIBSON, O.B.E., M.A.R. JV. GRAY, O.B.E., Ph.D.A. J. GREENAWAY, P.I.C.T. A. HENRP, D.Sc.C. I<. INGOLD, D.Sc., F.R.P.&hifor :CLAREKCE SMITH, I).&.J. KKNYON, D.Sc.H. KING, D.Sc.H. MCCOMBIE, D.S.O., M.C., D.Sc.T. S. MOORE, M.A., 13.S~.G. T. MORGAN, O.B.E., ll.Sc., F.R.S.I<. J. P.OHTON, M.A., F.R.S.J. R. PARTINGTON, M.B.E., D.Sc.J. C. PHILIP, O.B.E., D.Sc,, F.R.S.T. S. PRICE, O.B.E., D.Sc., F.R.S.F. L. PYMAN, D.Sc., F.R.S.E. K. RIDEAL, M.A., Ph.D.R. ROBINSON, D.Sc., F.R.S.J. F. THORPE, C.B.E., D.Sc., F.R.S.~!ssisfrrnt &%tar :A. D. MITCHELL, D.Sc.3iub.exar :MARGARET LE PLA, B.Sc.A. J. BRADLEY, Ph.D.€I. V. A. BRISCOE, D.Sc.B. A. ELLIS, M.A.J. J. Pox, O.B.E., D.Sc.C. T. GIBIINGHAM, O.B.E., R.Sc.W. N. HAWORTH, D.Sc., Ph.D.T. A. HENRY, D.Sc. c. N. HINSHELWOOD, n f . ~ .danfribiit urs : i H. HUNTER, D.Sc.1 J. PRSDE, KSc.C. K. INGOLD, D.Sc., F.R.S.It. W. JAMES, M.A.P. L. ROBINSON. D.Sc. I L.J. SPENCER, M.A., Sc.D.,F.R.S. 1 J. WEST, MAC.Vol. XXIV.LQNDON :GURNEY & J A C K S O N , 33 PATERNOSTER ROW, E.C.4.1928PRINTED IN QREAT BRITAIN BYRICHARD CLAY & SONS LIMITED.BUNQAY, YUFFOLKCONTENTS.PAGEGENERAL AND PHYSICAL CHEMISTRY.By H. HUNTER, D.Sc. . 11INORGANIC CHEMISTRY. By H. V. A. BRISCOE, D.Sc., and P. L.RODIKSON, D.Sc. . . . . . . . . . 37ORGANIC CHEMISTRY :-Part ~.-ALIPHATIC DIVISION. By W. N. HAWORTH, D.Sc., Ph.D. . 61Part II.-HOMOCYCLIC DIVISION. By C. K. INGOLD, D.Sc., F.R.S. . 106Part III.--IIETEROCPCLIC DIVISION. By T. A. HENRY, D.Sc. . . 158ANALYTICAL CHENISTRP. By J. J. FOX, O.B.E., D.Sc., and B. A.ELLIS, M.A. . . . . . . . . . . 196BIOCHEMISTRY. By C. T. GIMINGHAM, O.B.E., B.Sc., and J. PRYDE,M.s~. . . . . . . . . . . . 218CRYSTALLOGRAPHY. By R. W. JAMES, M.A., J. WEST, M.Sc., andA. J. BRADLEY, Ph.D.. . . . . . . . 273MINERALOGICAL CHEMISTRY (1926-7). Ey L. J. SPEX’CEK, M.A.,Sc.D., F.R.S. . . . . . . . . . . 292CHEMICAL KINETICS. By C. N. HIRSHELWOOD, &LA. . . . 31Abbrez.iatcd Title.A . , . . . .A . . . . . .Acta Phytochinz . . .Acta Sci. Fennicae . .Amer. Chem J. . . .Amer. J. Bot. . , .Amner. J. Pharnz. . .Amer. J. Phylsiol. . .Amer. J. Sci. . . .Ainer. Mia. . . .Anal. Asoc. Quim ArgentinnAn.al. Fis. Quim. . .Anajyst . . . .Annalen . . . .Ann. Acad. Sci. Feiznicne .Ann. Appl. Biol. . .Ann. Bot. . . . .Ann. Chim. . . .Ann. C7bim. anal. . .Ann. Chim. Appl. . .Ann. PJiysilc . . .Ann. Physique . . .Ann. Reports . , .Ann. Bep. Appt. C7~enz. .Bnn. Keportu Roth. Exp.Sta. . . . .Ann. Sci. Univ.Jcmy .Ann. SOC. yio‘ol. Bclg. . .Arch. exp. Path. Phnrm. .Arch. Farm. sperim. Sci.a$.. . . . .Arch. Phnrm. . . .drsbok Sveriges CTeol. Unders.Atti .R. Accad. Lincei . ,B . . . . . ,Rer. . , . , .Bied. Zentlalbi. . . .Hiocliem. J. . . .Bioehem. 2. . . .REFERENCES,TABLE OF ABBREVIATIONS EMPLOYED IN THE,The year is not inserted in references t o 1927.FULL TITLE.Abstracts in Journal of the Chemical Society.British Chemical Abstracts,* Section A.Acta P hytochimica .Acta Societatis Scientiarum Fennicae.American Chemical Journal.American Journal of Botany.American Journal of Pharinacy.American Journal of Physiology.American Journal of Science,American Mineralogist.Anales d e la Asociacion Quimica Argentina.Anales de la Sociedad Espanala Fisica y Quimica.The Analyst.Justus Liebig’s Annalen der Chemie.Amales Academia Scicntiarum Fennicae.Annals of Applied Biology.Annals of Botany.Annales de Chimie.Anna1t.s de Chiniie analy tique appliquQe a l’hduutrie,B I’Agiculture,Annali di Chirnica Applicata.Annalen der Pliysik.Annales de Physique.Annual Reports of the Chemical Society.Annual Reports 011 the Progress of Applied Chemistry.Annual Reports of the Rothamsted ExperimentalAnnales scientiiiques de 1’Universitd de Jassy.Annales de la SociQt6 gQologique de Belgique [in-Archiv fur experimentelle Pathologie und Pharnia-Archivio di Farmacologia sperimentale e ScienzeArchiv der Pharmazie.Sveriges Geologiska UnderEokning, Arsbok, Stock-holm.Atti (Kendiconti, Memorie) della Reale AccademisNazionale dei Lincei, classe di scienze fisiche,matematiche e naturali, Rorna.British Cherriical Abstracts,* Section B.Berichte der Deutschen Chemischen Gesellschaft.Biedermann’s Zmtral blatt.The Siocheniical Journal.Biochemische Zeitschrift.la l’harmacie et A la Riologie.Station.cluding Mem.and B d l . ] , LiBge.kologie.afflniTABLE OB ABBREVIATIONS EMPLOYED IN THE REFERENCES. viiAbbreviatdd Title.Biol. Zentralbl. , . .Bol. A c d . Nac. C&vtcicC.p,Cdrdoba . . . .Bob. Gaz, . . . .Brit. Assoe. Repwts . .Bul. SOC. chim. Romdnia .Bul, Soc. Romdna Stiinte .Bull. Acad. roy. Belg. .Bull. Chem. Soc. Japan .Bull. int. Acnd. Polorwise .Bull. Soc. chim. .Bull. SOC. chim.Belg.Bull. SOC. Chim. b i d .Bull. Xoc. fmng. Min.Centr. dlin. . .Chem. and Ind. . .Chem. Listy . .Chem. Met. h'ltg. .Chem. News . .Chem. Umschau . .Chm. Weekblad .Chem. Ztg. . .Cim. . . . .Coinpt. rend. . .Dcp. Agr. Union S. Afr.Sci. Bull. . . .Dmt. med. FVochenschr. .Engin. Mining J. . .Forlsehr, Landw. . .Bazzetta . . . .G'col. For. Forh. . . .Giurn. Chim. Ind. AppZ. .Hawaii Exp Sla. Bull. .I€&. Cham. Acta . .Ind. Eng. Ch?em. . . . T J . . . . .Jahrb. Min. Bed. - Bd.Jahrb. wiss. Bot. . .J. Agric. Rcs. . . .J. Agric. Sci. . . .J, Anwr. Cliem. Soc. . .J. Anter. Med. Assoc. , .J. Amer. P h r m Assoc. .J. Amer. Soc. Agron. , .J. Riot. Chem. . . .J. Chem. Met. SOC. X. AfricaJ. Chim.phys. . ..J. Exper. Med. . . . J. Franklin Inst. . .,T. @en. Physwl. . . .J. Indian Chem. Soc. . .FULL TITLE.Biologisches Zen tralblatt.Boletin de la Academia Nacional des Ciencias,C6rdoba.Botanical Gazette.Reports of the British Association for the Advance-Buletinul Societitei de Chimie din Romknia.Buletinul Sozietatii Romiina de Stiinte.Acadkmie royale de Belgique-Bulletin de la ClasseBulletin of the Chemical Society of Japan.Bulletin international de 1'Acadkmie Polonnise desBulletin de la Socikt6 chimiquo de France.Bulletin de la Sociktk ehimique de Helgique.Bulletin de la Socidt6 de Chimie biologique.Bulletin de la Socibt6 frangaise de MinBralogie.Centralblatt fur Mineralogie, Geologie und Palaonto-logie.Chemistry and Industry.Chemick6 Listy pro V6du a PrBmysl.Organ de la" CeskA ,phemickA Spole6nost pro Vedu aPrfiniysl.Chemical and Metallurgical Engineering.Chemical News.Chemische Umschau auf dem Gebiete der Fette, Oele,Chemisch Weekblad.Chemiker Zeitung.Le Ciment.Comptes rendus hebdomadaires des SBances deDepartment of Agriculture, Union of South Africa,Deutsche niedizinische Wochenschrift.Engineering and Mining Journal.Fortschritte der Landwirtschaft.Gazzetta chimica italiana.Geologisks Foreningens i Stockholm Fdrhandlingar.Giornale di Chiinica Industriale ed Applicata.Hawaii Experimental Station Bulletins.Helvetica Chimica Acta.Industrial and Engineering Chemistry.Journal of the Chemical Society.Nenes Jahrbuch fur 11 ineralogie, Geologie, undPalaeontolcgie, Reilage-Band.Jahrbuch fur wissenschattliche Botanik.Journal of Agricultural Research.Journal of Agricultural Science.Journal of the American Chemical Society.Journal of the American Medical Association.Journal of the American Pharmaceutical Association.Journal of the American Society of Agronomy.Journal of Biological Chemistry.Journal of the Chemical, Metallurgical, and MiningSociety of South Africa.Journal de Chimie physique.Journal of Experimental Medicine.Joilrnal of the Franklin Institute.Journal of General Physiology.Quarterly Journal of the Indian Cliemical Society.ment of Science.des Sciences.Sciences.Wachse, und Harze.l'Acad6mie des Sciences.Scientific Bulletinsviii TABLE OF ABBREVIA!FIONS EMPLOYED IN THE REFERENCES.Abbreviated Title.J.Indian Inst. Sci. .J. Ind. Hygiene . .J. Inst. Metah . .J. &finistry Agric. .J. Opt. SOC. Amer. .J. Pharm. Belg. . .J. Pharm , Exp. Ther.J. Pharm. SOC. Japan. .J. Physical Chent. . .J. Physio7. . . .J. Pomology . . .J. pr. Chem. . . .J. Roy. Micros. SOC. . .J. Xuss. Phys. Chem. SOC. .J . Soc. Chem. Ind. . ,J. SOC. Chem. Ind. Japan. ,J. Soc. Chem. Japan . .J . SOC. Dyem Col. . .Kgl. Danske Vidensknp.Selsk. math.-fys. Medd. .Kgl. Landtbruks Aknd.Handl. Tid. . . .Klin. Woch. . . .Maryland Agr. Exp. Stn.Bull. . . .Math. -Phys. kl. Sachs.dkad. . . . .Medd. K. Veten-skapsaX-ad.Nobel-Inst. . . .Mem, Manchester Phil. SOC.Hkm. Soc. Itzhsse Min. .Mikrochem. .. .Min. Mag. . . . .Mitt. deut. Landw.-Ges. ,Monatsh. . . . .Nach. Ges. Wiss. Gottingen.Naturwiss . . . .Natuwwetensch. Tijds. .Neuc Jahrb. Mi%Nwsk Beob. Tidsskrift .Notiz. chint. -id.O$. Gazette Brit. Guinm. .P . . . . . .Pharm. Weekblnd . ,Pharm. Zentr. . . .Pharm. Ztq. . . .Phil. Mag. . . .Phil. Tram. . . .FULL TITLE.Journal of the Indian Institute of Science.Journal of Industrial Hygiene.Journal of the Institute of Metals.Journal of the Ministry of Agriculture.Journal of the Optical Society of America.Journal de Pharrnacie de Belgique.Journal of Pharmacology and Experimental Thera-peutics.Journal of the Pharniaceutical Society of Japan.(Yakugakuzasshi. )Jonrnal of Physical Chemistry.Journal of Physiology.Journal of Polnology and Horticultural Science.Journal fur praktische Chemie.Journal of the Royal Microscopical Society.Journal of the Physical and Chemical Society ofJournal of the Society of Chemical Industry.Journal of the Society of Chemical Industry, Japan.Journal of the Chemical Society of J a p m (NipponJournal of the Society of Dyers and Colourists.Kongeljge Danske Videnskapernens Selskab, mathe-Kungliga Landtbruks Akademiens Handlingar ochKlinische Wochenschrift.Maryland Agricultural Experimental Station Bulle-Berichte uber die Verhandlungen der Koniglich.Sachsichen Gesellschaft der WissenschaftenMeddelanden fr&n Kunglig-VetenskapsakademiensMemnirs and Proceedings of the Manchester LiteraryMihoires de la Socidth Rnsse de Minkralogie (MoscowMikrochemie.Mineralogical Magazine and Journal of the Minera-hlitteilungen der deutschen Landwirtschaft-Gesell-Monatshefte fur Chemie nnd verwandte Theile andererNachrichten von der Gesellschaft der WissenschaftenDie Naturwissenschaften.Natuur~etenschappelijl\: Tijdschrift.Neue JahrbucE fur Minerdogie.Norsk Geolwisk Tidsskrift, Oslo.Notiziario c~~mico-indastriaIe.Oacial Gazette, British Guiana, Georgetown.Proceedings of the Chemical Society.Pharmaceutisch Weekblad.€'harmazentische Zentralhalle.Phnrmazeutische Zeitung.Philosophical Magazine (The London, Edinburgh andPhilosophical Trensactioas of the Royal Society ofRnssia.(K6gyB Kwagakii Zasshi.)Kwagaku Iiwai Shi.)matisk-fysiske Meddelelser.Tidskrift.tins.(math. -p4ys.Klase).No bel-Insti tut.and Philosophical Society.and Leningrad).logical Society.srhaft.Wissenschaften.zu Gottingen.Dublin).LondonTABLE OB ABBREVIATIONS EBWLOYED IN THE REFERENCES. ixAbbreviated Title.Philippine J. Sci. . .Physical Reo. . . .Proc. Amd. Eat. Sci.Philadelphia . . .Proc. Amer. Acad. Arts Sci.Physikal. 2. . .Proc. Amer. PhiE. SOC. .Proc. A m r . Soc. Hort. Sci.Proc. Camb. Phil. Soc. .Proc. Imp. Acad Tokyo .Proc. Indiana Acad. Sci. .Proc. R. Akad. Wetensch.Proc. Leeds Phil. Lit. SOC.AmsttrdaqnProc. Nut. Acad. Sci. , .Proc. Physical SOC. . .Proc. Roy. Soc. . . .Proc. Roy. SOC. New. SoulhWales . . . .Rec. trav. chim. . . .Rend. Accad. Sci. Jis. vialh.Napoli .. . .€lev. HJt. . . . .Sci. Papers Inst. Phys.Chem. RPS. Tokyo . .Sci. Proc. Roy. Dublin Soc.Sci. Rep. T6hoku Imp. Univ.Sitzungsber. Heide Zberg.Akad. Wiss. . . .Sitzungsber. Preuss. Akad.Wiss. Berlin . . .Skrifter Norske Vulenskaps-Akad, . . . .Soil Sci. . , . .Trans. Amer. Electrochem.SOC. . . . .Trans. Faraday SOC. . .Trans. oy. SOC. Canada .Ukruine Chem. J. . .Lrniv. Calif. Pub. Agr. Sci.Univ. Toronto Studies, CTeol.Ser. . . . . U. 8. Pub. E'ealth Rep. .Ver. Ges. deut. Naturforsch.Aertze . .Videmkapssl. Sk&ter:Kristiania. . . .Wisconsin Agr. Exp. Sta.a s . Bull. . . .Woch. Brau. . . .2. anal. Chem. . . ,2. angew. Chem.. . .2. anorg. Chem. . . .2. Elektrochem. . . .2. Krist. . . . .Z. Metallk.. . . .FULL TITLE.Philippine Journal of Science.Physical Review.Physikslischr Zeitschrift.Prbceedings of the Academy of Natural Sciences ofProceetliiigs of the American Academy of Arts andProceedings of the American Philosophical Society.Proceedings of the American Society of HorticulturalProceedings of the Cambridge Philosophical Society.Proceedings of the Imperial Acxdetiiy of Japati.Proceedings of the Indiana Academy of Scieuces.Koniuklijke Akadeniie van Wetenschappen te Amster-dam. Proceedings (English version).Procet-dings of the Laeds Philosophical and LiterarySociety.Procrudings of the National Academv of Sciences.Proceedings of the Physical Society of London.Proceediilga of the Royal Society.Proceedings of the Royal Society of New SouthRecueil des travaux cttimiques des Pays-Bas st de laRendiconto dell' Accademia delle Scienze Fisiche 6Revue de MBtallurgie.Scientific Papers of the Institute of Physical andScientihn Proceediitg~ of the Royal Dublin Society.Science Reports, T6hoku Imperial University.Sitzungsberichte der Heidelbeger A kademie derW issenschafteii.Sitzungsberichte der Preussischen Akademie derWissenschaften zu Berlin.Skrifter utgitt av det Norske Videnskaps-Akademi iOslo. I, Matem.-Naturvid.Klasse.Soil Science.Transartions of the American ElectrochemicalSociety.Transactions of the Faraday Society.Transactions of the Royal Society of Canada.Ukrctiniaii Chemical Joiirnal.University of California Publications in AgriculturalUniversity of Toronto Studies, Geological Series.United States Public Health Reports.Verhanillungen der Gesellschaft doutscher Natur-forscher utid Aertze.Videnskapsselskapts Skrifter. I. Mat. -naturv.Klasse, K r istiania.Wiscolr sin Agricultural Experimental Station Re-search Bulletins.Wochenschrift fur Brauerei.Zeitschrift fur analytische Chernie.Zeitschrift fiir angewandte Chemie.Zeitschrift fur anorganische und allgemeine Chemie.Zeitsc h rift fiir Elek trnch emie.Zeitschrift fur Krystdlogaphie.Zeitschrift fur Metallkunde.Phi ladrlpllia.Sciences.Science.\Vales.Helgiqne.Matematiclie, Nal'oli.Chemical Research, Tokyo.Sciences.AX TABLE OB ABBREVIATIONS EMPLOYED IN THE REFERENCES.Abbreviated Title. FULL TITLE.2. Pjeanz. Diing. . . Zeitschrift fur Pflanzenernahrung und Diingung.2. Physik . . . . Zeitschrift fur Physik.2. physikal. Chem. . . Zeitschrift fur physikalische Chemie, Stochiometrie2. phytwl. Chem. . . Hoppe-Seyler’s Zeitschrift fur physiologische Chemie.2. Verein. deuts. Zuckerind. Zeitschrift des Vereins der deutschen Zucker-und Verwandtschaftslehre.Industrie

ISSN:0365-6217    

DOI:10.1039/AR9272400001

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

ANNUAL REPORTSON TEEPROGRESS OF CHEMISTRY.GENERAL AND PHYSICAL CHEMISTRY.THE output of research in this branch of science continues toincrease, and this fact is marked this year by the inclusion of aspecial Report on Chemical Kinetics (p. 314), a subject whichincludes two Meldola Medallists (1923 and 1926) amongst its workersin this country. No attempt has been made to report on thewhole field of progress, and topics not recently dealt with haveas far as possible been chosen for discussion.The Atomic Nucleus.Two papers of outstanding interest have been published thisyear, and it is considered that their importance justifies theirinclusion here in anticipation of next year’s Report on Radio-activity and Sub-atomic Phenomena.The construction of an improved form of mass spectrographhas been described by F.W. Aston in the Bakerian Lecture tothe Royal Society, The new instrument has a resolving powerfive times, and an accuracy ten times, as great as the original0118.2 These improvements have been effected, not by a change ofprinciple, but by doubling the angles of magnetic deflexion, andsharpening the lines by the use of finer slits placed farther apart.The dispersion varies from 1.5 mm. to 3 mm. for a change of massof 1%, but owing to the fact that the lines on the plate areirregulrtrly curved and change gradually in shape throughout thespectrum, it is necessary to compare masses, which must not differby more than 1%, by the accurate measurement of (a) the distancebetween the lines, and ( b ) the dispersion constant a t the mid-pointbetween them.These measurements are applied in different waysto suit different cases, the most generally applicable one beinga modification of the original bracketing method.1 PTOC. Roy. SOC., 1927, [ A ] , 115, 487; A,, 914.Ann. Reports, 1920, 17, 22112 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.The results are now so accurate that the loss of an electron(mass = 0.00054; H = 1) in the formation of a positive particle isgenerally significant and must be allowed for. Determinations ofmass are now made to within 1-2 parts in 10,000 parts, and, as aresult, it is found that most of the elements have atoms whosemasses deviate from the whole-number rule, although not, ofcourse, to the same extent as does hydrogen.I n fact, there arenow three fundamental numbers characteristic of every atom :(i) the mass number, giving the number of protons in theatom,(ii) the atomic number, giving the number of extranuclearelectrons,(iii) the packing fraction, which is an indication of the forcesbinding the nuclear protons and electrons, and is thusa measure of the instability of the nucleus.The packing fraction is 10,000 times the departure from thewhole-number rule (when 0 = 16-000) divided by the mass number,and has a value 77.8 for hydrogen. Since loss of mass may be takenas equivalent to release of energy due to close approach of protonsand electrons in the nucleus and consequent partial annihilation oftheir electromagnetic fields, it follows that high packing fractionsindicate looseness of packing and therefore low stability, and lowpacking fractions the reverse.When the packing fractions of the atoms are plotted against theirmass numbers, it is found that all but light atoms of even atomicnumber (helium, carbon, and oxygen) lie on a smooth, non-periodiccurve which descends steeply from hydrogen (+ 77.8) throughfluorine (& 0) to a minimum a t bromine (- 9), thereafter risingmuch more gently to cross the axis again at about mercury.Thelight atoms of even atomic number have packing fractions wellbelow this curve, and approximate to a branch rising much lesssteeply to helium (+ 5.4). The observed stability of the nuclei ofhelium, carbon, and oxygen (beryllium has unfortunately not yetbeen measured) is in accord with their position on the lower curve.Incidentally, the research has settled the isotopic constitutionsof mercury and xenon, and has recorded new isotopes of sulphur andtin, bringing the number of isotopes of the last-named element upto eleven.Sir E.Rutherford has put forward a theory of the structure ofthe nucleus of a radioactive atom. The nucleus is imagined toconsist of a central part around which revolve " neutrons "-a-particles plus two electrons (potential helium atoms)-in quant-Phil, Mag., 1927, [vii], 4, 680; A,, 1002GENERAL AND PHYSICAL CHEMISTRY. 13ised orbits. If the system should for some reason become unstable,the “ neutron ” is ejected as an a-particle, and its two electronscirculate close to the central nucleus with a velocity approachingthat of light.One of these may later be hurled from the atom asa @-ray. Either of these changes may be accompanied by arearrangement of the “ neutron ” orbits involving the emission ofy-rays. In all cases the changes are governed by quantumrelations.Refractivity and Refractive Dispersion.The departure from additivity of molecular refractivity has beencalculated on the hypothesis that the electron shells of the atomsin the molecule are displaced (polarised) by the proximity of otheratoms. The case for organic molecules is dealt with by K. Fajansand C. A. K n ~ r r . ~ E’or saturated hydrocarbons the problem issimple. According to the Lewis-Langmuir electronic theory ofvalency, the 8 valency electrons of the carbon shell in methane areregarded as equally distributed amongst four carbon-hydrogenbonds, so that one-fourth of the molecular refraction of methanerepresents the value for one such bond.The refractive equivalentof a carbon-carbon linking may be obtained by subtracting sixtimes the value of a carbon-hydrogen bond from the molecularrefractivity of ethane. With substituted hydrocarbons, however,the problem is not so simple. Methyl chloride, for example, con-tains three carbon-hydrogen bonds and one carbon-chlorine linking,and the refractivity for the chlorine atom in these circumstances isconsidered to be due to the combined influence of the bonding pairof electrons and the three lone pairs. It is thus nearly the sameas the refractivity of the chlorine atom in hydrogen chloride andis lower than the refractivity for the free chlorine ion.The refrac-tivities for a large number of groupings are worked out in this way.Somewhat similar considerations are applied by T. H. HavelockY5who treats atoms as isotropic resonators in fixed relative positionsin the molecule.The case for ions in solution has been worked out by K. Fajans,6who points out that the refractivity of an ion is a measure of theease of displacement of its electron shells with respect to thenucleus. An anion is rendered more rigid by the proximity ofpositively charged kations, since the positive charges tend tobalance the inward attraction of the positively charged nucleus.Its refractivity thus tends to fall.Conversely, the proximity ofnegatively charged anions tends to displace the electron shells of aBer., 1926, 59, [B7, 249; A., 1926, 336.Phil. Bag., 1927, [vii], 3, 158, 433; A., 189, 294.ti Trans. Paraday SOC., 1927, 23, 357; A., 102314 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.kation, since now the attractive force of the nucleus is reinforced bythe repulsive effect of the neighbouring anions. Its refractivitytherefore tends to rise. “The union of ions into molecules orcrystals will thus be accompanied by a net diminution of therefractivity whenever the consolidating effect of the kation uponthe anion outweighs the loosening effect of the anion on the kation,and vice versa.”K. I?. Herzfeld and K.L. Wolf and B. Davis 8 have attemptedto fit dispersion equations involving one or more frequency termsto the observed data for elements and compounds, but R. A. Mortonand R. W. Riding consider that no satisfactory two-term equationfor the variation of refractive index with wave-length can beobtained until further absorption data are secured in the short-wave ultra-violet region of the spectrum. They are of the opinionthat existing data are best fitted by equations of the type : lo(n - WV1 + v, + v3 + . .) = V1N1/(V,2 - v2) +72N,/(v22 - v2) + V3N3/(v,2 - v2) + . . .where n representa the refractive index; V,, V2, etc., the volumesof the respective molecular phases; l1 N l , N,, etc., constantsassociated with the respective molecular phases ; v the frequencya t which the refractive index is observed; and vl, v2, etc., the oscill-ation frequencies associated with the respective molecular phasesand are all integral multiples of a fundamental frequency in theinfra-red.The conclusions of H.Hunter l2 and others13 that the neglectof the dispersion factor is possibly responsible for the failure ofthe generally accepted methods of applying refractometric data t oproblems of chemical constitution receive experimental supportfrom the work of H. Voellmy.14 This author has examined themolecular refractivities of more than 30 organic liquids a t wave-lengths between 6560 and 2100 8., and has shown that the refract-ivity does, in fact, increase on the long wave-length side of anabsorption band and decrease on the other side in accordancewith theory.Workers on refractivity in the infra-red will do well to note thewarning of Sir R. Robertson and J.J. I ? o x , ~ ~ that the temperatureAnn. Physik, 1925, [iv], 76, 71; A., 1925, ii, 182.Physical Rev., 1925, [ii], 26, 232; A., 1925, ii, 933.Phil. Mag., 1926, [vii], 1, 726; A., 1926, 658.lo E. C. C. Baly and R. A. Morton, J . Physical Chem., 1924, 28, 659; A.,l1 Ann. Repom, 1915, 12, 6.l4 Z. physikal. Chem., 1927, 127, 305; A., 812.l6 Nature, 1927, 119, 818; A., 607.1924, ii, 714.l2 Ibid., 1923, 20, 15.F. R. Goss, C. K. Ingold, and J. F. Thorpe, J., 1924,125, 1927GENERaL AND PHYSICAL CHEMISTRY. 15coefficients of refractive index for rock salt and fluorite are importantand cannot be neglected.Molecular Volume.One of the outstanding achievements of the electronic theory ofvalency is the prediction of two kinds of double bond-the semi-polar double bond, occurring mainly but not exclusively in inorganiccompounds, and the non-polar double bond which is chiefly, butagain not entirely, to be found in carbon compounds.For sometime after the theoretical prediction of the existence of the semi-polar double bond there was no experimental method of detectingits presence ; now, however, there are three methods available.In order of priority we have : (a) the parachor,16 (b) resolution intooptical enantiomorphs, l7 ( c ) zero volume.18Of these, (b) is an absolute method, but is obviously limited inapplication to a very few compounds, although it can be appliedto solids as well as to liquids, (a) is of more extended applicability,but is limited to non-associated liquids, whilst (c) can be appliedto all liquids.Method (b) is outside the scope of this Report.The principleunderlying method (a) has already been described,l9 but hasrecently been greatly extended in application. The examination 20of a large number of double-bonded compounds by the method ofthe parachor has shown that such substances fall into two sharplydefined classes, one showing an increase in the parachor of 23.2units due to the presence of the double bond, and the other adecrease of 1.6 units. The evidence is clear that the first classrepresents the non-polar linking and the second the semipolar.Itis found that in every case where a carbon atom is concerned inthe double bond the linking is non-polar. T. M. Lowry’s suggestionto tthe contrary,21 improbable enough on other grounds, is thusruled out of court, a t all events as far as molecules not in a reactingstate are concerned.A later paper 22 lends support to the view that the double bondsin maleic-fumaroid geometrical isomerides are non-polar, andindicates that isomerism of this type has little or no effect on the16 S. Sugden, J., 1924, 125, 1185.1 7 H. Phillips, J., 1925, 127, 2552; P. W. B. Harrison, J. Kenyon, andH. Phillips, J., 1926, 2079; S. G. Clarke, J. Kenyon, and H. Phillips, J.,1927, 188.1* S. Sugden, J., 1927, 131.19 Ann. Reports, 1924, 21, 8.20 S.Sugden, J. B. Reed, and H. Wilkins, J., 1925, 127, 1625.21 J., 1923, 123, 822.23 S. Sugden and H. Whittaker, J., 1925, 127, 152516 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.parachor. A similar conclusion,% that 0-, m-, and p-isomerideshave identical values for the parachor, has also been reached. Theevidence of the parachor in every case supports the maintenanceof the octet as against shells of 6, 10, or 12 electrons. S. Sugdenand H. Wilkins have determined the effect of ring structure on thep a r a ~ h o r , ~ ~ and have correlated the values so found with the degreeof unsaturation measured as the quotient of the number of latentvalencies by the number of octets involved. The figures, givenbelow, are striking.LatentvalenciesStructure.(x).Triple bond .................. 4Double bond .................. 2Three-membered ring ...... 2Four-membered ring ...... 2Five-membered ring ...... 2Six-membered ring ......... 2Degree ofunsatur-Octets ation2 2.0002 1.0003 0.6674 0.5005 0.4006 0.333(n). (xln).Parachor,obs. calc.46.6 46.4(23.2) (23.2)17 15-511.6 11-68.5 9.36.1 7.7The view that structural constants affecting the parachor havevalues proportional (to a first approximation) to the degree ofunsaturation involved receives additional support from the valuefound for the semipolar double bond (- 1.6); this bond is notunsaturated and therefore we should expect it to have no influenceon the parachor. The slight negative value actually observed isprobably due to a small contraction in volume caused by electro-static attraction (rendered obvious when the semipolar double bondis written thus : S-0).Compounds of phosphorus and arsenic have been examined,25and Sugden considers that the formula suggested by E.B. R.Prideaux 26 for phosphorus pentachloride, which involves a single-electron bond (" singlet ") between the phosphorus atom and eachof two of the chlorine atoms linked to it, the other three beingheld in the normal manner by duplets, best represents the facts.This has the advantage that it preserves the rule of eight inviolate,but N. V. Sidgwick 27 considers another explanation preferable.Finally, F. B. Garner and S. Sugden have applied the method todecide between tautomeric ring and chain formulae for quinones,benzils, and succinyl and phthalyl chlorides, and find that allexcept the last-named have the normal structure and cannot inthe liquid form contain more than traces of the ring isomeride.In+ -23 S. Sugden and H. Wilkins, J . , 1927, p. 2517.Z4 Idem, ibid., 1927, 139.z5 Ibid., p . 1174.26 Chem. and Ind., 1923, 42, 672.2' " The Electronic Theory of Valency," Oxford Univ. Press, 1927, p. 130.a* F. B. Garner and S. Sugden, J., 1927, 2877GENERAL AND PHYSICAL CHEMISTRY. 17the case of phthalyl chloride, the high-melting form was shown tohave the unsymmetrical, and the low-melting form the symmetrical,structure.Sugden has also shown29 that the variation of density withtemperature from the freezing point to the critical point is repre-sented accurately for normal liquids by the equation :where D and d are the densities of the liquid and vapour a t To K.,T, is the critical temperature on the same scale, and Do is a con-stant representing the liquid density a t absolute zero. This equa-tion also holds for associated liquids at lower temperatures. Thezero volume,” Vo, obtained by dividing the molecular weight byDo, is found to be nearly proportional to the critical volume, thefactor of proportionality being about 0.27.The zero volume thus obtained is an additive function of thefollowing constants?O the observed values lying within 2% ofthose calculated for 236 out of 284 compounds considered.D - d = Do(1 - T/Tc)0’3,66Atomic constants.Structural constants./--p/L H = 6.7 I = 28.3 Triple bond = 15.5 c = 1.1 P = 12.7 Double bond = 8.0N = 3.6 S = 14.3 Three-membered ring = 4.80 = 5.0 0 (inalcohols) = 3.0 Four-membered ring = 3.2F = 10.3 N (insmines) = 0.0 Five-membered ring = 1.8C1 = 19.3 Six-membered ring = 0.6Br = 22.1 Semipolar double bond = 0.0The difference between the values for non-polar and semipolardouble bonds is noteworthy, and it will be observed that there isthe same connexion between the values for the structural constantsand their degree of unsaturation as in the case of the parackor,although the quantitative agreement is not so good.Other, less successful, relationships 31 have been put forwardrecently, notably Vopc/Tc = const.and modifications of this (pchere represents the critical pressure, the other symbols have theirprevious significance).W. Herz 32 has also correlated Vo with latentheat of vaporisation, the Poisson capillarity constant, molecularelevation of the boiling point, and the difference between thespecific heats at constant pressure and constant volume. A closeconnexion between molecular volume and molecular refra~tivity,~~29 F. B. Garner and S. Sugden, J., 1927, 1780.30 Ibid., p. 1786.31 R. Lorentz and W. Herz, 2. anorg. Chew., 1924,375; A,, 1925, ii, 25, 183; W. Hem, ibid., 1925, 149,A., 1926, 110, 778.32 Ibid., 1926, 153, 269; A., 1926, 786.33 €4. Lorentz and W. Herz, &id., 1925, 1142, 80; A.,140, 379; 1925, 141,270; 1926, 153, 339;1926, ii, 36618 ANNUAL REPORTS ON THE PROGRESS OP CHEMISTRY.and between molecular refractivity and the parachor 34 have alsobeen indicated.The Metastability of Matter.The view that elements and compounds, even when chemicallypure, may not be physically homogeneous, is gradually gainingground and seems destined to prove of great importance.Only afew years ago, the phenomena of allotropy and polymorphism wereregarded as the exception rather than the rule, yet to-day E.Cohen 35 is able to state his belief that “ every solid substance mayexist in two or more modifications ” and that “ many of the hithertorecognised physical or physicochemical constants of solid substancesare values which refer very often, if not always, to metastablemixtures which contain two or more modifications of that substancein unknown proportions ” so that “ no definite importance can beassigned to such constants.” This behaviour of solids-their dis-inclination to change a t once into stable modifications a t theappropriate transition point-is, of course, not an unmixed evil.Many of the special steels, to take a familiar example, depend fortheir properties on constituents deliberately added to prevent suchchange.Nevertheless, such wholesale doubt cast upon the accuracyof physical properties, determined without special precautions toensure physical as well as chemical purity, is disturbing. Nor isthe doubt confined to solids. Liquids and gases-as shown byexperiments on intensive drying-must also be considered, evenwhen chemically pure, as more or less complex mixtures.In the case of some substances, of course, it has long been knownthat metastability over a long period of time occurs. E.Cohen36has recently directed attention to the fact that as long ago as 1847,St. Claire Deville pointed out that the stabilisation of solid sulphurat the ordinary temperature was not complete even after 8 years,as indicated by a progressive change in density. In the classicalcase of tin, too, it has been shown that the physical properties aredependent on the previous thermal history of the sample,37 and itis only recently38 that the true densities and specific heats of thewhite and grey varieties have been determined. A similar uncer-tainty exists in the case of84 W. Herz, 2.anorg. Chem., 1937,159, 316; A., 189.35 “ Physico-chemical Metamorpbosis and Problems in Piezo-chemistry,”McGraw-Hill, 1926, p. 50.8 6 2. physikal. Chem., 1924, 109, 109; A., 1924, ii, 450. See also “ ThePhase Rule,” A. Findlay, Longmans, 1923.3 7 A. Travers and Huot, Compt. rend., 1927, 184, 162; A,, 194.38 E. Cohen and K. D. Dekker, 2. physikal. Chem., 1927, 12’7, 183; A.,39 D. Cannegieter, Chem. Weekblad, 1927, 24, 350; A., 818.818GENERAL AND PHYSICAL CHEMIS!FRY'. 19Compounds axe equally difiicult to deal with. The differentcrystal structures-cubic and hexagonal-assigned to silver iodideby different workers are considered40 to be due to the metastableexistence of one form in the stable region of the other. The heatsof solution of two forms of cadmium iodide have been measured41and earlier discrepant results shown to be due to physical hetero-geneity.Ammonium nitrate is a particularly glaring case in-vestigated by R. G . Early and T. M. Low~Y.*~ It can exist in nofewer than six solid modifications, and recent determinations ofthe transition temperature of, and the volume change accompany-ing, the I11 * IV transformation have been made,43 confirming thetemperature found by Lowry and Early, but differing by 8% fromthe volume change determined by Bridgman.44The question of the preparation of physically pure modificationsof a substance is a difficult one. Since, in any change of state,metastable modifications may be produced in preference to stableones (Ostwald's rule of the succession of phases) it is obvious thatcrystallisation, freezing, sublimation, distillation, etc.-the verymethods employed for chemical purification-will almost inevitablylead to the formation of metastable modifications.The question ofphysical purification therefore resolves itself into one of acceleratingthe stabilising change after the metastable modification has beenproduced, and it has been shown that repetition of the transitionprocess a number of times is one method of effecting this45-thepresence of a solvent for one form,46 or even of water 47 or electro-lytes, is another. The presence of adsorbed impurities48 is alsoeffective in many cases. The only evidence of physical purity isthe constancy of physical properties of different specimens-anegative test, but the only one available.The effect of intensive drying on the properties of liquids andsolids has been studied-particularly by H.B. Baker,49 A. Smits,60and S. B. MalL51 The results obtained by Smits on the self-40 E. Cohen and A. L. T. Moesveld, 2. physikal. Chem., 1924, 109, 97; A . ,1924, ii, 450.I1 E. Cohen, W. D. Helderman, and A. L. T. Moesveld, ibid., p. 100; A . ,1924, ii, 450.43 J., 1919, 115, 1387.43 E. Cohen and J. Kooy, 2. physikal. Chem., 1924, 109, 81; A., 1924, ii,44 Proc. Amer. Acad. Arts Sci., 1916, 51, 581.4 5 '' Physico-chemical Metamorphosis, etc.," p. 87.46 E. Cohen and A. L. T. Moesveld, 8. physikal. Chem., 1920, 94, 450;46 Amer. J . Xci., 1916, [iv], 16, 504.4n Inter alia, J ., 1922, 121, 668.6o Inter alia, J . , 1924, 125, 2573.61 2. anorg. Chem., 1925,149, 150; A., 1926, 117.449.A., 1920, ii, 611. 4 7 Vide inEra, Ref. 6820 ANNUAL REPORTS ON THE PROGRESS OF CHIEMISTRY.intensive drying of sulphur trioxide and phosphorus pentoxide havealready been described.52 The general effect of intensive drying onliquids has been to lower the vapour pressure, but that of nitrogentetroxide 53 was raised. H. B. Baker has now shown that changesin vapour pressure and molecular complexity in liquids can beproduced by means of catalysts (the author's term) such as char-coal, platinum-black, or th0ria.~4 His view is that " all liquidsmay be regarded as analogous to a dissociable gas such as nitrogentetroxide. . . . Liquids differ, however, in this respect, that dis-sociation and association are much slower in liquids than in gases.Equilibrium in liquids may be profoundly disturbed by even a com-paratively slight change of temperature, and complete recovery ofthe normal condition may be a question of weeks or even months.''These observations are confirmed by J.B. Peel, P. L. Robinson,and H. C. Smith,55 who report changes in density under similarconditions. The following figures for water with thoria as catalystgive an idea of the magnitudes of the observed changes :Molecular complexity. Density.After3 weeks ......... 3.125 x 18 After 1 day ............ - 0.000179 weeks ......... 3.866 x 18 4 days ......... + 0-000019 days ......... + 0.000155 weeks .........3-612 x 18 2 days ......... - 0.000028 days ......... + 0.00011Vapour pressure : + 2-4 111~. before heating; + 4.0 mm. after heating at80" for 48 hrs., then cooling to 20"; + 1.2 mm. 1 day later; + 0.9 mm.2 weeks later.In this connesion, the observations of G. Tammann 56 are ofinterest. This author, from an examination of specific volume andcompressibility data, deduces the presence of large molecules of" water-I," (H,O),, with the space lattice of ice-I. The concen-tration of these molecules falls with rise of temperature or pressure,and disappears a t 50" or 2500 kg./cm.2. With regard to the effectof intensive drying on the properties of liquids, D. Balarev 5' statesthat repetition of Baker's experiments gave liquids which invariablycontained phosphorus, and he suggests that the formation of volatilecompounds of phosphorus is the cause of the observed phenomena.Baker, however, has pointed out 57a that, apart from the factthat the large elevations of boiling point observed could not be dueto this cause, his published paper definitely states that all the52 Ann.Reports, 1924, 21, 30.68 A. Smits, W. de Liefde, E. Swart, and A. Claassen, J., 1926, 2657;64 J . , 1927, 949.5 6 Nature, 1927, 120, 814; A., 1019.5 6 2. anorg. Chem., 1926, 158, 1; A., 1927, 93.67 J . pr. Chem., 1927, [ii], ll$, 5 7 ; A., 613.57a J., 1927, 2902.J. W. Smith, J., 1927, 867GENERAL AND PHYSICAL CHEMISTBY. 21liquids were examined for phosphorus, with negative results. Hesuggests that Balarev’s results are possibly due to the presence ofvolatile phosphorus trioxide in the pentoxide used.A.Smits 58 considers that every phase of an allotropic substancecontains different molecular species which may be isomerides,polymerides, or dissociation products of the simple molecule.Normally, inner equilibrium between these forms is rapidly estab-lished, and the system behaves as a unary one, but in certain cir-cumstances (intensive drying) the establishment of this innerequilibrium may be rendered very slow, or even stopped altogether.Alternatively, the inner equilibrium may be fkst displaced and thenfixed in its new position. In the simple case where two componentsonly are concerned, three cases may arise :FIG. 1.dmJmoistA X . iComposition.FIG. 2.moistdryA X.Composition.(i) Both forms are more stable in the moist than in the dry state.Then two curves for the chemical potential (C) as a function of thecomposition (x) are obtained (Fig.l), and it will be a coincidence ifboth curves have minima (equilibrium points) a t identical valuesof x. The equilibrium position will therefore be shifted by intensivedrying, but the direction of the change cannot be predicted.(ii) A may be more stable in the moist, and B in the dry, state.We then get the condition of affairs represented in Fig. 2 and theconclusions are as before.(iii) Intensive drying may have no effect on the stability ofeither form-the <--x curves for moist and dry conditions are thenidentical, and no effect will be produced by intensive drying.It is obvious that these views can be applied to the action ofcatalysts other than water.68 J., 1926, 2655.Compare A. Smits, “ The Theory of Allotropy,” Long-mans, 192222 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Strong Electrolytes.The Debye-Huckel theory still continues to attract considerableattention and much work has appeared on this subject during theyear. Hence, although this section was included in the Reportsfor the last two years, which stressed mainly the agreement of thetheory with observation, the opportunity is taken this year ofrecording some of the work which has gone to make up the otherside of the picture.W. D. Bancroft 59 has revived H. E. Armstrong’s conception ofthe complexity of water, although in a more comprehensible form.He suggests that many of the anomalies of strong electrolytes, inparticular the neutral-salt effect and the failure of the Ostwalddilution law, may be due to a disturbance of the equilibria betweenthe various polymerised or associated molecules of which liquidwater is generally considered to consist.He is of the opinion that“ there is very little to be gained by devising empirical formulaswhich ignore this factor.” His pronouncement,60 that physicalchemists in this field are ignoring reality and working with “ slightlypolluted water,” since their formula break down at concentrationsgreater than about O-OlM, will possibly pass into history.The bulk of the work recorded goes to demonstrate the essentialcorrectness of the theory and, where disagreement is expressed, itis generally on matters of detail.On the question of completeionisation, for instance, the Arrhenius theory leads to figures foruni-univalent strong electrolytes from conductivity measurementsof about 90-95% ionisation at about 0~01--0~001M, whereas thenew theory demands 100~o. The tendency now seems to be toadmit a compromise, in some cases up to a figure of 3% (or there-abouts) of ionic association. For instance, K. Fajans 61 has em-ployed refractometric means to test the theory and finds that hismeasurements indicate, in general, incomplete ionisation and, inparticular, that in solution a chlorine ion can approach more closelyto a lithium ion than to a sodium ion, a conclusion in direct conflictwith the theory.It is urged, therefore, that the parameter whichDebye calls the radius of the ionic atmosphere has not really thatphysical significance. D. A. MacInnes and I. A. Cowperthwaite,62from measurements of transport numbers, draw similar conclusions.L. 0nsagerG3 has modified the Debye-Hiickel equation for con-ductivity g4A, - A, = Ao(Klwl + K2b)d.%59 J . Physical Chenz., 1926, 30, 1194.6o J . Amer. Chem. SOC., 1926, 48, 94 (Jubilee No.).G3 Ibid., p. 341; A., 1031.This Report, p. 13. 62 Trans. Par&qSoc., 1927,23,400; A,, 1031.fie Ann. Reportp, 1925, 22, 36GENERAL AND PHYSICAL CHEMISTRY. 23by introducing a correction for the Brownian movement of theions. In the case where the mobilities of the ions of a uni-univalentelectrolyte are equal, the correction term becomes 2 - 4 3 , so thatthe equation becomesA, - A, = A,[K1(2 - 4 2 ) + K2b]d%since wl = &(l& + &/la), where la and I, are the mobilities andare equal in this case. For potassium chloride, with A, = 129.9,the original expression leads toA, - A, = 0*5471/%,whereas Onsager's givesA, - A, = 0*4332/2C,as against the experimentally observed value 0.4612/%.Eventhen, however, the results indicate association of the ions intomolecules a t quite low concentrations. H. B. Hartley and R. P.Bell,65 from conductivity data, and C. A. Kraus and R. P. Seward,60from solubility data, consider that incomplete ionisation must berecognised in solvents other than water and possibly methyl alcohol.Both G.Nonhebe1,G' from E.M.F. measurements, and C. W.Davies,68 from conductivity measurements, prefer the Milnercoefficient in the activity equationto express their results. (For uni-univalent electrolytes, the Debye-Huckel theory requires A = 0.5, and the MiJner theory at a i d c a n tconcentrations requires A = about 0.39.)The failure of the DebyeHuckel theory to deal with the case ofsmall ions of high valency has been shown by N. Bjerrum 69 andD. L. Chapman 70 to be due to the inapplicability of the approxim-ation sinh + / E t = +/kt under these conditions. W. Nernst andW. Orthmann 71 state that the heats of dilution of salts of thesame valency type a t low and very low concentrations are not thesame, and are in some cases even negative, and hence do not agreewith the theory, and their view receives partial support from thework of P.G r ~ s z . ' ~ N. B j e r r ~ m , ~ ~ however, asserts that these andlogf= - Ad;6 5 Trans. Paraday SOC., 1927, 23, 396; A,, 1032.O6 Ibid., p. 488; A., 1021.67 Phil. Mag., 1926, [vii], 2, 1086; A,, 1927, 21.O 8 Ibid., 1927, [vii], 4, 244; A,, 936.KgE. Damke VVidenskab. Selsk. math.-fys. Medd., 1926, 7, [9], 1; A,,1927, 314. '' TTan8. ParaChy SOC., 1927, 23, 443.71 Sitzungsber. Preuss. Akad. Wiss. Berlin, 1926, 51; 1927, 136; A., 1926,73 Trans. Faraday SOC., 1927, 23, 445; A., 1028.579; 1927, 733. 73 Monatsh., 1927, 48, 243; A,, 94024 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.other small discrepancies may be quantitatively explained byassuming a decrease of the effective dielectric constant of thesolution in the immediate neighbourhood of the ions.One clear-cut issue is the formulation of an equation to representthe conductivity of a strong electrolyte as a function of the con-centration.Four such equations have recently been proposed :(1) 74 1 - ~ , p , = o q V - i)[pco'5 - 2yc + 3 w 5 . . .I(2) 75 A, - A, = Bc"(3) 76 A, - A, = Aco5 - ABc( 4 ) 77 A, - A, = A / ( B + c-"')where A, and A, are the equivalent conductivities a t infinitedilution and concentration c, respectively, v is the number of ionsinto which the electrolyte dissociates, and p, y, 6, A , B, and n areconstants typical of the electrolyte. Of these, all except (2) aredevised to reduce to the formwhen c is small, in order to be so far in accord with the Debye-Huckel theory.Equation (2) has the advantage that it does notprejudge the issue as to the value for the index for c. By suitablechoice of variables, Ferguson and Vogel have established the facts,not only that equation (2) will represent the experimental figures,but also that n, when determined without any preconceived ideas asto its value, never has the value 0.5, and varies from electrolyteto electrolyte. Their view is that n and B are functions of theionic masses and that conductivity measurements do not supportthe DebyeHuckel theory, a t least in its present form. Theirconclusions are thatA, - A, = XCO'~(a) the constants B and n vary from electrolyte to electrolyte ina regular manner for related electrolytes ;(b) the extreme variations of n are from 0-3742 for potassiumchloride at 25" to 0.9687 for iodic acid at the same temperature,although most of the values lie within 20% of 0.5;(c) both B and n vary with temperature, although there are notsufficient data available to determine the precise mode of thisvariation ;( d ) the formula is applicable to uni-uni-, uni-bi-, and bi-bi-valentelectrolytes, and to water and (as far as data are available) methyl74 B.Szyszkowski, Bull. Acad. Polonaise, 1926, [A], 325; A., 1927, 415.75 A. Ferguson and I. Vogel, Phil. Mag., 1925, [vi], 50, 971; 1927, [vii],4, 1, 233, 300; Trans. Faraday SOC., 1927, 23, 404; A., 1925, ii, 1163; A,,936, 941; I.Vogel, Phil. Mag., 1928, [vii], 5, 199.7 g Inter alios, L. Onsager, Trans. Paraday SOC., 1927, 23, 341.7 7 R. T. Lattey, Phil. Mag., 1927, [vii], 4, 831GENERAL AND PHYSICAL CHERIISTRY. 25alcohol and nitromethane as solvents. It is also applicable tostrong acids such as hydrochloric and iodic.It is of course possible that their results are capable of other inter-pretations. The fact that an empirical equation will fit given setsof figures is no guarantee a t all that it is the correct equation toapply, and it is obvious that the good agreement obtained byFerguson and Vogel by variation of the coefficient and the exponentof c can equally well be obtained by varying A and B in equations(3) and (4). Indeed, equation (4) represents the facts for potassiumchloride in aqueous solution a t much higher concentrations thanany of the others, except equation (1) with its unlimited supply ofarbitrary constants, but in doing so it would seem to prove toomuch, since it applies in regions of concentration for which theDebye-Huckel theory itself is not valid.Nevertheless, Fergusonand Vogel have effectively refuted the claim that the simple square-root formula of Kohlrausch best represents the dependence of theconductivity of strong electrolytes on concentration, and they havedone yeoman service by their resolute appeal to the test of experi-ment at a time when theoretical formulae are being applied some-times with more enthusiasm than discretion.Equilibria between Gases.S. W. Saunders 78 has collected and analysed the available dataon the molecular heats of gases, heats of reaction, and chemical andequilibrium constants for ten well-known reactions involving carbon,hydrogen, oxygen, and nitrogen.The results obtained should be ofvalue in the study of fuel-gas production, reactions in the cylindersof internal-combustion engines, detonation of high explosives, etc.The method employed was to fit equations empirically to the mole-cular heat-temperature curves in each case, and then, by integratingthe van ’t Hoff isochore and applying the Nernst heat theorem, tocalculate the best values for the equilibrium constants. Since theavailable data are not critically accurate, the Nernst conventionalchemical constants were used for the calculation. Where chemicalconstants were not available, they were calculated either by thevan der Waals-Nernst equation or by the Trouton-Nernst rule.In general, the equations obtained for the equilibrium constantsagree well with the experimental figures when these are available,and the results agree on the whole with those published by G .N.Lewis and M. Randall.79 J. R. Partington and W. G. Shillings0have critically surveyed the figures for the water-gas equilibrium’* S. W. Saunders, J. Physical Chem., 1924, 28, 1151; A., 1924, ii, 836.7D “ Thermodynamics,’’ McGraw-Hill, 1923.80 J . SOC. Chem. Id., 1926, 44, 1 4 9 ~ , 242r26 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.and, by following substantially the same procedure except thatthey used experimental values and did not apply the Nemttheorem, obtained the following equation :log,, K =z - 2125/T + 1.077 loglo T - 0.000898T +0~000000133T2 - 0.5425where K = pco, .p ~ , / p c o ~ .p~,,. The agreement of Saunders'sfigures with those of Partington and Shilling is illustrated below :T" K. .................. 1000 1200 1400 1600 1800K (Saunders) ......... 0.71 1.29 2-04 2.95 3.72K (P. and S.) ...... 0.63 1-31 2-15 3-05 3-91K (exptl.) ............ 0.65 1.32 2-08 2.95 3.80All the above values refer, of course, to true equilibrium whichtakes some time to obtain. In actual combustion practice, thegases are rarely in contact for a sufficiently long period of time forthe attainment of true equilibrium. It has been found, however,by R.T. Haslam 81 from his own results and those of other workers,that in actual water-gas producers, a false equilibrium correspondingfairly well to K' = O.O96L, where L is the depth of the fuel bed infeet, is attained.R. C. Cantelo 82 has investigated the equilibriumC(amorph.) + 2H2 CH, + 21,730 cal.both theoretically and experimentally. In the theoretical in-vestigation he takes account of ten possible reactions involvingmethane, ethane, ethylene, acetylene, benzene, carbon, and hydro-gen, and, by an application of the Nernst approximation formula,shows that in all cases the final equilibrium system consists ofmethane, carbon, and hydrogen, with less of the first as the tem-perature rises. He confirms the equation deduced by Saunders(Zoc.cit.) and shows that the apparent disagreement between theearlier results of Mayer and A l t m a ~ e r , ~ ~ Bone and Coward,*4and Coward and Wilson85 may be reconciled by the use of theabove value for the heat of reaction with amorphous carbon, inplace of the value 18,500 cal./g.-atom for graphite. In order toattain equilibrium in a reasonable time, it is necessary to use anactive catalyst (nickel in this instance) and to pass the gaseousmixture repeatedly over it. From the results obtained, the free-energy decrease for the above reaction is calculated to be - AFZQ8 =14,500 cal., which, combined with the value - AFgg8 = 12,800 cal.I n d . Eng. Chem., 1924, 16, 782.82 J . Phyaical Chem., 1926, 30, 1641; 1927, 31, 124, 246, 417; A., 20, 204,321, 322.Ber., 1907, 40, 2134; A ., 1907, i, 457.*4 J., 1908, 93, 1197.06 J., 1919,115, 1380GENERAL AND PHYSICAL CHEMISTRY. 27given by Lewis and Randall86 for the same reaction usinggraphite, leads to C(amorph.) = C(graph.); - AF298 = 1700 cal.F. E. C . Scheffer, T. Dokkum, and J. Als7 obtain results by asimilar method which are in even better agreement with Saunders'sequation for the dissociation of methane and point out that, a tlower temperatures with a nickel catalyst, a carbide of nickel isformed which alters the equilibrium equation by changing theheat of reaction.R. W. Penning and H. T. Tizard 88 have investigated the dis-sociation of carbon dioxide at high temperatures and pressurescomparable with those obtained in internal combustion engines.The method employed was to explode standard mixtures of nitrogenand oxygen containing various amounts of carbon monoxide atconstant initial temperatures and pressures. In this way theywere enabled to determine the carbon monoxideoxygen ratiogiving the maximum pressure at any temperature, and could varythe temperature by varying the nitrogen-oxygen ratio.They findthat the carbon monoxideoxygen ratio has little effect on theexplosion pressure, thus indicating considerable dissociation ofcarbon dioxide under the conditions of their experiments (30 atm.pressure and 3000" K, approximately). Their results are expressedby the equationwhich gives results considerably lower than the accepted values,The usual procedure, the calculation of equilibrium data frommolecular heats and heats of reaction, has recently been reversedby W.G . Shilling,89 who has calculated the molecular heats ofnitrogen, oxygen, nitric oxide, carbon monoxide, carbon dioxide,and ammonia from considerations of various gaseous equilibria inwhich these gases participate. The results are in good agreementwith the accepted data.has investigated the thermal dissociation of carbony1 chloride at temperatures between 360" and 480" by twomethods, chemical analysis of the products of dissociation afterheating to a constant temperature, and physical measurement ofthe increase of pressure on dissociation under tho same conditions.It was found that the carbon monoxide and chlorine produced bythe dissociation were not equivalent when the carbonyl chloride washeated in glass vessels, and this was traced to the attack of the glasslog Kp = log p2co .p~,/p2co, = 8.46 - 28,60O/T,H. Ingleson88 " Thermodynamics," p. 672.87 Rec. trav. chim., 1926, 45, 803; A., 1927, 29.8 8 Proc. Roy. SOC., 1927, [ A ] , 115, 318.yo J . , 1927, 2244.Trans. Faraday Soc., 1926, 22, 377; A,, 1927, 1228 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.by the chlorine. Quartz vessels gave satisfactory results. A linearrelationship is found to exist between log K and 1/T, and a valueis deduced for the heat of dissociation at constant pressure of- 25,500 cal. in good agreement with the value obtained byThomsen. Little change in this value occurs with change oftemperature.P.G. Colin and H. V. Tartarm have investigated the form-ation of nitric oxide in the high-tension arc and agree with theview expressed by Daniels, Keene, and Manning that the " tem-perature " of an electric discharge has no thermodynamic significance,since some molecules become charged and accelerated by the fieldso that the Maxwell distribution of velocities is no longer obtained.In any case there is a region in the immediate vicinity of the dis-charge with a lower temperature, which, however, is still highenough to ensure rapid attainment of equilibrium. Provided thatthis temperature is taken as the thermodynamically significant one,the authors maintain that the law of mass action holds approx-imately for this reaction in the high-tension arc at pressures greaterthan half an atmosphere.It is considered that the equilibratedmixture is " frozen " so rapidly after leaving the arc that the useof water-cooled surfaces for this purpose is futile.Combustion and Flame.Considerable attention is being paid at present to radiation andionisation effects in combustion processes. W. A. Bone and hiscollaborators have greatly extended their work on gaseous explosionsat high pressures, following the course of the explosion by photo-graphically recorded tim*pressure curves. The marked differencebetween the rapid explosions of hydrogen-air mixtures as com-pared with the comparatively slow explosion of carbon monoxide-air mixtures at 50 atm. initial pressure was originally tentativelyexplained91 as being due to the fact that in the former case theenergy of reaction was released entirely in a kinetic (temperature)form, thus accelerating the reaction, which proceeded rapidly toequilibrium and was immediately followed by cooling by the wallsof the apparatus.In the second case, it was considered that thenitrogen absorbed some of this energy and stored it for a time in apotential form (activation), thus causing the reaction to proceedmore slowly, but that this energy was afterwards released in theform of heat, thus delaying the cooling. Subsequent work hasconfirmed this view in a striking manner. Mixtures of carbon90a J . Phyeical Chem., 1927, 31, 1539.QOb Trans. Amer. Electrochem. Soc., 1923, 44, 247.Dl Ann.Repom, 1923, 20, 20GENERAL AND PHYSICAL CHEMISTRY. 29monoxide and oxygen with no nitrogen present behave just likehydrogen-oxygen and the addition of small quantitiesof hydrogen to carbon monoxideair mixtures is suf6cient to changethe character of the explosion to the hydrogen-air type. Thislatter effect is explained by the theory that the hydrogen fist burnsto steam, which then oxidises the carbon monoxide so that none ofthe characteristic carbon monoxideoxygen radiations (which aloneare absorbed by the nitrogen) is emitted. This is further confirmedby experiments carried out by F. R. Weston93 on the spectra ofcarbon monoxide-air and carbon monoxide-hydrogen-air flames.The former show the characteristic blue colour and continuousspectrum of burning carbon monoxide, but as more hydrogen isadded the blue colour and the continuous spectrum disappear andsteam lines appear in the spectrum until, when equimolecular pro-portions of carbon monoxide and hydrogen are present, the appear-ance and spectrum of the flame are practically those of hydrogen.The effect of increasing initial pressure on the rapidity of theexplosion was further studied,94 and it was found that hydrogen-air and carbon monoxideoxygen mixtures show increasing rapiditywith increasing pressure, but that carbon monoxideair mixturesshow the reverse effect.This would be expected, since increase ofpressure increases the density and hence the absorbing capacity ofthe nitrogen present, and results in the fact that carbon monoxideair and hydrogen-air mixtures behave similarly a t lower pressures.Further evidence in support of the main hypothesis is obtainedfrom the observation 95 that, with excess air, carbon monoxide-airmixtures give quantities of oxides of nitrogen in excess of thethermodynamic yield calculated for nitrogen-oxygen mixturesalone. This would be expected if the carbon monoxide-oxygenreaction activates the nitrogen.Other diluents, except possiblyhelium,g6 have little or no effect on the carbon monoxide-oxygenreaction. Finally, direct confirmation of the theory was obtainedby a spectrographic examination of the ultra-violet radiationemitted during the explosion.97 Marked absorption was observedwhen nitrogen or excess carbon monoxide was present, and theabsence of bands due to oxides of nitrogen shows that the form-ation of these compounds is a secondary and later reaction.The92 W. A. Bone, D. M. Newitt, and D. T. A. Townend, Proc. Roy. SOC.,1923, [ A ] , 103, 205; d., 1924, ii, 398.93 Ibid., 1925, [ A ] , 109, 176, 523; A . , 1925, ii, 928; A., 1926, 8.94 W. A. Bone, D. M. hTewitt, and D. T. A. Townend, ibid., 1924, [A], 105,95 Idem, ibid., 1925, [ A ] , 108, 393; A., 1926, ii, 800.9 6 Idem, ibid., 1926, [ A ] , 110, 645; A., 1926, 480.406; A . , 1924, ii, 398.W. A. Bone and D. M. Newitt, ibid., 1927, [A], 115, 4130 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.experiments have been extended to the explosion of methane-oxygen rnixturesy98 and it is found that nitrogen is not activatedin this case.The results support the following scheme of reaction :-+ H,iC*OH 7- -+ H,:C:O + H,Ooxidation viaoxidation HGC: (OH),I +- 13.4 Oal.CO + H,IJ/- 22.8 Gal.CH4 TizxIJ.- 21*7 c + 2% CO + 2H,with the possibility of5 CH,*OH = 1 H, j + H, + COCH,*OH = j . .- :CH, - --___ I + H,Ooccurring a t lower temperatures. The main conc1usion.s obtainedfrom the above research have been confirmed by C. F. R. Harrisonand J. P. B a ~ f e r , ~ ~ who followed the course of the reactions bymeans of temperature measurements. W. E. Garner and C. H.Johnson1 have studied the effect of the addition of various sub-stances on the infra-red radiation emitted by the carbon monoxide-oxygen reaction. They find that small quantities of water, ethyliodide, or ethyl nitrate accelerate the explosion and depress theamount of infra-red emission, and that carbon tetrachloride andnitrogen peroxide have the opposite effect.They suppose that theacceleration of the reaction is caused by the conservation of theenergy within the system and that the dissipation of the energy byinfra-red radiation has the opposite effect. They propose the termenergo-thermic catalysis for this conserving phenomenon and suggestthe following scheme :infrct-red 2C0 4- 0, s internal += 2C02 + radiation2c0,[+energy 1+ X / \ +Y (energo-thermic catalyst)$2c0, 2c0, + infra-red radiation + thermal energyG. L. Wendt and F. V. Grimm employ Sir J. J. Thomson’s sug-gestion that an explosive flame is propagated by the emission ofelectrons from the reacting molecules and that the advance of theseelectrons before the flame front ionises and activates the unburntmolecules, ultimately causing detonation at high temperatures andpressures.They suggest that “ anti-knocks ” produce their effectss8 D. T. A. Townend, Proc. Roy. SOC., 1927, [A], 116,637; A., 1146.9s Phil. Mag., 1927, [vii], 3, 30.Ibid., p. 97.Ind. Eng. Chem., 1924, 16, 890GENERAL AND PHYSICAL CHEMISTRY. 31by removing these electrons. A considerable amount of work hasbeen done on this problem, and W. E. Garner 3 has summarised ourknowledge of explosion reactions from this point of view. Incollaboration with S. W. Saunders he has studied thermal ionis-ation in gas explosions and gas reactions.The Saha equationis applied to the ionisation of gases in explosions, and it is pointedout that, although the heat of ionisation (represented by the firstterm) may be as large as 350,000 cal. (corresponding to an ionis-ation potential of about 15 volts), yet, since the thermal energyliberated by chemical means during the explosion cannot be dis-tributed instantaneously amongst the molecules present, the Max-well distribution of energy may be momentarily disturbed andthere may be more molecules with large energy content than thelaw predicts. In effect, this implies a reduction of the energyrequired for ionisation, so that Kp will be larger than the Sahaequation predicts. In order to decide this point, measurementswere made of the electrical conductivity of exploding mixtures ofhydrogen and oxygen.6 It was found that the results agreed asclosely as could have been expected with the Saha equation, so thatlittle, if any, of the ionisation was due t o chemical energy suppliedas such and not thermally.The addition of anti-knocks was foundto diminish materially the electrical conductivity of such mixtures.S. W. Saunders finds that the increase of conductivity of anexploding mixture of hydrogen and oxygen in a spherical bomb isdirectly proportional to the distance travelled by the explosionwave in the firing tube. He suggests that this is caused by theincrease of ionisation consequent on the rise of temperature due tothe d u x of hot gases or flame from the firing tube.With K. Sat0 *he has studied explosions of carbon monoxideoxygen mixtures ina similar manner, and finds that the addition of hydrogen or waterto the dry gases materially increases the ionisation produced duringthe explosion, but that the duration of the ionisation is muchgreater when dry gases are used, this being in agreement with thelonger time of explosion (Le., the slower development of pressure)in this case. He has also investigated methane-oxygen andacetylene-oxygen mixture^,^ and finds that the maximum elec-trical conductivity occurs in the former case when the hydrocarbonis burned to carbon dioxide and water, and in the latter whenburned to carbon monoxide and water. J. A. J. BennettlO haslog Kp z= - 5048V.’/T + 2.5 log T - 6.56Trans. Famday Soc., 1926, 22, 263.Ann.Reports, 1923, 20, 5.6 Trans. Faraday Xoc., 1926, 22, 253.8 Ibid., p. 248.* Ibid., p. 281.’ Ibid., 1927, 23, 242.Ibid., p. 256. lo Ibid., p. 30732 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.measured the electrical conductivity of various flames, and hasstudied the effect of the addition of various substances thereon.He finds that, although ionisation accompanies detonation, it isnot related to it. This is confirmed by S. C. Lind,ll who agreeswith W. H. Charch, E. Mack, and C. E. Boord l2 that ionisationaccompanies, but does not cause, detonation.Ionisation has also been found to accompany slow combustion,13and J. A. J. Bennett and E. W. J. Mardlesl* have shown thatdetectable ionisation does not precede chemical change, and thatanti-knocks increase the temperature of first detectable ionisation.On this account they are inclined to favour the theory that per-oxides l5 are formed immediately prior to combustion, since thecomplete scission of the oxygen molecule required by the hydroxyl-ation theory might be expected to produce a more copious supplyof electrons.J. S. Lewis,16 however, finds that for paraffin hydro-carbon-air mixtures there exists a critical temperature at whichrapid chemical action takes place with an increase in the numberof molecules, and considers that his results support the hydroxyl-ation theory. A. Egerton and S. I?. Gates l7 find that anti-knocksdo not appreciably affect the detonation of acetylene-air or pentane-air mixtures a t ordinary or high temperatures and pressures (230”,10 atm.), but that they do retard the rate of slow combustion ofpentane.18 They point out that “knocking” is associated with avibratory form of combustion and not with detonation.SimiIarconclusions as to the effect of anti-knocks on the combustion ofhydrocarbons are reached by W. G. Lovell, J. D. Coleman, andT. A. Boyd.19The general conclusions appear to be that gaseous ionisation is athermal, and not a chemical effect, that there is little, if any, con-nexion between ignition temperature and ionisation, or betweenionisation and detonation, and that therefore Wendt and Grimm’shypothesis is a t fault.The law of flame speeds 20 has been reiterated by W. Paymanand R.V. Wheeler,21 but has been subjected to examination andl1 Trans. Paraday SOC., 1926, 22, 291.l2 Ind. Eng. Chem., 1926,lS, 334; B., 1926, 570.l3 J. A. J . Bennett, Trans. Paraday SOC., 1927, 23, 295.l4 J., 1927, 3156.l5 H. L. Callendar, Engineering, 1927, 123, 147.l6 J., 1927, 1555.l7 Proc. Roy. SOC., 1927, [A], 114, 137, 152; A., 318.l8 Ibid., 1927, [ A ] , 116, 516.2o Ann Repon%, 1922,19, 20.Ind. Eng. Chem., 1927, 19, 373.Trans. Famday SOC., 1926, 22, 301GENERAL AND PHYSICAL CHEMISTRY. 33severe criticism by W. A. Bone, R. P. Fraser, and D. A. Winter.22These authors conclude that it does not hold generally, since it isdemonstrably false for both slow- and fast-burning mixtures ofcomplex hydrocarbon, hydrogen, and oxygen (or air).In the samepaper, the validity of the suggestion23 that, with central ignitionin a spherical vessel, the maximum explosion pressure is developeda t the instant of contact of the flame front with the walls is ques-tioned. It would seem, however, that there is no doubt aboutthis fact, since 0. C. de C. Ellis and R. V. Wheeler 24 have pub-lished convincing photographs which show that, provided the flamefront travels quickly enough to eliminate convection effects, theinstants of maximum pressure and of flame contact with the wallsof a spherical vessel do coincide. With a cubical vessel undersimilar conditions, this result would hardly be expected, and it isfound in fact that pressure continues to be developed after con-tact. The same authors have studied ignition of gases in cylindricaland spherical vessels 25 and find in all cases a luminous region behindthe flame front.They ascribe this to the " after-burning " of com-bustible gas left behind by the flame front, and conclude that,although the explosion is complete at the instant of maximumpressure, the combustion process continues for some time afterwards.The Catalytic Catenary.Continuing their previous work 25a on the catalytic minimum-velocity point in the iodineacetone reaction, H. M. Dawson andhis co-workers 26 have obtained results supporting the " dual "theory of catalysis in an extended form. They have shown thatthe velocity of this reaction, when occurring in acetic acid-sodiumacetate b d e r solutions, is influenced, not only by the hydrogen-ionconcentration, but also by the concentrations of other ions andmolecules in the solutions. (The word concentration in this sectionmeans molar concentration uncorrected by any thermodynamicactivity factor.) The velocity equation then becomes :V = v h + Urn Vu + VOH = h[H'] -I- k m [ m ] + kJA-1 +kla[OH-] (1)terms for the hydrogen and hydroxyl ions, the acid anion, and theundissociated acid molecule entering the velocity equation, but the22 Proc.Roy. Soc., 1927, [A], 114, 420.28 J., 1923, 123, 1257.24 J., 1927, 153; compare J., 1925, 127, 760, 764.26 J., 1927, 310.26 H. M. Dawson and C. R. Hoskins, J., 1926, 3166; H. M. Dawson, J.,1927, 213, 458, 756, 1146, 1290; H. M. Dawson and W. Lowson, J., 1927,2107, 2444; H.M. Dawson and C. R. Hoskins, Proc. Leeda Phil. Lit. SOC.,1926,1, 108; A., 1927, 117.Ann. Reports, 1926,23, 86.REP.-VOL. XXIV. 34 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.metallic kation of the salt of the acid is without effect. If theacid concentration (c) in the buffer solution is kept constant and thehydrogen-ion concentration of the solution is sficiently great toallow the effect of the hydroxyl ion to be neglected, and assumingthat dissociation of the salt in the buffer mixture is complete and thatthe ionic dissociation of the acid (dissociation constant = R) followsthe simple mass law (again without activity factors), it can readilybe shown that the velocity is a minimum whenandfrom which it follows that the velocity-pH curve is symmetricalabout pHi.As the acid concentration is constant, the velocity dueto the ions alone is given byThis may be transformed to a general form by an application ofthe method used to obtain a reduced equation from a specificequation of state. Expressing [Hf] in terms of [H+]i([H+] = n[H+]i)and u in terms of ui (u = ruJ, an equation is obtained, r = u/Ui =&(n + l / n ) , between the reduced hydrogen-ion concentration andthe reduced ionic velocity, which, since log n = log [H+] -log [H+]i = pH8 - pH = A p H , becomes r = &(lod% + theequation to a catenary.This appears to be independent of the nature and concentrationof the catalysing acid, the nature of the solvent, and the nature ofthe reaction. Exactly the same equation is obtained by similarconsiderations applied to the catalytic effect of water and its ionsalone and, since in this case km is possibly very small compared withkoI1 and kh, the ionic velocity, u, is identical with the measuredvelocity v.The isocatalytic data in this case are obtained from( 2 ) and ( 3 ) by equating terms relating to HA to zero, and replacingterms in A- by terms in OH-, giving :andIn fact, there appears to be no valid reason for treating the hydroxylion in a different manner from other acid anions as regards itscatalytic properties.[H+J = d k , K ~ / ( k h - km) . . . . (2)Vi = 2 d ( k h - k,)kaKc + k,C . . . (3)u = ~h + VU = (kh - km)[H+] + kuKc/[H+][H+]i = dko,K,ja . . . . . (4)V i = SdkhkOHK, . - * ( 5 )If the ionic velocity equation be writtenit will be seen that u depends on [H+], ui, and [H+]i.Since thGENERAL AND PHYSICAL CHEMISTRY. 35last two are functions of the nature and the concentration of theacid alone, a complete representation of the equation is possible inthree dimensions. Taking u, pa, and c as the variables, and plottingrising values of ZL from bottom to top, rising values of p , from leftto right and rising values of c from front to back, the catalyticcatenary surface appears as a U-shaped valleyz7 with a definiteboundary to the left and in the front. The left-hand boundary ofeach section of the surface parallel to the u-pH plane (sections ofconstant c) terminates a t a point corresponding to salt-free acid,and at higher values of c ends obviously at lower pH values.Theprojection of these terminal points on the u-c plane is a paraboliccurve, whereas on the pH-c plane it is logarithmic. The valleybecomes narrower towards the back (as c increases), but the widthsof the valley sections measured at their left-hand terminal pointsare constant and depend only on the nature of the acid. Loci ofpoints of equal reduced hydrogen-ion concentration (reducedisohydric curves) run along the valley approximately from frontto back. The front termination of the valley is obviously thecatenary (c = 0) characteristic of the catalytic effects of hydrogenand hydroxyl ions. alone. Finally, the u-pE-c surface may betransformed into a v--rpH-c surface by lifting it vertically at each left-to-right section by an amount equal to knLc.If the conditions are such that the catalytic effect of the hydroxylions cannot be ignored, the mathematical treatment is the same,amounting in effect to the introduction of terms involving OH-and H20 corresponding to the terms in (2) and (3) which involveA- and HA. A compound catenary is then obtained with theisocatalytic dataandThere is thus a continuous series of compound catenaries of thisthird type between the H+-A- catenaries of the first type and theH+-OH- catenary, i.e., equations (2) and (3) represent the limitingcase for large acid concentrations, (4) and ( 5 ) for c = 0, and (6)and (7) for intermediate conditions.These considerations have been successfully applied to velocitymeasurements, not only of the iodinoacetone reaction, but also ofthe hydrolysis of ethyl acetate in acetic acid-sodium acetate buffers.T. M. Lowry and G. F. Smith z8 have applied them to the muta-rotation of dextrose and have found a small but measurable catalyticactivity in the kation of a weak nitrogenous base. T, M. Lowry 29[H+], = 2/(kaKc + hmKw)/(k> - L) (6)vi = 22/(k,' - Jcm)(kaKc + konliw) + krnc + Kwcw (7)2 7 J . , 1927, 756. 28 Ibid., p. 2539. 29 Ibid., p. 256436 ANNUBL REPORTS ON THE PROGRESS OF CHEMISTRY.has explained the catalytic effects of various ions and molecdes interms of an electrolytic theory. H. M. Dawson30 has pointed outthat the experimental results obtained by him and his collaboratorsare entirely at variance with the protion theory of catalysis advancedby F. 0. Rice,3l according to which the catalytic minimum of reac-tions affected by both the hydrogen and hydroxyl ions should liea t about pH = 5. Equation (4) shows that at a given temperature,and therefore at a fixed value of K,, the hydrogen-ion concentrationof the minimum point is determined by the ratio of the velocitycoefficients koH and kh. This ratio varies widely according to thenature of the reaction, and a variation of 1 : lo6 is by no meansextreme. This corresponds to a change in [H+]i of 1 : 1000, and toa change in the pH value of the isocatalytic point of 3 units. Theprotion theory has also been criticised on somewhat similar lines byM. Bergstein and M. Kilpatrick, j ~ n . , ~ ~ and by M. Bergstein.33HAROLD HUNTER.30 J . Physical Chem., 1927, 31, 1400; A., 1033.a1 Ann. Reports, 1926, 23, 36.J . Physical Chem., 1936,30, 1616; A., 1927, 214.83 Ibid., 1927, 31, 178; A., 321

ISSN:0365-6217    

DOI:10.1039/AR9272400011

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

INORGANIC CHEMISTRY.IN preparing the Report for 1927 it has been found, as in previousyears, that much work of interest and importance has perforce t obe omitted. Three subjects have been chosen for special con-sideration in the earlier paragraphs, and at the end of the Reporta list of the systems investigated during the year has been given.Otherwise, the scheme used in previous years has been followed.Valency.An important contribution to the theory of chemical combinationhas been made by N. V. Sidgwick in his Presidential Address toSection B of the British Association Meeting at Leeds. In additionto the generally accepted forms of linkage (a) electro-valent, inwhich electrons are transferred from one atom to another, and ( b )co-valent, in which the unit linkage consists of two shared electronsderived one from each of the linked atoms, he postulates a thirdform of linkage (c) co-ordinate, in which the unit linkage consistsof two electrons, shared in the manner characteristic of the co-valentlinkage, but both derived from one only of the linked atoms.Thissimple extension of accepted views explains all the peculiarities ofco-ordination compounds, of which the most important are theability of apparently saturated molecules such as water or ammoniato combine further, the existence of a valency limit (the co-ordinationnumber) independent of the Periodic Group to which the atombelongs, and the peculiar change in electro-valency that attendsthe replacement of a univalent radical such as chlorine by a wholemolecule such as ammonia.Although space precludes their detailed consideration here, it isextremely interesting t o follow these explanations and their furtherimplications, e.g., with reference to the mechanism of hydrolysisof the chlorides of the non-metals and the great stability of carbontetrachlpride, sulphur hexafluoride, etc.; these are fully and clearlyset out in the address and in the author’s book,l to which the readeris referred.N. V. Sidgwick, “ The Electronic Theory of Vdency,” Clarendon Press,Oxford, 192738 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Molecular Association.Remarkable results have followed from a new attack on theproblem of molecular association by the investigation of the effectof catalysts on the equilibrium between the complex and simplemolecules in a liquid.Acetic acid in contact with charcoal,platinum-black, or thoria had a vapour pressure greater than itsnormal value by 1-2 mm. of mercury. This difference in vapourpressure was increased after a period of heating and diminishedafter a period of cooling. The vapour pressure of benzene in con-tact with nickel was increased about 3 mm., that of methyl alcoholwith charcoal by 6 mm., and that of ether with charcoal by as muchas 40 mm., and other results of the same type have been obtained.Values for the molecular weights, calculated from surface-tensionmeasurements for liquids in contact with catalysts, seem to showthat, except in the case of acetic acid, the molecular complexity isincreased by heating the liquid for a short period, but is decreased bya longer period of heating.2 Similar changes have.been observed inthe density of water and ether when in contact with such catalystsas carbon and t h ~ r i a .~ There is no quantitative relation betweenthe vapour-pressure and surface-tension data, but this is hardly tobe expected, for the former depend chiefly upon the presence oflighter molecules in the liquid, while the latter tend rather tomeasure the complexity of the molecular species which accumulatesin the surface.In extension of the work on intensive drying, it has been foundthat nitrogen tetroxide, dried by repeated distillation over phos-phoric oxide, for a period of 4-6 months, has a vapour pressuregreater than the normal value by as much as 25 mm.After asudden change in the temperature of the dried material, thecorresponding change in vapour pressure was established slowly,several hours being required to attain a steady value.4 Newdata have been obtained for the vapour pressures of intensively-dried hexane, carbon disulphide, ethyl bromide, and nitrogenper~xide.~ Dried ammonium chloride has a vapour pressure lowerthan its normal value, and although internal transformations arenot inhibited, the equilibrium is shifted, the shift being greaterthe higher the temperature. These effects vanish above about310", and as the temperature is lowered association in the vapourbecomes appreciable at 286" and increases progressively.H. B. Baker, J., 1927, 949.8 J.B. Peel, P. L. Robinson, and H. C. Smith, Nature, 1927, 120, 614; A.,1019. 4 J. W. Smith, J . , 1927, 867; A., 506.A. Smits, 2. physikal. Chem., 1927, 129, 33; A,, 1027.Idem, Rec. trav. china., 1927, 46, 445; A., 819INORGANIC CHEMISTRY. 39Photosynthesis.The work on photosynthesis of organic compounds from carbondioxide and water, begun some years ago by Baly and his co-workers, has, during the past year, been brought to a stage ofquite extraordinary interest and importance. It has now beenshown that when aqueous carbonic acid is irradiated with ultra-violet light, a photostationary state is established involving, asone component, a complex aldehyde, the reaction being probably6H2CO,~C6H,,O,, + 60,. In attempting to assist the formationof carbohydrates by introducing a reducing agent, it was found thatferrous bicarbonate solution when irradiated deposited ferrichydroxide, and that organic compounds with reducing propertieswere simultaneously formed ; also, it was observed, the reactionoccurred primarily upon solid surfaces.Hence experiments weremade in which various insoluble solids capable of adsorbing carbondioxide (aluminium powder, barium sulphate, freshly precipitatedaluminium hydroxide, and the basic carbonates of aluminium,magnesium, and zinc) mere suspended in water through which astream of carbon dioxide was passed while the suspension, con-tained in tubes of quartz or Uviol glass, was subjected to the lightfrom a quartz mercury-arc lamp.Evaporation of the filteredsolutions yields organic residues, apparently of the nature of com-plex carbohydrates. Rigid proof was obtained that the materialsused were free from organic impurity, and negative results wereobtained in numerous control experiments. The most strikingand conclusive of these depended on the fact that aluminiumhydroxide, after a few hours, becomes unable to adsorb carbondioxide: thus, using the same tube, light, water, and carbondioxide, the same aluminium hydroxide when fresh gave the usualyield of carbohydrate, after 8 hours gave a small yield, and after24 hours gave no trace of organic residue.A discovery of still greater importance is that visible light maybe used in similar syntheses if the solid suspended in the solutionand capable of adsorbing carbon dioxide is coloured.Suitablesolids are nickel or cobalt carbonates, which must be free fromalkali, nitrate, chloride, and sulphate. In this case, one of theproducts is a carbohydrate which reduces Benedict’s solution,gives well-marked Molisch and Rubner reactions, and forms a solidosazone. The total quantity of material photosynthesised, and alsoits percentage reducing power, is greater than with a white surfacein ultra-violet light, probably because, with visible light, there islittle chance of photochemical decomposition of the products.There is, apparently, great similarity between these photochemicalprocesses and those in the living plant, e.g., in that-both sho40 ANNUAL REPORTS ON THE PROGRESS OF CHElKISTRY.similar fatigue effects and both give quantitative yields of the sameorder, and a possible mechanism of the process in vivo is advancedby the authors.' The further developments of this work will beawaited with interest,Atomic Weights.Argon.The most probable weight of a litre of pure argon hasbeen computed to be 1.7833 0.0001 g. ; whence the atomic weightA = 39.94 is deduced. Although appreciably higher than thatadopted by the German Commission (1923), this is regarded as aminimal value.8Potassium. Nephelometric determinations of the ratios KCl : Agand KCl : AgCl give as a mean of 31 concordant results, 0.691147 forthe former and 0.520186 for the latter ratio, whence K = 39-104 &0.0014.9 Conversion of potassium nitrate to the chloride by heat-ing in hydrogen chloride gives values for the ratio KNO,:KCl,from which, by the use of N = 14.008 and well-ascertained valuesfor the ratios AgCl : Ag and KCl : Ag, the following atomic weightsare calculated : K = 39.104 0.0007 ; Ag = 107.879 & 0.0011 ;C1 = 35,456 & 0*0003.10The value for silver (107.864 j, 0.0013) obtained by Bakerand Riley and previously reported l1 leads to values for chlorine(35.452) and nitrogen (13.999) which are regarded as improbable,and it has been suggested that the low value for the atomic weightcould be explained by losses of silver (about 0.1 mg.) occurringthrough the volatility of the metal at 1000°.12 In reply, Bakerand Riley have pointed out that their experimental conditionspreclude loss of silver, that there is no evidence of deposition ofsilver in the cooler parts of the apparatus, and that the silver,after repeated fusion within the apparatus, attained constancyin weight within 0.014-02 mg.They have also obtained directexperimental confirmation that loss of silver by volatilisation didnot occur.13The atomic weight of silver has been determined by reducingsilver nitrate with hydrogen. Errors due to adsorption of air on thesilver nitrate and on the reduced silver were eliminated by effecting7 E. C. C. Baly, 5. B. Davies, M. R. Johnson, and H. Shanassy, Proc. Roy.Soc., 1927, [A], 116, 197; -A., 1040; E. C. C. Baly, W. E. Stephen, andN. R. Hood, ibid., p. 212; A., 1041; E. C. C. Baly and J. B. Davies, ibid.,p. 219; A., 1041.Silver.* E.Moles, Ber., 1927, 60, [B], 134; A., 182.lo E. Zintl and J. Goubeau, ibid., p. 302; A., 806.l1 Ann. Reports, 1926, 23, 50.la B. Brauner, Nature, 1927, 119, 348, 526; A., 289, 493.la H. B. Baker and H. L. Riley, aid., p. 348, 703; A,, 289, 493.0. Honigschmid and J. Goubeau, 2. anorg. Chern., 1927,163,93; A,, 806INORGANIC CHEMISTRY. 41all weighings and the final fusion of the silver in a vacuum. Theatomic weight of nitrogen being taken as 14.008, ten highly con-cordant determinations give the value Ag = 107.879 & 0.0014.14In continuation of previous work on the variation in theatomic weight of boron derived from different thedensities of three samples of boron trichloride, portions of theoriginal materials used in the determination of the ratio BCI, : 3Ag,after further purification were compared by the flotation methodand the relative atomic weight of the boron in each was calculated.The collected results for the three samples of boron from California,Tuscany, and Asia Minor, respectively, are : by analysis, 10.841,104325, and 10.818 ; from densities of boric oxide, 104347, 104323, and10418 ; and from densities of boron trichloride, 10.830, 104325,and 104317.l6Scandium. Scandium chloride, prepared by passing carbontetrachloride diluted with nitrogen over the oxide at 750-850",purified by fractional sublimation, and weighed with special pre-cautions for the exclusion of moisture, has been used for a determin-ation of the ratio ScCl, : 3Ag.The mean of 9 analyses gave the valueSC = 45.160.l'Yttrium. Yttrium chloride, spectroscopically free from otherrare-earth metals, has been used for determinations of the ratioYCI3:3AgCl. The mean of 10 analyses gave the value Y =88.925 & 0-002.18Dysprosium. Similarly, dysprosium chloride, containing onlyabout 0.1% of holmium, has been used for 7 determinations of theratio to silver chloride, giving as a mean, after correction for theknown impurity, Dy = 162.459 & 0-004.19Lead. The constitution of ordinary lead has been investigatedby using lead tetramethyl in the mass spectrograph ; three principallines, 206, 207, 208, of intensities, respectively, 4, 3, 7, are in goodagreement with the accepted atomic weight, 207.2, and there is,also, a faint line at 209, and some evidence of lines at 203,204, and205.2QNitrogen.The average values for the densities of nitrogen a t 0"Boron.14 0. Honigschmid, 33. Zintl, and P. Thilo, 2. anorg. Chem., 1927, 163, 6 5 ;15 Ann. Reports, 1925, 22, 43; 1926, 23, 49.16 H. V. A. Briscoe, P. L. Robinson, and H. C. Smith, J., 1927, 282; A,,17 N. H. Smith, J . Amer. Chem. SOC., 1927,49, 1642; A., 806.18 0. Honigschmid and A. von Welsbach, 2. anorg. Chem., 1927, 165, 284;l@ Idem, ibid., p. 289; A., 915.80 F. W. Aston, Nature, 1927, 120, 224; A., 806.A,, 806.392.A., 915.B 42 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.and 253.33, 506.67, and 760 rum. pressure (at sea-level, in latitude45') have been accurately determined, and are 0.41667, 0433348,and 1.25036, respectively.If the value PV a t 1 atmosphere beunity, the values at 8 and Q atmosphere are 1.00011 and 1.00028,respectively, the average value of the coefficient of deviation fromBoyle's law between 0 and 1 atmosphere being -0.00045, a value inagreement with existing data. These results lead to the value14.007 for the atomic weight of nitrogen.21In a complete synthesis of silver chloride, chlorine,weighed as the liquid, was reduced to hydrogen chloride by meansof ammonium arsenite, and precipitated with a weighed quantity ofpure silver dissolved in nitric acid, and the silver chloride so formedwas weighed. As a mean of 9 determinations the ratio C1: Ag wasfound to be 0.328668, whence, if Ag = 107.880, the atomic weight ofchlorine is C1= 3.5~457.~~ Since the weight of silver chloridediffered from the weights of the constituent elements by less thanthe experimental error, doubts that have been expressed 22 as to thepurity of atomic-weight silver seem to be unfounded.It has further been shown that samples of hydrogen chloride,prepared from the extreme fractions obtained in a fractional dis-tillation of carbon tetrachloride, when used for determinations ofthe ratio Ag : AgCl gave substantially identical values, whence itappears that ordinary fractional distillation does not effect anyappreciable isotopic ~eparation.~~Saturated solutions of pure sodium chloride, prepared from fourdifferent samples of Alsatian potash minerals, differed in densityfrom one another and from a similar solution prepared from com-mercial salt by less than the experimental error ; thus any differencein the isotope ratio is too small to be detected by the methods used.24Chlorine.Group I .Much further work has been done on the reduction of aqueoussolutions of metallic salts by hydrogen under pressure.25 Crystallinehydroxides of aluminium and chromium have been prepared byheating solutions of the corresponding nitrate acidified with nitricacid to between 320-360", under a pressure of 200-370 atmospheres21 G.P. Baxter and H. W. Starkweather, Proc. Nat. Acad. Sci., 1926, 12,23 P. A. Guj7e and E. Moles, J. Chim. physique, 1917, 15, 360; A . , 1918,23 0. Honigschmid, S. B. Chan, and L. Birckenbach, 2. anorg.Chem.,24 (Mlles.) E. Gleditsch and L. Gleditseb, J. Chim.. physique, 1927, 24, 238 ;96 Ann. Reports, 1926, 23, 53.703; A., 1927, 194.ii, 40.1927, 163, 315; A,, 806.A., 493INORGANIC CHEMISTRY. 43of hydrogen, for 12-24 hours. The products resemble diaspore andchrome ochre, respectively. If air be used in place of hydrogen, theproduct is less crystalline and the yield is not quantitative, a portionof the oxide being converted into chromic acid.26 The action ofhydrogen on solutions of copper formate and acetate between90-180", a t pressures up to 150 atmospheres, and at acidities upto 12-5N, has proved interesting. I n neutral solution at loo",hydrolysis occurs with the separation of copper oxide, which isonly with difficulty reduced by hydrogen.The presence of acidrepresses this hydrolysis and the dissolved cupric salt is reduced tothe cuprous state. At moderate hydrogen-ion concentration, thecuprous salt is hydrolysed with precipitation of crystalline cuprousoxide, but here a.gain an increase of acidity inhibits hydrolysis andpermits further reduction to metallic copper. At higher temper-atures (130-180"), the anions decompose, yielding hydrogen whichcontributes to the foregoing reactions.27 Stannic hydroxide isreduced to the stannous state by hydrogen a t 300" and 38 atmo-spheres, and to the metal a t 350" and 50 atmospheres. Stannicsulphate at 302" and 162 atmospheres gives successively stannoussulphate and stannous sulphide : the reduction is retarded by thepresence of sulphuric acid or a sulphate.Stannic chloride isreduced to stannic oxide at 280-300" and 110 atmospheres, and tometallic tin a t higher temperatures. Addition of silver chloridegave, a t 380" and 260 atmospheres, mainly basic stannous chloride.28As with platinum, the production of metal by the action of hydrogenunder pressure on chloroiridate solutions a t 100" and 103" is greatestat low concentrations and increases with pressure, temperature, andtime. Under similar conditions, iridium is deposited more com-pletely than platinum. In cases of incomplete precipitation, ablue, unstable solution of colloidal iridium is produced .29A quantitative investigation has shown that the output of activehydrogen in a Siemens ozoniser, as measured by the reducingaction of the gas on sulphur, varies inversely as the rate of flow ofthe gas through the apparatus, varies directly with the pressure, andshows no linear relation to the voltage used, being negligible above70 mm.pressure and below 3000 volts.30 A thorough examinationof the processes previously stated to yield triatomic hydrogen leadsto the conclusion that there is no evidence for the existence of thissubstance. Hydrogen which has been passed through hot palladium,26 V. Ipatiev and B. Mouromtsev, Ber., 1927, 60, [B], 1980; A., 1043.2 7 V. Ipatiev and V. Ipatiev, jun., ibid., p. 1982; A,, 1042.28 V. Ipatiev and V. Niklaev, Compt. rend., 1927, 185, 462 ; A., 950.2Q V. Ipatiev and J. Andreevski, ibid., p. 357; A., 844.30 G. A. Elliott, Trans.Paraday SOC., Jan. 1927, advance proof; A., 18744 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.or submitted to a silent discharge in an ozoniser, and then passedover sulphur does indeed blacken lead acetate paper, but thesame effect is obtained if the passage over sulphur is omitted. Anumber of substances, including palladium, platinum, copper, andglazed porcelain, when heated in hydrogen at 600-700", yieldhydrogen sulphide, doubtless derived from a small sulphur contentin these substances : after prolonged treatment they cease to yieldhydrogen sulphide. This accords with the Reporters' experiencethat the most highly purified samples of magnesia contain a traceof sulphur, which is eliminated as hydrogen sulphide when themagnesia is heated to redness in hydrogen.Similarly, a glassozoniser which initially yields hydrogen sulphide ceases to do soafter it has been in use for a time. The ammonia supposed to beformed by the action of nitrogen upon hydrogen generated frommagnesium and acid has been shown to persist if no nitrogen isused and to arise, in fact, from the decomposition of magnesiumnitride present as an impurity in the magnesium. No reduction ofpermanganate or indigo could be obtained with the gas remainingafter exploding oxygen with excess of hydrogen, and it was shownthat hydrogen subjected to a-radiation from thorium-B andthorium4 did not thereafter reduce sulphur.31A new technique for the preparation of hydrogen peroxide hasbeen described, involving the decomposition of sodium peroxidewith 20% sulphuric acid, removal of sodium sulphate by crystal-lisation as decahydrate, and vacuum distillation under specifiedconditions. It gives a fair yield of 85% peroxide.32 It has beenshown that the decomposition of dust -free samples of hydrogenperoxide heated in smooth vessels is very slow, that solutionscontaining dust give linear decomposition curves, and that in-hibitors evidently act by poisoning the surfaces catalysing thedecomposition.33 By studying the change of pressure at constantvolume in a quartz bulb (the results in glass are not reproducible),it has been shown that the hydrogen peroxide vapour, admixed withwater vapour and oxygen, evolved from 60% aqueous hydrogenperoxide at 85", consists of simple non-hydrated molecules.Thethermal decomposition at 85" is a reaction of zero order, inhibitedby molecular oxygen ; so that the decomposition ceases when about20 yo of the hydrogen peroxide is dec~mposed.~~31 F. Paneth, E. KIever, and K. Peters, 2. Elektrochem., 1927, 33, 102;A., 429; M. Scanavy-Grigorieva, 2. anorg. Chem., 1926,159,55; A., 1927, 119.32 M. L. Kilpatrick, 0. M. Reiff, and F. 0. Rice, J . Amer. Chem. SOC., 1926,48, 3019; A,, 1927, 120.33 F. 0. Rice and 0. M. Reiff, J . Physical Chem., 1927, 31, 1352; A., 1035.34 L. W. Elder, jun., and E. K. Rideal, Trans. Paradav Xoc., 1927.23. 546;A,, 1038INORGANIC CHEMISTRY. 45Anhydrous lithium iodide decomposes at high temperatures in astream of oxygen according to the equation lOLiI + 502+-BLiIO, + 4Li20 + 412.35 A mono- and a tri-hydrate of lithiumchlorate are prepared by seeding solutions corresponding withLiC103,H20 and LiC103,3H,0 at -28" and -20", respectively, withcrystals of the hydrate 3LiC103,H20.36The colourless needles of sodium hydride prepared by directunion of hydrogen and sodium belong to the regular system, andX-ray examination by the Debye-iScherrer method shows that thecrystal lattice is probably similar to that of rock-salt. The dia-sociation of the hydride a t reduced pressures and at ordinarytemperatures is that to be expected with a solution of hydrogen insodium rather than a definite compound.At higher temperatures,however, the dissociation is accompanied by the separation ofsodium, free or almost free from hydrogen.,'A simple and convenient method for preparing small quantities ofpure potassium, rubidium, or czsium depends on the fact thatbarium azide, conveniently prepared by distilling azoimide intobarium hydroxide, decomposes a t ZOO"; so that if alkali chloridesare mixed with the azide in solution, and the solution is evaporatedto dryness in a vacuum, the solid residue on heating to a moderatelyhigh temperature yields a distillate of the alkali meta13*It has been found that the colours shown by a copper oxide filmmay be made truly homogeneous if special precautions are takenin the preparation and activation of the film.The study of suchfilms affords much evidence that the colours are produced byinterference in a thin layer of oxide.The order of production ofthe colours corresponds with the order tabulated by Rollet for theinterference colours of air films of increasing thickness seen bytransmitted light. It is found that the fall in electrical conductivityof the oxidised film supported on china clay is proportional to theequivalent air thickness of the oxide film, i.e., to the thickness of anair film which would producc the same colour as the copper oxidefilm. The equivalent air thickness is approximately proportionalto the quantity of metal oxidised. The wave-lengths of the maximain the absorption or reflexion bands in the spectrum of the light re-flected from the film move towards the red as the thickness increases,85 J. P. Simmons and C.F. Pickett, J . Amer. Chern. SOC., 1927, 49, 701;36 L. Berg, 2. anorg. Chern., 1927, 166, 231; A., 1042.37 G. F. Hiittig and F. Brodkorb, {bid., 1927, 161, 353; A., 529; compare** J. H. de Boer, P. Clausing, and G. Zecher, 2. anorg. Chem., 1927, 160,A., 429.Ann. Reportc~, 1926, 23, 63.128; A,, 32846 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.and the absolute thickness of the oxide film, calculated from thedensity and the mass of oxygen taken up per of the surface,agrees moderately well with the thickness calculated from theposition of the absorption band and the corresponding refractiveindex .39Curves connecting the absorption as a function of the compositionin solutions of cupric ion and ammonia in concentrated ammoniumnitrate, showed marked maxima, corresponding in the case ofequimolecular mixtures to the formula Cu(NH3),.For non-equimolecular solutions, the dissociation constant was calculated,and was found to agree with the result obtained from the absorptiondata. The tetra-ammonia ion, therefore, is probably the onlycupriammonia ion stable a t the ordinary temperat~re.~~ A com-plex thiosulphate, Cu,,S15018,9NH3, has been prepared by mixinga solution of sodium thiosulphate in concentrated ammonia withcupric chloride. The substance forms stable deep blue crystals.41Unsuccessful attempts have been made to discover the missingelement ,87 produced by the loss of an a-particle from mesothorium-2or as a P-product from radon.42Group I I .The process of dehydration of the hemihydrate of calcium sulphateabove 80" is reversible, but the dehydration does not take placespontaneously.Below 80", the water-vapour pressure of thesystem lies below 2 mm. of mercury. The decomposition of thehemihydrate into a mixture of dihydrate and anhydrous salt istheref ore thermodynamically impossible, as the regeneration ofthe hemihydrate could not take place. Such a decomposition ispossible only if two forms of the soluble anhydrous salt exist, vix.,an u-form stable below 72" and incapable of existence in equilibriumwith the hemihydrate, and a p-form stable above 72" and in thepresence of hemihydrate. Dilatometric measurements confirm theexistence of two forms : the transition a e p occurs a t 82", and isrendered evident also from the nature of the heating and coolingcurves, the p-form being produced from the a with the evolution ofheat.These facts constitute a probable explanation of contradic-tions in the literature concerning the crystal form of anhydrouscalcium sulphate .4339 F. H. Constable, Proc. Roy. SOC., 1927, [A], 115, 670; A., 930.40 P. Job, Compt. rend., 1927, 184, 204; A., 205.41 D. W. Horn and R. E. Crawford, Amer. J . Pharm., 1927, 99, 274; A.,42 G. von Hevesy, Kgl. Danske Videnskab. Selsk. math.-fys. Medd., 1926,43 D. Balarev [with A. Spassov], 2. anorg. Chem., 1927, 163, 137; A,, 829.634.7, No. 11, 1; A., 1927, 289INORGANIC CHEMISTRY. 47Large, violet mixed crystals of barium sulphate with potassiumpermanganate, which are not decomposed by oxalic acid in thepresence of sulphuric acid or by sulphurous acid, are obtained byallowing 2N-solutions of sulphuric acid and barium chloride todiffuse slowly into a 10% solution of potassium permanganate.'Doubt has been thrown upon the volatility of barium sulphatepreviously reported 45 on the strength of the observations that thesalt moistened with sulphuric acid colours the flame of a Bunsenburner green and that the flame obtained by igniting the vapoursfrom a heated mixture of barium nitrate, concentrated sulphuricacid, and methyl alcohol is also green.It has been suggested thatthe former coloration is due to the formation of a spray of finelydivided barium hydrogen sulphate or pyrosulphate, and in thesecond case it has been shown that the colour is probably due tomethyl nitrate, as similar colorations are obtained by substitutingstrontium or ammonium nitrate for the barium salt.46For the separation of radium from barium, the fractional pre-cipitation of the chromate in 0.05-0-3N-acid solutions is as efficientas the bromide method and is advantageous when only smallquantities of the mixture are a~ailable.~'The perchlorates, as drying agents, have been further in-~ e s t i g a t e d .~ ~ Barium perchlorate trihydrate on dehydrationin a vacuum a t 100-140" gives the anhydrous salt withoutfusing, and this equals sulphuric acid in drying efficiency. Amixture of barium perchlorate with up to 35% of magnesiumperchlorate can be dehydrated at 250" and 102 mm. pressure withoutfusing ; the granules of such a mixture containing 26.5% of mag-nesium perchlorate in a drying column 15 cm.long and 2.5 cm. indiameter allow only 0.001 g. of water to remain unabsorbed whenair 60% saturated with moisture is passed through for 5.5 hoursat the rate of 53 litres per hour. The mixture is, therefore, anextremely efficient drying agent .49Group I I I .Molten mixtures of a metallic oxide, boric anhydride or borax,and a fluoride, when electrolyaed with high cathode current densities,have yielded in a molten or crystalline state most of the metals with44 W. Geilmannand E. Wiinnenberg, 8. anorg. Chem., 1927,159,271 ; A., 120.4 5 F. Krauss, Chem.-Ztg., 1926, 50, 3 3 ; A., 1926, 368.46 F. L. Hahn, ibid., p. 934; B., 1927, 106; compare Krauss, ref.45;4 7 1;. M. Henderson and F. C. Kracek, J . Amer. Chem. SOC., 1927, 49, 738;4 ~ 3 Compare Ann. Reports, 1922, 19, 45.49 G. F. Smit,h, I n d . Eng. Chem., 1927, 19, 411; A., 438.F. Krauss, ibid., 1927, 51, 38; B., 139.A., 43148 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.heats of oxidation less than that of sodium.50 A similar methodhas been applied to the production of boron, the mixture 2B,03 +MgO + MgF, being used a t 1100", in a charcoal crucible which actsas anode, the cathode being an iron rod. The cathode deposit,consisting of boron agglomerated by the solidified electrolyte, isground and extracted with hydrochloric acid, giving a 95% yield ofboron of 92 yo purity.51The constitution of the hydrides of boron, discovered by Stockand his coLworkers 52 and formulated by them on the assumptionthat the valencies involved were 3 and 4, has been reviewed byseveral authors.It is suggested that a more satisfactory explanationof the compounds may be based on the assumption that the valenciesare 3 and 5 and the co-ordination number 4. On this basis, B,H,would be formulated H3B:BH3, the ammonia compound either asthe salt (H,B:BH,--)(NH,+), or, less probably, H,B:NH,, andthe hydride B,H1, as H,B:BH,*BH,:BH,. The comparativelygreat stability of hydrides with 6 , 6, and 10 boron atoms is mostsatisfactorily explained by the adoption of ring formulae as follows :BH,=FH, BH,:BH:BH, BH,:BH-$*BH,:BH,hH ,*BH*BH, BH,:BH:hH, BH,:BH,*B*BH=BH,Formula (I) accounts for the fact that B,H, combines with 4molecules of ammonia to give B,H,(NH,),, which with hydrogenchloride evolves 4 molecules of hydrogen rapidly and a further 3molecules more slowly. The naphthalene structure of (111) is inagreement with its chemical properties and its high melting point.53Electronic interpretations of the constitution of the boron hydrideshave been advanced by Ulmann and by Main Smith.54Investigations of the freezing point of boric acid solutions, andof the solubility of the acid in water in the presence of variousproportions of hydrogen peroxide, together with the conductivityof these solutions, have thrown little or no light on the constitutionof the acid, but conductivity measurements show that the mono-borates are binary electrolytes and give no evidence of a ternarydissociation corresponding with formule of the type M,B,O,.- +(1.1 (11.) (111.)5O Andrieux, Compt.rend., 1927, 184, 9 1 ; A., 216.61 L. Andrieux, ibid., 185, 119; A,, 844.6a Compare Ann. Repork, 1926, 23, 68.64 M. Ulmann, Ber., 1927, 60, [BJ, 610; A., 399; but see A. Stock, Ber.,1927,60, [BJ, 1039 ; A., 714, who regards these explanations as unsatisfactory ;see also E. Muller, ibid., p. 1323; compare E. Miiller, 2. Elektrochem., 1925,31, 382; A., 1925, ii, 841; J. D. Main Smith, Chem. News, 1927, 135, 81;A., 813.J. A. Christiansen, 8. anorg. Chern., 1927, 160, 395; A., 399INORGANIC CHEMISTRY. 49Concentrated solutions of the corresponding diborates apparentlycontain B40," ions, rather than univalent diborate ions.For moredilute solutions, the experimental data are compatible with adecomposition of the diborate into monoborate and free boric acid.In concentrated solutions, the perborates behave as ternary elec-trolytes, giving the ion 2B0,,2H20~", whereas dilute solutionsapparently contain the ion B02,H202 . The fact that pentaboratesgive unusually high values for van 't Hoff's coefficient, i, is ascribedto a very considerable decomposition of the pentaborate ion, B,O,',into less complex ions and boric acid, which occurs even whenconsiderable excess of boric acid is added.55 The literature relatingto those borates of the alkali metals which can be crystallised fromaqueous solution has been critically reviewed, and X-ray diagramsand dehydration experiments have shown that the removal of thelast molecule of water from the hydrates of sodium monoborate isaccompanied by a change in the structure of the crystal.Withthe diborate it is apparently the last three water molecules whichare of structural importance, but the pentahydrate stable above 60"appears to occupy an exceptional position.56A large number of fluoroborates have been prepared, analysed, anddescribed; those of the heavy metals appear to be characterised bytheir great solubility, deliquescence, and instability at highertemp erat~res.~'A new scaly variety of aluminium hydroxide, A1,0,,4H20,d31' 1.5490, soluble in mineral acids, has been produced by thereduction of barium nitrate solution with the aluminium-mercurycouple at 0".One molecule of water is lost a t loo", and the lastmolecule, with difficulty, a t a red heat.58A vigorous discussion continues as to priority in the discoveryof element No. 61, but this can hardly be summarised here.S9 Itis more important to note that attempts to increase the amountss H. Menzel, 2. anorg. Chern., 1927, 162, 1, 22; A., 937.H. Menzel [with J. Meckwitz], ibid., 166, 63; A., 1043.67 E. Wilke-DSrfurt and G. Balz, ibid., 159, 197; A., 120; H. Funk andF. Binder, ibid., 1926, 159, 121; A., 1927, 219.HZ P. Neogi and A. K. Mitre, J., 1927, 1222; A., 741.69 W. Prandtl and A. Grimxn, 2. angew. Chem., 1926,39,1333; A., 1927, 9;L. Rolla and L. Fernandes, Gazzetta, 1926, 56, 688; A., 1927, 9; idem, 2.anorg.Chem., 1926, 157, 371; A., 1927, 31; R. Brunetti, Atti R. Accad.Lincei, 1926, [vi], 4, 518; A., 1927, 190; L. Rolla and L. Fernandes, Gaxzetta,1926, 56, 862; Atti R. Accad. Lincei, 1926, [vi], 4, 498; A., 1927, 190;R. Brunetti, ibid., p. 515; A., 1927, 190; W. A. Noyes, Nature, 1927, 119,319; A., 296; R. Brunetti, 2. anorg. Chem., 1927, 160, 237; A., 296; L.Rolla and L. Fernandes, ibid., p. 190; A., 296; W. A. Noyes, Nature, 1927,120, 14; A., 714; L. Rolla and L. Fernandes, Gazzetta, 1927, 57, 290; A.,611; B. S. Hopkins, J. Franklin Inst., 1927, 204, 1; A., 81450 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.available for X-ray exasmination have resulted in the production of asample containing about 1% of the element which gave seven linesof the L-series of illinium.6*Scandium acetylacetonate and salts of the types M3(ScF6) andK,[M(C,O4),],5H2O strongly resemble those of the tervalent elementsof the iron family, and further evidence of this analogy is afforded bythe preparation of the new compounds, which are isomorphous withthe corresponding compounds of the iron family :Samarous chloride has been prepared b y reducing the anhydroustrichloride in a mixture of ammonia and hydrogen a t 750".It formsa mass of dark reddish-brown needles, m. p. 740", readily soluble inwater to a solution which, on keeping, evolves hydrogen and depositsan insoluble oxychloride. The intense colour of the dichloride mayserve to detect samarium in the presence of large quantities of otherearths.62 A number of new compounds of europium have beendescribed, including the oxalate, nitrate, normal and hydrogentartrates, acetate, citrate, acetylacetonate, iodate, carbonate, and~yanoplatinate.~~ The ammoniates of the chlorides of lanthanum,cerium, praseodymium, and neodymium have been prepared andobservations made of their decomposition temperatures and of thecontraction in volume attending their formation.64Gallium has been used in a fused quartz thermometer which maybe employed to measure temperatures up to 1000".The removal ofgas from the liquid gallium and the effect of impurities on theamount of undercooling and on the tendency to wet quartz havebeen investigated. The ease of surface oxidation of gallium isgreater than is represented in the l i t e r a t ~ r e .~ ~Group I V .The vapour pressure of carbon suboxide (C30,) has been measuredbetween -62" and 4", giving a calculated b. p. a t atmosphericpressure of 6.8" and a heat of vaporisation of approximately 6 kg.-cal. The pure gas is very stable in contact with dry, clean glass,but decomposes in contact with mercury or glass contaminated withthe polymerised form.6660 J. M. Cork, C. James, and H. C. Fogg, Proc. Nut. Acad. Sci., 1926, 12,61 G. Urbain and P. B. Sarkar, Compt. rend., 1927, 185, 593; A., 1010.62 G. Jantsch, H. Riiping, and W. Kunze, 2. unorg. Chem., 1927, 161, 210;63 M. P. B. Sarkar, Bull. SOC. chim., 1927, [iv], 41, 185; A., 326.64 F. Ephraim and R. Block, Ber., 1926, 59, [B], 2692; A., 1927, 121.65 S.Boyer, J . Opt. Xoc. Amer., 1926, 13, 117; A, 1927, 100.66 M. J. Edwards and J. M. Williams, J . , 1927, 865; A,, 506.696; A., 1927, 190.A., 530INORGANIC CHEMISTRY. 51A brown solid, having the composition C,O,,xH,O, has beenproduced by circulating carbon monoxide, a t 20-69 cm. pressureand continuously freed from carbon dioxide, through a Siemensozoniser actuated by alternating electric current of the order of20,000 volts per cm. a t 250 cycles per second. This substance wasvery hygroscopic, reacted with water, giving approximately 1 mol.of CO, per mol. of C,O,, and formed a solution containing oxalicacid (1 mol. per 3 mols. C,O,), colloidal particles, and a dark; in-soluble residue.67A long series of experiments on the catalytic synthesis of hydro-cyanic acid from nitric oxide and hydrocarbons a t high temper-atures has led to the general conclusion that the first stage in thereaction is the reduction of nitric oxide to ammonia, part of whichreacts to form hydrocyanic acid, whilst part dissociates into hydrogenand nitrogen.Ethylene decomposes gradually, giving methane,hydrogen, and carbon, but acetylene and highly unsaturatedhydrocarbon residues (CH,= and CHZ) are probably intermediateproducts. The formation of hydrocyanic acid is then completed bythe action of ammonia either on ethylene or on one of these inter-mediate products. It is unlikely that solid carbon plays anyappreciable part in the reaction. Carbon monoxide is probablyproduced by the interaction of ethylene with the water vapourformed in the reduction of nitric oxide.6sThe reactions of alkali thiocyanates which have been stronglyacidified with sulphuric acid differ greatly from those of the neutralsalt.Thus ferric salts give a red colour which rapidly disappears,wliilst the white precipitates obtained with silver, lead, and mercurysalts slowly become yellow, and cobalt nitrate yields a green precip-itate of perthiocyanogen, (HC,N,S,), with traces of cobalt saltsand of perthiocyanic acid, (H,C,N,S,). When acids (preferablynitric acid) are added to a solution containing two or more thio-cyanates, precipitation of a complex thiocyanate of definite com-position may result. The precipitate must be collected immediately ;otherwise a violent reaction may take place after a few minutes,with the decomposition of the precipitate and evolution of oxides ofnitrogen, sulphur dioxide, hydrogen cyanide, etc.The compoundsHgCo(CNS) (blue) (which may be used as a fairly delicate qualitativetest for mercuric ions), PbBi(CNS), (red), and possibly CdHgBi( CNS)(red) have been obtained by this meth0d.6~Pure silicon has been prepared by interaction of pure silicontetrachloride vapour and hydrogen at the surface of a glowing67 R. W. Lunt and R. Venkateswaran, J., 1927, 857; A., 531.6 8 E. Elod and H. Nedelmann, 2. Elektrochem., 1927, 33, 217; A., 838.B. Ormont, 2. anorg. Chem., 1927, 161, 337; A., 53152 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.carbon filament 0.3 mm. thick, maintained at 1000" by an electriccurrent.The product has a metallic appearance, is very stable inair, and appears to become more brittle as the temperature rises.The coefficient of linear expansion between 18" and 950" is 3.55 x; the electrical conductivity increases with rise in temperature.?OThe absolute density and coefficient of thermal expansion ofsilicon tetrachloride have been found to be 1.481475 & 0*0,68/20"and 0*0014044 5 0*0687/20", respectively.71Pure germanium, prepared by reducing specially purifiedgermanium dioxide with hydrogen and graphite, has m. p. 959" inhydrogen, 958" in carbon dioxide, and 975" in a vacuum; it isvolatile in hydrogen at atmospheric pressure below SOO", and in avacuum below 760". Molten germanium (1 g.) absorbs hydrogen(0.1839 g.) on cooling and reduces germanium dioxide to the mon-0xide.7~ The metal has also been prepared by reduction of thedioxide with carbon under a flux of sodium chloride in a graphitecrucible heated in an induction furnace.73The formation of complex compounds of stannic and stannousiodides with other metallic and organometallic halides has beenextensively investigated, and a number of stable compounds havebeen reported.74The specific heats at 8-13" of chemically and physically purewhite and grey tin are reported as 0.0537 r f 0.0003 and 0.0493 &-0.0002, respectively,75 and the transition temperature of the twoforms is found to be 13".76 It has also been shown that the metalheated at 350" for some minutes gives a calorimetric curve withoutdiscontinuities, whilst if heated at 500" for 2 hours, it gives a curveshowing a sharp break a t 170-171", which is accentuated by in-crease in time or temperature.The dependence of such results onthe previous thermal treatment of the metal, irrespective of itspurity, explains the anomalous results previously obtained. 77Croup v.The view that active nitrogen is a metastable molecular formwith an energy of about 42,500 cal. per g.-mol. (Le., approximately7O R. Holbling, 2. angew. Chem., 1927, 40, 655; A., 844.7 1 P. L. Robinson and H. C. Smith, J., 1926, 3152; A., 1927, 102.72 J. H. Muller, E. F. Pike, and A. K. Graham, Proc. Amer. Phil. SOC.,73 (Miss) K. M. Tressler and L. AT. Dennis, J . Physical Chem., 1927, 31,74 T.Karantassis, Ann. Chim., 1927, Ex], 8, 71; A., 950.75 E. Cohen and K. D. Dekker, 2. physikal. Chem., 1927,127, 183; A,, 818.7 6 Idem, ibid., p. 178; A,, 818.7 ' A. Travers and Huot, C m p t . rend., 1927, 184, 162; A., 194.1926, 65, 15; A., 1927, 121.1429; A., 1046INORGANIC CHEMISTRY. 532.0 volts) '* is said to be difficult to reconcile with the spectroscopicA study of the reactions of active nitrogen with othergases of varying critical increments, confirmed the energy givenabove as a mean value, but was held to show that the gas containsthree species of active molecules, some having energies just aboveand others energies just below the mean value.8O From laterexperiments, the conclusion is drawn that the glowing and chemicallyactive forms of nitrogen are distinct, the former being due to re-combination of atoms with a heat of formation of 250,000 cal./g.-mol., and the latter, which possesses an energy of about 45,000cal./g.-mol., may be metastable molecular nitrogen or a more complexsubstance such as N3.81 The decay process, presumably of thisform, in contact with metallic filaments is bimolecular and gives anenergy value of 46,000 cal./g.-mo1.82 On the other hand, a study ofthe electrical behaviour of glowing active nitrogen indicates that itis molecular nitrogen in a metastable state with an energy between9.4 and 10.4Sodium azide when rendered unstable thermally in an atmosphereof oxygen is converted almost quantitatively into sodium nitriteand nitrogen.Catalysts or carriers are unnecessary, but the presenceof free alkali is essential to delay the transformation 3NaN-Na3N + N, until the oxygen molecule can penetrate the nitrogenzone.Oxidising agents such as copper oxide, manganese dioxide,and lead dioxide merely facilitate the remoyal of nitrogen byoxidising the sodium, whereas peroxides such as barium peroxidehave the same effect as gaseous oxygen, since they furnish molecularoxygen. It therefore appears probable that the direct combustionof ammonia to nitrite and subsequently to nitrate at a basic contactdepends on an unstabilising of the molecule, prior to thermal dis-sociation, which may be represented by the scheme HN-H,;molecular oxygen then penetrates the molecule and displaceshydrogen, which is subsequently oxidised to water.In a similarmanner, hydrogen converts sodium azide into nitrogen and sodamide,the greater velocity of diffusion allowing it to penetrate the nitrogenzone so rapidly that the presence of alkali is not necessary to preventthe transformation 3NaNzzr+ Na,N + N,. If sodium azide isdecomposed in an atmosphere of carbon dioxide, the NaN:::residues unite with loss of nitrogen and production of sodiumnitride, which is very readily hydrolysed to sodium hydroxide78 Ann. Reports, 1926, 23, 65.79 R. C. Johnson, Nature, 1927, 119, 9; A., 85.*O E. J. B. Willey and E. K. Rideal, J., 1927, 669; A., 431.s1 E. J. B. Willey, Natwe, 1927, 119, 924; A., 635.88 E. J. B. Willey, J., 1927, 2188; A., 1038.83 P. A. Constantinides, Phy&al Rev., 1927, [ii], 30, 95; A., 91654 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.and ammonia, even when the concentration of aqueous vapour isvery l0w.84The behaviour of nitrogen tetroxide and trioxide in a number ofadditive compounds with tin and titanium tetrachloride, chosenbecause the co-ordination number is invariably six, has led to thediscovery of certain new compounds stable only at low temperaturesand to the conclusion that the oxides may best be representedrespectively as (O:),N*O*N:O, and O:hT*O*N:0.85 A study of thethermal decomposition of nitrogen pentoxide in the presence offoreign gases has shown that hydrogen, carbon monoxide, andbromine are without influence, but that certain organic vapoursbring about rapid, almost explosive, reaction ; whilst nitric oxide isoxidised immediately.Hydrogen and air have no 'effect on thephotochemical decomposition, but bromine, possibly by opticalscreening, retards it. The mechanism of the decomposition is con-sidered to be N,05--+N0 + NO, + 0, (slow); NO + N205+3N0, (rapid).86Since the reaction 4NO + 30, + 2H,O + 4HN0, involves adiminution in volume, attempts have been made to use nitric acid asa carrier of oxygen present a t a high pressure. In this way, withoxygen at 20 atm., sodium nitrite has been oxidised to nitrate andarsenious oxide has yielded arsenic acid; but no change took placein the absence of nitric acid. The method has been applied withsuccess to arsenic sulphides, which are converted into arsenic acidand sulphuric acid.87Nitrogen sulphide has been prepared by passing ammonia mixedwith air into an anhydrous benzene solution of sulphur dichloride.It had m.p. 179", d 2-2, and M 184-3, corresponding to the acceptedformula N4S4. It sublimes near the melting point and explodesa t higher temperatures. Its solubility in various solvents and itsreactions with water, acid, and alkali, respectively, have been fullyinvestigated. The structural formula suggested as according bestwith its properties is S:S(:N*SiN),.s8It is only possible here to refer to papers on the chemiluminescenceof phosphorus vapour 89 and on the nature of the ions produced byglowing phosphor~s.~~ Pure crystalline phosphorus tri-iodide,84 K. A. Hofmann and U. Hofmann, Ber., 1926,59, [B], 2574; A,, 1927, 31.8 6 W.F. Busse and F. Daniels, J. Amer. Chern. SOC., 1927, 49, 1257; A,,8 7 P. Askenasy, E. Elod, and H. Zieler, 2. anorg. Chem., 1927, 182, 161;68 S. A. Vosnessenski, J . Rum. Phys. Chern. SOC., 1927, 59, 221 ; A,, 741.H. Reihlen and A. Hake, Annalen, 1927, 452, 47; A., 219.635; compare R. G . W. Norrish, Nature, 1927, 119, 123; A,, 119.A,, 635.E. J. Bowen and E. G. Pells, J., 1927, 1096; A., 633.W. F. Busse, Ann. Physik, 1927, [iv], 82, 873; A., 633INORGANIC CHEMISTRY. 55m. p. 61.0", and di-iodide, m. p. 124.5", have been prepared.g1Besson's supposed suboxide, P20, has been shown to be a mixture offinely divided amorphous phosphorus with adsorbed phosphorousa ~ i d . ~ 2 It has been shown that a variable mixture of phosphorussulphides is formed when phosphine is heated with sulphur or withhydrogen s ~ l p h i d e .~ ~The glow of arsenic in air or oxygen, which appears suddenly attemperatures between 250" and 310" when the pressure is reducedbelow a critical value, differs from that of phosphorus, since it is notaffected by small quantities of carbon tetrachloride, nitrobenzene,or sulphur dioxide. The appearance of the glow is favoured by arapid removal of the arsenic trioxide formed in the reaction, and itis suggested that the velocity of removal of the product by evapor-ation and condensation is the determining factor in the formationof theAn extensive research is reported on the oxides of antimony,and a new oxide, Sb,O,, is described which is very stable and maybe heated for a long period a t 800" without decomposition; oncedecomposition has begun, however, it proceeds rapidly a t lowertemperatures.The paper contains much thermal and vapour-pressure data which cannot be summarised here.95Investigations of tervalent vanadium 96 and of the action ofhydrogen peroxide on acidified solutions of vanadic acid have beenmade.97croup V I .The fact that the density of solid oxygen a t -252" is 0.034 unitgreater than the accepted value (wix., 1.46) affords additional evidenceof the existence of a second, denser form of solid oxygen stable a ttemperatures much lower than the melting point. The existence oftwo forms of oxygen accords with the properties of other membersof the same group.gsWhen mixtures of sulphur and chlorine are heated at 100" insealed tubes, or with the addition of a trace of iodine as catalyst, theproduct gives a freezing-point curve showing, in addition to thefamiliar maxima due to the crystallisation of S2C12 and SCl,, twowell-defined breaks which are attributed to the crystallisation ofF. E.E. Gemann and R. N. Traxler, J . Arner. Chem. SOC., 1927, 49, 307 ;A., 328.92 L. J. Chalk and J. R. Partington, J., 1927, 1930; A., 950.VS L. Delachaux, Helv. Chirn. Acta, 1927, 10, 195; A., 326.94 H. J. Ernelkus, J., 1927, 783; A., 497.O 5 A. Simon and E. Thaler, 2. anorg. Chem., 1927,162, 253; A., 730.g6 J. Meyer and E. Markowicz, ibid., 1926, 157, 211 ; A., 1927, 32.97 J. Meyer and A.Pawleth, 2. physikal. Chem., 1927, 125, 49; A., 326.g * J. C. McLennan and J. 0. Wilhelm, Phil. Mug., 1927, [vii], 3, 383; A,,29756 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.SCl, and S3C14. Freshly prepared mixtures of sulphur mono-chloride with an equilibrium mixture containing about 70% ofchlorine exhibit a maximum freezing point at the compositionSCI,, and a solid of this composition is obtained on freezing.99It has been shown that the burning of sulphur vapour in oxygengives rise to sulphur trioxide; this is formed by direct union andnot by a secondary oxidation of sulphur di0xide.lThe molecular weights of the various forms of sulphur trioxidehave been determined in various solvents and by measurementsof vapour density.2 Because negative catalysts such as sulphur,tellurium, carbon tetrachloride, and phosphorus oxychloridestabilise the a-form of sulphur trioxide, it is suggested that it hasthe structure S( :0)3, whilst the p-form, disulphuric anhydride, hasthe constitution 0 0>S<g>S<g.3A long and very important paper has appeared on the inter-relationships of the sulphur acids; it contains so much valuabledetail that it cannot usefully be summarised here, and the reader isreferred to the original communication.A new anhydro-acid,H,S,O,, is described which is oxidised by methylene-blue to tetra-thionic acid. The acid results from one of the three possible modesof decomposition of thiosulphuric acid : H,S,03 e H , S 0 3 + S ;2H,S,03 H,S +- H2S306 ; 2H2S,03 H,O + H2S405.4Sulphur trioxide readily reacts with nitric oxide a t 60", yieldingthe product 2S03,N0, m.p. 215-220' after darkening and softeninga t 180", b. p. 275"/715 mm. The substance is readily decomposedby water into sulphuric acid and nitric oxide, but does not react withferrous sulphate or cupric sulphate dissolved in concentratedsulphuric acid. When heated, it decomposes into sulphur dioxideand nitrogen peroxide, from which it may be prepared a t 200-300".If, however, the gases are moist, nitrosylsulphuric acid is formed inwhich drops of " blue acid " appear after some time. The " acid "is regarded as an oxide of nitrogen intermediate between NO,.,and NO. Raschig's conception that " blue acid " has the composi-tion H,SNO, is rendered improbable by the observation that itsabsorption spectrum does not resemble those of the compoundsCuSO,,NO and FeS04,N0.599 T.M. Lowry, L. P. McHatton, and G. G. Jones, J., 1927, 746; A., 505.1 J. Cornog, W. Dargan, and P. Bender, J. Amer. Chem. SOC., 1926, 48,G. Odd0 and A. Casalino, Gazzetta, 1927, 57, 60, 76; G. Oddo, ibid.,G. Odd0 and A. Sconzo, ibid., p. 83; A., 432.4 H. Bassett and R. G. Durrant, J., 1927, 1401; A,, 843.W. Manchot [with J. Konig and S. Reimlinger], Ber., 1926, 59, [B], 2672;2757; A., 1927, 32.pp. 29, 104; A,, 312, 300, 432.A., 1927, 32INORGANIC CHEMISTRY. 57If the solution, obtained by the action of carbon monoxide onmagnesium ethyl in the presence of chromic chloride is hydrolysedwith sulphuric acid at 0", and the ethereal layer is separated,neutralised, dried: and evaporated, crystals of chromium carbonyl,Cr(CO),, separate.The pure carbonyl has dlS* 1.77, is slightlysoluble in benzene and ether, but more soluble (2%) in chloroformand carbon tetrachloride, decomposes rapidly into chromic oxidea t 210", melts in a sealed tube at 149-150", and irreversibly depositsa chromium mirror a t 230". The carbonyl is unattacked by diluteacids, bromine, and iodine; fuming nitric acid converts it intochromic nitrate and free carbon.6Molybdenyl monochloride, MoOC1,4H20, has been shown to existin two stereoisomeric forms,' and the behaviour of the othermolybdenyl salts has suggested that in certain circumstancesoxygen may occupy two positions in the co-ordination sphere.8 Alarge number of hydrated molybdotungstates have been preparedand analy~ed.~Selenium oxyfluoride and tetrafluoride, both colourless, fumingliquids, have been prepared, and there is some evidence that alower fluoride, Se2F,, may exist.1° Attempts to repeat theproduction of selenium trioxide previously reported l1 have beenunsuccessful.12Group V I I .The oxidising action of fluorine on water, alkali hydroxide,sulphuric acid, phosphoric acid, phosphates, carbonates, andborates gives highly oxygenated compounds of the peroxide, peracid,or ozonide type in most cases.13 Passage of fluorine into a fairlyconcentrated solution of cobaltous sulphate in sulphuric acid yieldscobaltic sulphate, which is extremely unstable : the cobaltic salt isformed only with difficulty in dilute s01utions.l~A gaseous, oxygen compound of fluorine is produced when wateris present in the electrolysis of molten acid potassium fluoride below100".The gas has not been prepared in the pure state, but studiesof its mixtures with oxygen point to the formula F,O. Such mixtures6 A. Job and A. Cassal, Bull. SOC. chim., 1927, [iv], 41, 1041; A., 1044.7 W. Wardlaw and R. L. Wormell, J., 1927, 130; A., 296.8 Idem, ibid., p. 1087; A., 636.9 L. Fernandes, Bazzetta, 1926, 56, 655; A., 1927, 33.10 E. B. R. Prideaux and C. B. Cox, J., 1927, 928; A., 532.11 Ann. Reports, 1923, 20, 52.12 J. Meyer and A. Pawletta, Bey., 1927, 60, [B], 985; A., 532.13 F. Fichter and W. Bladergroen, Helv. Chirn. Acta, 1927, 10, 549, 653,1 4 F. Fichter and H.Wolfmann, Helv. C h h . Acta, 1926,9, 1093; A., 1927,559, 566 ; A., 741.12358 ANNUAL REPORTS ON TEE PROGRESS OF CHEMISTRY.have the odour of fluorine, do not act on glass even at high temper-atures, are stable in the presence of water, but liberate iodine frompotassium iodide.15A compound, K,Mn(CN)3, containing univalerit manganese, hasbeen produced by the reduction of potassium manganocyanide byaluminium filings or Devarda’s alloy; it has very strong reducingproperties.16Group V I I I .A number of salts have been described in which cobalt and nickelare believed to be univalent,17 and a description has been given ofthe preparation and properties of certain perferrates. Potassiumperferrate is more stable than potassium ferrate and can be purifiedby cautious sublirnation.l*The passivity of iron has been shown to be due to the existence ofa protective film which is too thin to give interference tints.Thisfilm, which consists of ferric oxide or hydroxide, has been obtained asa transparent envelope by dissolving the metal beneath by anodictreatment in sodium chloride solutions. The transparent skin canalso be removed by treatment with iodine. Chlorides favour theactivation, since the film is permeable Do chloride ions, and underanodic conditions the metal is dissolved away beneath the skin;mere immersion in a chloride solution, under conditions precludingthe flow of local currents, does not cause activation. The attack onpassive iron is often localised a t the water surface, the protectivefilm tending to cling to the gas-liquid rather than to the metal-liquid interface, thus initiating a breakdown.Nitric acid is a ratheruntrustworthy reagent for producing passivity. Transparentfilms have also been isolated from the surface of passive copper andaluminium. l9Differences of density and viscosity in a series of aqueous solutionsof cobalt chloride and hydrochloric acid show when plotted awell-marked inflexion and maximum respectively, which are con-sidered to mark the concentration of acid a t which equal numbers ofthe blue and the red ions are present. This point does not correspondt o the maximum colour change because the blue of CoCl4” is moreintense than the red of C O ( H ~ O ) ~ * * .~ ~ Other workers prefer toP. Lebeau and A. Damiens, Compt. rend., 1927, 185, 652; A., 1044.W. Manchot, ibid., 1926, 59, [Bj, 2445; A., 1927, 33; G. Grube [withH. Lieder and P. Schiichterle], 2. Elektrochem., 1926, 32, 561 ; A., 1927, 119.D. K. Goralevitch, J . Russ. Phys. Chein. SOC., 1926, 58, 1129; A,, 1927,433.l6 W. Wanchot and H. Gall, Ber., 1927, 60, [B], 191; A., 220.Is U. R. Evans, J., 1927, 1020; A., 619.0. R. I-Iowell, J., 1927, 158; A., 205INORGANIC CHEMISTRY. 59explain the change in terms of complex formation, and compoundsof the type CoCl,,H,O (blue or violet), CoC1,,4H20 (red), andCoCl,,GH,O (rose) are postulated.21Ruthenium dichloride and dibromide have been produced byreducing the tri-halogen salts with hydrogen in suitable organicsolvents in the presence of catalysts, and their properties have beenfurther described.22 The structure of Wilm’s rhodium chloronitratehas been investigated and the following formula has been suggested:[ ~ ~ [ R h & 6 ] ~ ~ ~ ] SH4.23Systems.A great deal of work has been done on various types of, systemswhich it is impossible to describe in this Report.It may be useful,however, to give here the titles, in the order in which they appear inthe Abstracts.Potassium zincicyanide-potassium mercuricyanide-potassiumnickelocyanide-potassium cadmicyanide 24 ; mercuric chloride-silver iodide 25 ; lanthanum sulphate-ammonium sulphate-water 26 ;beryllium chloride-chloride of lead or silver or cadmium 27 ; sodiumnitrate-sodium chloride-water ; sodium oxide-nitrogen pentoxide-water 29; sodium, or potassium, or rubidium or cEsium chloride-cobaltous chloride-water 30 ; magnesium sulphatezinc sulphate ;lithium chloride or bromide-water 32 ; zinc hydroxide-zinc oxide-sodium zincate-sodium hydroxide 33 ; lithium chlorate-water 34 ;2 1 A.Hantzsch, 2. mzorg. Chem., 1927, 169, 273; A., 205; compare J.Gr6h and R. Schmid, ibid., 162, 321; A., 728; A. Hantzsch, ibid., 166, 237;A., 1023.22 H. Gall and G. Lehmann, Ber., 1926, 59, [B], 2856; A., 1927, 123.23 0. E. Zwiagincov, J. Russ. Plqs. Chem. SOC., 1926, 58, 170; A., 1927,24 A. S. Corbet, J., 1926, 3190; A., 1927, 112.25 A. G. Bergman and T. A. Henke, J . Russ. Phys. Chem. SOC., 1926, 58,z 6 F. Zambonini and (Miss) A. Stolfi, Atti R. Accad. Lincei, 1926, [vi], 4,2 7 J. M. Schmidt, Bull. SOC. chim., 1926, [iv], 39, 1686; A., 1927, 112.28 F. Hold a2nd H. Crotogino, 2. anorg. Chem., 1926, 159, 78; A., 1927, 207.e9 W. T. Nikolaiev, J. Russ. Phys. Chem. SOC., 1926, 58, 557; A., 1927, 3138so H. W. Foote, Amer. J . Sci., 1927, 13, 158; A., 313.31 H. G. K. Westenbrink, Proc. K. Akad. Wetensch. Amsterdum, 1926, 29,3a.G. F. Huttig and W. Steudemann, 2. physikul. Chem., 1927, 126, 105;a3 E. Muller, J. Muller, and A. Fauvel, 2. Elektrochem., 1927, 33, 134; A.,34 C. A. Kraus and W. M. Burgess, J. Amer. Chem. Soc., 1927, 49, 1226;123.80; A., 1927, 112.424; A., 1927, 112.1374; A., 1927, 417.A,, 617.518.A., 62760 ANNUAL REPORTS ON THE PROGRESS O F CHEMISTRY.carbon disulphide-hydrogen sulphide 35 ; manganese-zinc 36 ;calcium f errocyanide-sodium f errocyanide-water 37 ; barium iodide-iodine-water 38 ; sodium chloride-potassium chlorate-sodiumchlorate-potassium chloride 39 ; potassium oxide-ammonia-phos-phorus pentoxide-water 40 ; cobalt chloride-rubidium or lithium orzinc or cadmium chloride-water 41 ; uranyl sulphate-ammoniumor potassium or sodium sulphate-water 42 ; copper-aluminium-manganese 43 ; iron-silicon 44 ; iron-cobalt-nickel45 ; neodymiumsulphate-rubidium sulphate-water 46 ; silver nitrate-lithium orrubidium nitrate 47 ; neodymium sulphate-ammonium sulphate 48 ;cerium sulphate-sodium sulphate 49 ; aluminium nitrate-water 50 ;sodium or lit,hium chloride-lead chloride-water 51 ; boron trioxide-sulphur trioxide or phosphorus pentoxide-water .52H. V. A. BRISCOE.P. L. ROBINSON.36 W. Biltz and M. Briiutigam, 2. anorg. Chem., 1927, 162, 49; A., 627.36 C. L. Ackermann, 2. MetaZZk., 1927, 19, 200; A, 627.38 A. C. D. Rivett and J. Packer, ibid., p. 1342; A., 731.39 C. Di Capua and U. Scaletti, Cazzetta, 1927, 57, 391 ; A., 731.40 E. Jiinecke, 2. physikal. Chem., 1927,127, 71; A., 731.41 A. Benrath, 2. anorg. Chem., 1927,163, 396; A., 829.42 A. Colani, Compt. rend., 1927, 185, 273; A., 830.43 W. Krings and W. Ostmann, 2. anwg. Chem., 1927, 163, 145; A., 830.44 T. Murakami, Sci. Rep. Tdhoku Imp. Univ., 1927, 16, 475; A,, 830.4 5 T. Has& ibid., p. 491; A., 830.d6 F. Zambonini and V. Caglioti, Atti R. Accad. Lincei, 1927, [vi], 5, 630;47 A. P. Palkin, J . Russ. Phys. Chem. SOC., 1926, 58, 1334; A., 1927, 939.48 F. Zambonini and A. Stolfi, Atti R. Accad. Lincei, 1927, [vi], 5, 832;** F. Zambonini and S. Restaino, ibid., p. 828 ; A., 940.6O G. Malquori, ibid., p. 892; A., 949.51 G. E. R. Deacon, J., 1927, 2063; A., 1030.62 31. Levi and L. F. Gilbert, ihid., p. 2117; A., 1030.(Miss) M. Farrow, J., 1927, 1163; A., 628.A., 842.A., 949

ISSN:0365-6217    

DOI:10.1039/AR9272400037

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

ORGANIC CHEMISTRY.PART ALIPHATIC DIVISION.Alcohols, Aldehydes, and Ketones.THE action of fused alkali hydroxides at 250-300" upon ethylalcohol is slow and several reactions appear to take place simultan-eously, sodium carbonate, oxalate and acetate, hydrogen, methane,and ethylene being produced. Acetaldehyde under similar con-ditions at 250" reacts to the extent of 90% in accordance with theequation C,H,O + NaOH+NaOAc + H2. Higher temperaturespromote the formation of methane and sodium carbonate :C,H,O + BNaOH-+H, + CH4 + Na,CO,. Acetone was foundto behave like acetaldehyde.1Several communications have appeared dealing with the structureof the acetylenic y-glycols. In one of these2 a study is made ofthe physical properties and reactions of pc-dibromo-pc-dimethyl-Ar-hexinene and of the product resulting from the action of phos-p horus t ri bromide on p E - dimet h yl- A7 - hexinene- PE - diol . The crys t a1 -line dibromide, m.p. 39", previously obtained by G. D~poni;,~ iscomparatively inert and appears to possess the ethylenic structureCMe,:CBr*CBr:CMe, and not Dupont's acetylenic structure. Theglycol on treatment with phosphorus tribromide gives a mixture ofproducts, amongst which is a less stable isomeric dibromide, m. p.46-48", which probably possesses the acetylenic formulaCMe,Br*CiC*CMe,Brand passes easily into the ethylenic isomeride. Other varieties arepresent, however, and the reaction is apparently complex. Theseconclusions are in essential agreement with the results obtainedin another investigation of the same problem,4 with the exceptionthat in the latter case the acetylenic dibromide, m.p. 4648", wasfound to be comparatively inert. The action of hydriodic acidon the glycol effects conversion into a crystalline di-iodide, C,H,,12,H. S. Fry and E. L. Schulze, J . Amer. Chem. Soc., 1926, 48, 958; A.,W. N. Krestinski, J . Russ. Phys. Chem. Soc., 1926, 58, 1067; A,, 1927,Compt. rend., 1911, 152, 197; A., 1911, i, 173.J. S. Salkind and M. P. Sigova, J . Russ. Phys. Chem. SOC., 1926, 58.1926, 710.442. See also Ber., 1926, 59, [B], 1930; A., 1926, 1121.1039; A., 1927, 44262 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.m. p. 75", analogous in structure t o the ethylenic dibromide,5 andthe investigation has been extended to include the action of hydro-bromic acid on one of the stereoisomerides of as-diphenyl-AB-butinene-as-diol.This gives a complex mixture of products,amongst which are two solid dibromides, a solid tribromide, aliquid dibromide and a liquid monobromide. A detailed study ofthe properties of each of these shows that the monobromide, forwhich the formula CH-cHPh>O I I is suggested, yields no di-bromide on further bromination, and the dibromides must thereforebe formed by means of an independent parallel reaction. To thedibromide, m. p. 114-1 15", the structure CHPh:CBr*CH:CPhBris ascribed, and the isomeric dibromide, m. p. 92-95", may be eitherCHPhBr*CiC*CHPhBr or CPhBr:CH*CH:CPhBr.Oleyl alcohol (n-trans-At-octadecen-a-01) has been converted viathe liquid bromine additive compound, which is then treated withsilver acetate in acetic acid, into the diacetate of oleicerin (n-trans-octadecane-atK-trio1). The free trio1 obtained on hydrolysis is asolid, m.p. 126.5". The corresponding n-cis-octadecane-awtriO1(elaidicerin, m. p. 92") may be prepared in a similar way fromelaidyl alcohol.'A further addition to the number of organic compounds con-taining fluorine has been made by the preparation of trifluoro-tert.-butyl alcohol from isoamyl trifluoroacetate by reaction withmagnesium methyl iodide, the fluorine remaining unattacked.The alcohol (m. p. 20.8") may be converted by treatment withphosphorus pentabromide, but not with concentrated sulphuricacid, into yyy-trifluoroisobutylene, which combines without loss offluorine with hydrogen bromide and with bromine.8A study of the absorption curves in ultra-violet light.of acetalde-hyde and paracetaldehyde solutions indicates the presence of anenolic form of the aldehyde, the proportion being 1 in 335 foracetaldehyde in sodium hydroxide, 1 in 530 in hydrochloric acid,and 1 in 1045 for paracetaldehyde in hydrochloric acid.9The enolisation of acetone has been investigated by means ofthe compound (CH,:CMe*O*),HgY2Hg0 obtained from freshly pre-cipitated mercuric oxide and acetone in the presence of potassiumhydroxide. It appears that the cnolisation of acetone is analogousCBrCHPh5 J. S. Salkind, B. Rubin, and A. Kruglov, ibid., p. 1044; A., 442.6 J. S. Salkind and A.Kruglov, ibid., p. 1052; A., 443; Ber., 1926, 59,7 E. Andre and (Mlle.) T. Frangois, Compt. rend., 1927, 185, 387; A., 957.8 F. Swarts, Bull. SOC. chim. Belg., 1027, 36, 191; A, 443.9 8. A. Schob, Cornpt. rend., 1927,184, 1452; A., 751.1936; A., 1926, 1121ORGANIC CHEMISTRY.-PART I. 63to that of ethyl acetoacetate, a maximum amount of the enolicmodification being formed in the presence of 0.037df-alkali, furtherincrease in the alkali concentration being without effect .loThe action of bromine (1 mol.) on paracetaldehyde a t low temper-atures gives bromoparacetaldehyde, m. p. 27.5", together with thedibromo-compound. The former decomposes when heated a t 130"into bromoacetaldehyde. The reaction between bromine (3 mols.)and paracetaldehyde is complicated by the action of hydrogenbromide on the aldehyde, which leads to the formation of tetra-bromobutaldehyde. In all these changes very slight evolutionof hydrogen bromide occurs and the mechanism of the reactionis said to depend on an equilibrium between paracetaldehyde andacetaldehyde, the latter of which becomes enolised under theinfluence of bromine to give vinyl alcohol.The very unstableah-dibromoethyl alcohol is then formed, which passes into tribromo-paracetaldehyde and hydrogen bromide. The liberated acid maycombine with acetaldehyde or vinyl alcohol, yielding a-bromoethylalcohol, which with a p-dibromoethyl alcohol gives a mixture ofmono- and di-bromoparacetaldehyde 11 in accordance with thetwo equations :2CH2Br*CHBr*OH + CH,*CHBr*OH + C6Hlo03Br2 + 3HBrCH,Br*CHBr*OH + 2CH,*CHBr=OH --+ C6Hl10,Br + 3HBrBromination of polymerised aldehydes at low temperatures hasbeen employed as a means of obtaining a-hydroxy-aldehydes.Thus parapropaldehyde with bromine (1 mol.) at -lo", followedby treatment with alcohol, gives the acetal of a-bromopropaldehyde,which when hydrolysed with water yields a-hydroxypropaldehyde.Similarly from the acetals of aa-dibromopropaldehyde and a-bromo-heptaldehyde, pyruvaldehyde and a dimeric form of a-hydroxy-heptaldehyde were obtained.12 A study of the complex reactionbetween magnesium ethyl bromide and a-bromo-aldehydes revealsa certain similarity in behaviour between the latter compoundsand acyl halides.For instance, a-bromoheptaldehyde and mag-nesium methyl bromide give a very small amount of y-bromo-P-octanol, together with methyl hexyl ketone, a tertiary alcohol(probably (3-methyloctan-p-ol), and an olefine, C9H18, which resultsfrom dehydration of the tertiary alcohol.Lead hydroxide anda-bromoheptaldehyde give heptoic acid in place of the expectedlo W. L. Evans and W. D. Nicoll, J. Amer. Chem. SOC., 1925, 47, 2789;A., 1926, 51.l1 A. Stepanov, N. Preobraschenski, and M. Schtschukina, Ber., 1926, 59,2533; A., 1927, 42. Compare also R. Dworzttk, Monatsh., 1925, 46, 253;A., 1926, 385.la R. Dworzak and P. PfiEerling, Monatsh., 1927,48, 251 ; A., 105564 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.aldehyde-alcohol, and it is thus probable that the methyl hexylketone is formed by molecular transformation during the actionwith the magnesium methyl bromide, the reaction thereafterresembling that with an acyl halide.13The chemical properties of glyceraldehyde and of dihydroxy-acetone are of special interest in view of the importance of thesecompounds both in physiological processes and as simple hydroxy-compounds related to the aldoaes and ketoses.A. Wohl's method l4of preparing glyceraldehyde has been improved and a detailedexamination of the dl-compound has been commenced.15 Duringthe isolation of dl-glyceraldehyde from its diethylacetal a viscousopaque syrup can be obtained which possesses unexpected properties.It is definitely enolic in character, and is unimolecular in aqueoussolution, whereas the crystalline variety is bimolecular and inaqueous solution contains only a trace of the enolic modification.The enol appears to be present also in an alkaline solution of crystal-line glyceraldehyde and, since this enol is identical with the enolicmodification of dihydroxyacetone, an explanation readily followsof the mechanism of acrose formation from glyceraldehyde, theessential reaction being the aldol condensation of glyceraldehydeand dihydroxyacetone.The transformation of bimolecular glycer-aldehyde into dihydroxyacetone in yields up to 49% has beeneffected by treatment with boiling pyridineI6 and on the basisof this and other evidence, such as the indifference of the acetatetowards phenylhydrazine and the non-formation of an isopropyl-idene ether, the formula ( O<cH.cH2.0H)2 is suggested.Thediethylacetal of glyceraldehyde, on the other hand, reacts readilywith acetone to form the isopropylidene ether.The action of hydrobromic acid in acetic acid on diacetylglycer-aldehyde gives the bimolecular acetobromoglyceraldehyde, m. p.QH*OH168-169", to which the formula ( O<CH.CH,.0Ac)2 QHBr is ascribed.Methyl alcohol and silver carbonate give the correspondingacetylated methylcycloacetal, from which bimolecular glyceralde-hyde methylcycloacetal, m. p. 158.5-159.5", may be obtained by1 YH-OMethe action of ammonia in methyl alcohol, (O<cH.cQoH),.The very close resemblance between these reactions and the corre-sponding properties of acetobromoglucose is further shown by thel3 A.Kirrmann, Compt. rend., 1927,184, 1463 ; A., 751.14 Ber., 1898, 31, 1796, 2394; A., 1898, i, 655; 1899, i, 11.l5 H. G. Reeves, J . , 1927, 2478; A., 1172.18 H. 0. L. Fischer, C. Taube, and E. Baer, Ber., 1927, 60, 479; A., 340ORGANIC CHEMISTRY .-PART I. 65transformation of acetobromoglyceraldehyde to bimolecular acetyl-glyceraldehyde, m. p. 118.5'. Some similar bimolecular compoundshave been obtained from glycollaldehyde (e.g., glycollaldehydemethylcycloacetal, m. p. 72"), and from dihydroxyacetone, whichgives the met hylc ycloacetal CH,. OH] , m . p . 1 3 1- 1 32 O . l7The elucidation of the particular type of polymerisation foundin the dimeric compounds may be expected to yield results ofimportance both for this and for other fields of investigation.A convenient method for the preparation of isopropylideiieethers depends on the use of anhydrous zinc chloride as condensingagent in dry acetone solution.18 The ethers thus prepared aremore stable than those obtained by the aid of acids, and of themany substances treated by this method only d-glucose showed anabnormal behaviour.The process is specially valuable as a meansof isolating dihydroxyacetone.A general method for the preparation of ketone-alcohols of thetype CHPh(OH)*COR is that of acting on phenylglycollamide or thecorresponding nitrile with magnesium alkyl halides. Secondaryalcohols of the type CHPhROOH are, however, always formed asby-products in the case of the nitrile.19 The preparation of theketone-alcohols CHPh(0H)-COR, in which R = ethyl, propyl,isopropyl, n-butyl, isobutyl, and benzyl, is described.It has beenfound that a-keto-alcohols, when heated in alcoholic solution at120-130" with a small quantity of sulphuric acid, undergo molecularrearrangement. The carbonyl group moves so as to take up aposition as near as possible to the end of the chain, the tendencybeing for the formation of an acetyl group. Thus butyrylethyl-carbinol is transformed into propionylpropylcarbinol. The sugges-tion is made that a similar transformation may play a part in thecourse of alcoholic fermentation.20A detailed criticism has been contributed of the formulaCH,(OH)*O*SO,Na assigned by E. Knoevenagel21 to the sodiumhydrogen sulphite addition compound of formaldehyde. Thestability of the addition compound towards oxidising agents, itsready reducibility, and its reaction with phenols to give sulphonicacids are all incompatible with the above formula and evidenceof the direct attachment of sulphur to carbon is provided.Ammonial7 H. 0. L. Fischer and C. Taube, Ber., 1927, 60, 1704; A., 857.l 8 Idem, ibid., p. 485; A., 338.lo M. Tiffeneau and (Mlle.) J. Levy, BUZZ. SOC. chim., 1925, 37, 1247; A*,1926, 71.A. Favorski, ibid., 1926, 39, 216; A,, 1926, 600.21 Ber., 1904, 37, 4060; A . , 1904, i, 1027.REP.-VOL. XXTV. 66 ANNUAL REPORTS ON TRE PROGRESS OF CHEMISTRY.reacts with formaldehyde hydrogen sulphite to give a compoundwhose properties show it to be aminomethanesulphonic acid andfurthermore formaldehyde bisulphite and ethyl acetoacetate may bemade to yield ethyl a-sulphomethylacetoacetate,COMe-CH( CH,*SO,H)*CO,Et,which is hydrolysed in alkaline solution to P-sulphopropionic acidand in acid solution to y-ketobutanesulphonic acid.It is shownthat the change is not explicable on the grpunds of initial fissionof the aldehyde bisulphite with the addition of sulphurous acid a ta later stage. The attachment of both hydroxy- (or amino-) andsulphonic groups to the same carbon atom confers a special labilityon each, which is responsible, in addition to other reactions, forthe ready loss of the latter group as sulphur dioxide. In the secondof the two papers referred to, a wealth of experimental evidence iscited to support the formulation of formaldehyde bisulphite a.ssodium hydroxyme t hanesulphonate, CH, (OH) *S 03Na .*2Carbohydrates.Monosaccharides, Lactones, and G1ucosides.-The revision of thestructural formulze of the most commonly occurring forms ofglucose, reported last year, has received wide acceptance, and thegeneralisation which accompanied this revision has passed intocommon use in the formulations applied to the carbohydrate group.Corifirmatory evidence of the nature of the oxide rings in derivativesof the normal and also of the labile or y-sugars has been furnishedfrom many sides, and this evidence has now assumed so convincinga character as to place the issue beyond any reasonable doubt.There is still need for reform in the nomenclature adopted to definethe structural relationships of the sugars, and a paragraph on thisproblem at the end of the present sub-section reports on some recentsuggestions.A comparative study of ten methylated lactones derived fromsimple sugars has shown that the rate of hydrolysis of five lactonesobtained from normal sugars is many times greater than in the caseof the remaining five lactones, which are related to the y-sugars.%The curves showing the change lactone acid reveal well-markeddifferences in the stability of the lactones as between the two types.Those derived from normal sugars are seen to be %lactones havingsix-membered rings, whereas those related to y-sugars are y-Iactoneshaving five-membered rings.Six of the series of ten lactones are22 F.Raschig, Ber., 1926, 59, 859; A., 1926, 699; F. Raschig and W.Prahl, Annalen, 1926, 448, 265; A,, 1926, 939.23 H. D. K. Drew, E. H. Goodyear, and W. N. Haworth, J., 1927, 1237;A,, 750ORGANIC CHEMISTRY .-PART I. 67crystalline and others give characteristic phenylhydrazides whichare crystalline. It is possible to diagnose by these methods whichmember of a pair of related lactones belongs to the &type and whichto the y-type, and since these substances are obtained from sugarsby a simple oxidation which does not involve degradation or otherprofound change, the ring-structure of a sugar derivative can bereadily determined.In many cases the lactones have been submitted to oxidativedegradation to the dibasic acids. The characterisation of thesedegradation products by direct comparison with authentic referenceproducts hss furnished confirmation of the structural formul=which had previously been a.llocated to the lactones on the basisof the physical studies outlined above.Examples of this kindmay be quoted. The crystalline sugar, tetramethyl glucose (I),obtained by methylation methods from a- or p-methylglucoside,yields a tetramethyl S-gluconolactone (11) which suffers degradationwith hot nitric acid. The chief product of this change has beenrecognised 2* as xylo-trimethoxyglutaric acid (111), which gives acrystalline methylamide identical with that prepared 25 by oxidisingthe %lactone (IV) obtained from the trimethyl xylose (V) which isderived from the usual form of methylxyloside.I $‘H*OH{H-OH 1 Q0,H .p , H H*T*OMe[FHoOMe]4 ? [QH*OMe], --+ [yH*OMel4 MeO-7-HCH, -A CH,OH C02H H*y*OMe 1(VI.1 (VII.) (VIII.) CH,-’(V. )It is conceivable that (111) might arise from the direct oxidationof a tetramethyl sugar of formula (VI), but this is much less likelyto be so if the intermediate stage is recognisable as a lactone, sincethe existence of an c-lactone is extremely doubtful. This possibility24 W. N. Haworth, E. L. Hirst, and E. J. Miller, J., 1927, 2436; A., 1173.2 5 W. N. Haworth and D. I. Jones, ibid., p. 2340; A., 105968 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.is, however, entirely negatived by the experimental observation 26that the monobasic acid of a substance corresponding to (VI) hasbeen prepared, namely, 2 : 3 : 4 : 5-tetramethyl gluconic acid (VII),and this does not form a lactone, nor does it oxidise to the dibasicacid (111); under the same conditions as those adopted for thedegradation of (11) to give (111), it passes into tetramethyl saccharicacid (VIII).It is represented that there can be no other interpret-ation of these results than that the tetramethyl glucose is correctlyformulated by (I) and that a- and p-methylglucosides possess a six-membered (amylene-oxide) ring. That the free a- and P-glucoseshave the same oxide-ring structure seems more than probable.Referring now to the two aldohexoses galactose and mannose, aconfirmation is given that the usual forms of methylgalactoside andalso a-methylmannoside correspond to the same structural classific-ation as the two normal forms of methylglucosides (a- and p-).Crystalline tetramethyl galactose (IX) yields on oxidation tetra-methyl 8-galactonolactone (X), the constitution of which is nowverified 27 by degradation to the Z-arabo-trimethoxyglutaric acid(XI), which is identical with that obtained 2* by oxidising Z-trimethyl6-arabonolactone (XII) and this in turn is obtained from the normaltrimethyl arabinose (XIII).IVH-OH -1Similarly also with cc-methylmannoside : this yields a tetra-methyl mannose (XIVj which passes to a crystalline tetramethyl8-mannonolactone (XV).Degradation of the latter leads to the2 6 W. N. Haworth, J. V. Loach, and C. W. Long, J., 1927, 3146.27 W. N. Haworth, E. L. Hirst, and D.I. Jones, ibid., p. 2428; A., 1173.28 W. N. Haworth and D. I. Jones, loc. cit.; 5. Fryde and R. W, Hum-phreye, J., 1927, 559; A,, 449ORGANIC CHEMISTRY .-PART I. 69isolation of d-arabo-trimethoxyglutaric acid (XVI,,29 which is theenantiomorph of (XI).p 2 HMeO*y*H 1 Me 0.F TO-1 -€I MeO-7-H--+ MeO-F*H Me0q.HMeg:v::Me I H-Q-OMe 1 H*Q=QMe? ! IH*‘i €I*F--J CO,HCH2-OMe CH,. ORfe(XIV.) (XV-) (XVI.)The authors conclude that t’he usual forms of methylgalacto-side and methylmannoside are normal forms in that they arestructurally similar to the normal methylglucosidea. Galactoseand one of the known varieties of mannose seem to possess, there-fore, the six-membered ring (amylene-oxide) structure. This canalso be said for the a- and p-methylarabinosides and methyl-xylosides , and similarly for ordinary arabinose and xylose.A like interest attaches to the determination of the structureof p-methylfructoaide through its characteristic derivative, crystal-line tetramethyl fructose (XVII).The conclusions reported lastyear30 have received extended verification in that this sugar isshown definitely to pass on oxidation with nitric acid to the amylene-oxide lactol-acid (XVIII) 31 and then, by degradation, t o d-arabo-trimethoxyglutaric acid (XIX), which is identical with (XVI).FH,*OMe , ---- QO2H d;-o-H(XVIII. CH2 )r--?*OH QO2H 1 Me0.y.H \ MeO-F*H Me 0 -y*HH*y*OMe ‘ H*r*OMe H-F-OMe L H*$?*OMe H*y*OMeCO,H(XIX.) Q g ; 2 M e (XVII. )It is thus seen that p-methylfructoside possesses the same typeof cyclic structure as a- and p-methylglucosides; and evidently thecrystalline fructose, in common with a- and p-glucose, is suitablyrepresented by the amylene-oxide formula.Turning now to the sugar derivatives related to y-methyl-glucoside (XX), it is found that the derived tetramethyl y-glucose(XXI) yields a crystalline tetramethyl y-gluconolactone (XXII) ,which passes by oxidative degradation 32 to d-dimethoxysuccinic20 E.H. Goodyear and W. N. Haworth, J., 1927, 3136.30 Ann. Reports, 1926, 23, 80.31 W. N. Haworth, E. L. Hirst, and A. Learner, J., 1927, 1040; A., 649.aa W. N. Haworth, 33. L. Hirst, and E. J. Miller, Zoc. cit70 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.acid (XXIII). Direct support is thus given to the butylene-oxidering €ormulz for these derivatives of y-glucose.Q01H*F---'MeO*Q*H QO2HMe 0 *Q *€€MeO-Q*H I --+ MeO*y*HCO,HI QH*OHH*Q-H*Q*OMe(XXIV.) (XXV.)CH2*OMe (XXVI.)Similarly, tetramethyl y-mannonolactone (XXV), which hasbeen ascertained to be structurally related to y-mannose-diacetone(XXIV), gives rise to a degradation product recognisable 33 asi-dimethoxysuccinic acid (XXVI). In no case is it observed that alactone from a y-sugar derivative yields on oxidation a trimethoxy-glutaric acid, and the above evidence permits of no suggestionthat an ethylene-oxide or propylene-oxide ring is present in thesey-sugars.Considerable importance is attached to the observations nowrecorded that d-trimethyl y-arabonolactone (XXIX) is intimatelyrelated t o and obtainable from tetramethyl y-fructose (XXVII).The latter sugar undergoes oxidation with nitric acid to give abutylene-oxidic 34 trimethyl lactol acid (XXVIII) which is degradedby acid permanganate t o crystalline d-trimethyl y -arabonol ac t one.The further oxidation of the latter confi~ms its previously deter-mined structure, since it has now been degraded 35 to Z-dimethoxy-succinic acid (XXX), and the crystalline methylamide of the latteris identical with that prepared from Z-tartaric acid.The enantio-morphic ,?-variety of trimethyl y-arabonolactone (XXXII), whichis derived from the y-form of trimethyl arabinose (XXXI), gave33 E. H. Goodyear and W. N. Haworth, loc. cit.34 J. Avery, W. N. Haworth, and E.L. Hirst, J . , 1927, 2308; A., 1057;W. N. Haworth, E. L. Hirst, and V. S. Nicholson, ibid., p. 1513; A., 859.s 6 W. N. Haworth, E. L. Hirst, and A. Learner, ibid., p. 2432 ; A., 1173ORGANIC CHEMISTRY .-PART I. 71on further oxidation the corresponding d-dimethoxysuccinic acid(XXXIII) , which was similarly identified.FH,*OMe _-__. 702H ----CH,*OMe CH,*OMe(XXVII. ) (XXVIII. ) (XXIX. ) (=x*)x-vo H*$J*OMe p 2 HMe0.Q.H + H*F*Ol\leMeO*(-i*HC0,H(XXXI.) (XXXII.) . (XXXIII.)--+L V * HCH,*OMe CH,*OMeThese experimental results appear to admit only of the interpret-ation that the y-lactones derived from methylated aldopentoseshad been correctly diagnosed and the butylene-oxide formulaapplied to tetramethyl y-fructose in the Report of last year isfinally confirmed.It is also clear that the butylene-oxide structureallocated to derivatives of y-arabinose is established, thus bringingall the known y-sugars within a comprehensive generalisation.Collateral evidence of the butylene-oxide character of tetra-methyl y-fructose (XXVII) is furnished by the unexpected observ-ations that this sugar passes with remarkable ease,36 in contactwith either dilute mineral acid or with acetic anhydride and sodiumacetate, into w-methoxymethylfurfural (XXXIV), which wasidentified through its oxime and semicarbazone as well as throughthe corresponding acid (XXXV). The latter was compared withauthentic crystalline o-methoxynzethylfurancarboxylic acid prc-pared from ordinary fructose and also from glucosamine by theFischer transformation of chitonic acid t o o-hydroxymethyl-f urfural.CH( OMe)*C(OH)*CH,*OMe CH:C=CHO CH :C*CO,HCH( OMe)*CH*CH,*OMe(XXVII .) (XXXIV.) (XXXV.)H :C*CH2*OMeA mechanism for these transformations is advanced in explanationof the probable consecutive changes leading to the furan com-pounds. In this connexion it is also of interest to notice thatw-hydroxymethylfufural is formed from pine lignin by steam.37I >oa6 W. N. Haworth, E. L. Hirst, and V. S. Nicholson, Zoc. cit.87 W. Fuchs, Ber., 1927, 60, 1131; A., 66072 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Two crystalline derivatives of y -glucose have now been isolatedas the cy.- and p-forms of pentabenzoyl y-glucose.38 Their specificrotations ([.ID + 58.6" and -52.6") differ widely from those of thecorresponding normal glucose derivatives ( + 107.6" ; + 23.7").The latter values correspond fairly closely to those of a- and p-ghcose (+110" ; +17*5") and from these comparisons it may besurmised that, were it possible to isolate the two y-forms of thefree sugar, the a-form would have a much lower positive rotationthan the normal or usual form of a-glucose, whereas the p-formof y-glucose would be strongly lzvorotatory.Again, the aboverotations of a- and @-glucose are comparable in their range withthe values of the normal a- and @-methylglucosides, and it wouldappear that the two stereoisomeric forms of y-methylglucosidemay be expected to possess specific rotations similar in range tothe above pentabenzoyl derivatives of y-glucose, the p-form ofy-methylglucoside having a much higher laevorotation than thenormal p-methylglucoside.Tetramethyl 7-glucose is given an equilibrium rotation of [.ID - 11" and it is reported39 that the m.p. of one form is slightlyabove 0". It has again been shown that this sugar is formed in aseries of stages from glucose-diacetone, to which is thereforeattributed the butylene-oxide structure of a y-sugar. A viewexpressed in last year's Report, that in the formation of glucose-diacetone from crystallinc glucose the amylene-oxide ring of thelatter undergoes displacement, is supported by the authors of thesame paper.The use of the expression " normal sugar " was admitted to theterminology of the sugar group for the reason that it served todistinguish those sugar derivatives related to the " normal " a- andp-methylglucoaides from the so-called " y-sugars," which wererelated to the less stable y-methylglucoside isolated by Fischer in1914.Derivatives of sugars other than glucose have also beenreferred to the same two normal structural types, represented byCC- and 8-methylglucosides on the one hand and by y-methylglucosideon the other.The a- and p-methylarabinosides are normal in the sense thatboth are structurally related to a- and p-methylglucosides, and inthe same category are also p-methylxyloside, p-methylgalactoside,a-methylmannoside, p-methylfructoside, and a-methylrhamnoside.Thus the common forms of methylhexosides and pentosides are'' normal " and possess the amylene-oxide structure.Future workwill doubtless reveal crystalline methylhexosides and pentosides38 H. H. Sclzlubech and W. Huntenberg, Ber., 1927, 60, 1487; A., 858.39 F. Micheel and K. Hess, Annalen., 1926, 450, 21; A,, 1927, 43ORGANIC CHEMISTRY .-PART I. 73which conform to the butylene-oxide type of y-methylglucoside,which is at present recognised only as a liquid mixture of fwostereochemical forms.Knowledge of the structure of sugars has reached a stage atwhich, it is suggested,k0 confusing terms such as normal, y-, h-,amylene-oxide, butylene-oxide, 1 : &oxide, 1 : 4-oxide might con-veniently be replaced by a reformed nomenclature having a definiterelation to the structure and configuration of the sugars.It is seenthat the parent form of " normal '' or amylene-oxide sugars isrepresented by pyran, and of the y- or butylene-oxide augars byfuran,CH*OH CH*CH,-OH\ // CH*OH(A)and thus the reduced and hydroxylated parent forms represent thesimplest sugars. For example, (A) is an expression of the simplestnormal pentose, and (B) is that of the simplest tetrose-a y-sugar.(A) and (B) may conveniently be named pyranose and furanose.The simplest y-pentose would be (C), wherein a side chain is attachedto (B). The configuration of each sugar may be represented by theprefix xylo-, arabo-, etc., so that the spatial distribution of thehydroxyl groups, as well as the ring structure, would be clearlydefined by a terminology : xylo-pyranose, arabo-pyranose , etc.,and xylo -furanose, ara bo -f uranose, etc.(D)Similarly the two types of hexoses (D) and (E) may be termed gluco-pyranose and gluco-furanose, and the variation of the prefix tomanno-, galacto-, etc., would define the structure and configurationof the remaining aldohexoses.40 E.H. Goodyear and W. N. Haworth. Eoc. cit.c 74 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.HO.CB,~SOH / /*\ \ FH2 HO*CH,*fOH /O\ gHcrr,oHH-OH CH-OH E(0H)- HOK“ C L * (G)(F)The expressions fructo-pyranose (F) and fructo-furanose (G)correctly define the two constitutional forms of fructose.It must, however, be kept in view that both aldoses and ketosesmay, and probably do, react also as the open-chain aldehyde andketo-forms, and that this transitional phase is present in sugarsolutions which are undergoing or have undergone mutarotation.In the condition of equilibrium it is by no means impossible tocontemplate that the pyranose, furanose, and open-chain types ofsugars may all be present; but in the case of glucose, which hasbeen most widely studied, there seems little doubt that the pyranosetype preponderates even in aqueous solution.This problem isengaging the attention of physical chemists, and a clear statementof the present position of this line of inquiry has been contributed.The account of this given by T. M. Lowry 41 serves also to sum-marise the most recent results obtained in the study of the mutarot-ation of glucose and its derivatives in various solutions, and referenceshould be made to this interesting paper.(H) (K) (L)The synthesis of the natural glucoside coniferin is reported.42This has been effected by condensing acatobromoglucose with thepotassium derivative of 4-hydroxy-3-methoxycinnamaldehyde, andhydrolysis of the acetyl residues in the product.The synthesis of indican43 has been accomplished by the inter-action of rncthyl 3-hydroxyindole-2-carboxylate with acetobromo-glucose in acetone solution containing potassium hydroxide.41 2.physikal, Chem., 1927, 130, 125.42 H. Pauly and K. Feuerstein, Ber., 1927, 60, 1031 ; A, 649.43 A. Robertson, J., 1937, 1037ORGANIC CHEMISTRY .-PART I. 76Hydrolysis of the acetyl groups yielded 3-hydroxyindole-2-carb-oxylic acid- p-glucoside. Heating with sodium acetate and aceticanhydride led to the elimination of the carboxyl group and also tothe formation of an acetylated product, which was identical withpenta-acetylindican.The latter was deacetylated with methyl-alcoholic ammonia and gave indican, identical with the naturalglucoside.Two glucosides of alizarin have also been synthesised,44 butneither of these is found to be identical with ruberythric acid.Some progress has been made in redetermining the constitutionof the acetone-sugars, since the earlier formuh are of doubtfulvalidity. It is demonstrated that galactose-diacetone 45 is to berepresented by (H) (since it is convertible into fucose-diacetone) ;and a- and P-fructose-diacetones 46 by (K) and (L).Disa;ccharides.-The synthesis of disaccharides by simple anddirect union of hexoses constitutes a new and facile method.47It is reported that maltose is obtained by heating equal weights ofa- and P-glucose at 160" in a vacuum.Similarly, lactose is said tobe formed by heating p-glucose and P-galactose for 30 minutes a t150"/15 mm. in presence of zinc chloride, and melibiose, accordingto the same authors, is formed with almost equal facility.Galactose-diacetone condenses with acetobromoglucose withthe formation of a substituted di~accharide.4~ The free biose wasisolated as a dextrorotatory 6-glucosido-galactose. A synthesis ofthe naturally occurring primeverose has been accomplished bycombining49 1 : 2 : 3 : 4-tetra-acetyl glucose and acetohromoxyloseand hydrolysing the hepta-acetate to the disaccharide.Theconstitution of this sugar is therefore found to be (I) and it isprobably formed in nature from gentiobiose.The structural formula (11) deduced by earlier authors for maltose 50has been investigated by the progressive degradation of the biosethrough its oxime to a glucose-arabinose, which forms an osazone,and finally to a glucose-erythrose (111), which is found to be incapableof forming an 0sazone.~1 It is argued that the biose linking in thelatter must engage the second hydroxyl group in the erythrosechain, which is the equivalent of the fourth hydroxyl group in the44 E. Glaser and 0. Kahler, Ber., 1927, 60, 1349; A., 752.4 5 K. Freudenberg and K. Raschig, ibid., p. 1633; A,, 858.46 H. Ohle, ibid., p.1165; A., 649.4 7 A. Pictet and 11. Vogel, Compt. rend., 1927, 184, 1512; 185, 332; A.,4 8 K. Freudenberg, A. Noe, and E. Knopf, Ber., 1927, 60, 238; A., 230.49 B. Helferich and H. Rauch, Annalen, 1927, 455, 168; A., 859.50 W. N. Haworth and S. Peat, J., 1926, 3094; A., 1927, 135.5 1 G. Zemplhn, Ber., 1927, 60, 1555; A., 859.752, 960; Helu. Chim. Acta, 1927, 10, 280; A., 45076 A"UU REPORTS ON THE PROGRESS OF CHEMISTRY.reducing glucose residue in the original maltose. The formula (11)receives support from these conclusions, and also from the observ-ations of other authors who have studied the rate of lactone form-ation from maltobionic acid.52 The results indicate that the bioselinking is a t position 4 in the gluconic acid residue and that a six-ringlactone is formed by union of the acid group with the hydroxyl atposition 5.I(I.) HO*Q*HH*Y*OH 1CH2*OHHQ--'CH,*O*xylose CH,*OH(111.1 CH,*OHCellobiose (IV) is shown by the following observations to bebuilt up on the same structural plan as maltose.Oxidation of thebiose to cellobionic acid (V), followed by esterification and methyl-ation, yielded methyl octamethylcellobionate (VI) and by hydrolyticcleavage there were isolated the crystalline 2 : 3 : 4 : 6-tetramethylglucose, and also 2 : 3 : 5 : 6-tetramethyl gluconic acid (VII), whichgave on heating the corresponding crystalline 2 : 3 : 5 : 6-tetra-methyl y-ghmnolactone (VIII). This was identical with a specimenpreviously isolated from ( a ) methyl octamethylmaltobionate andCH,*OH (IV-1 *CHZ*OH CHZ*OH W.) *CH2*OHT02Me H- TO2H TO--1I (iH*OMe I QH*OH YH-YH2QH*OMe d?H*OMel QH-OMe yH*OMe 0TH-OMeJ yH*OMeo j YH-OMe --+ yH*OMeQHoOMe yH*OMeCH,-OMe CH,*OMe CH,*OMe CH,*OMe(;'H-OMe FH-WI.) (VII.) (VIII.)62 P. A. Lek-em and H. Sobotka, J . Biol. Chem., 1927, 71,471ORGANIC CHEMISTRY.-PART I. 77also from (b) 2 : 3 : 5 : 6-tetramethyl y-glucose, the structure ofwhich had already been determined by oxidation methods. Theconstitutional formula (IV) which had previously been determinedby other methods and by the sa,me authors 53 is thus confirmed.An analogous investigation was undertaken .to determine thestructure of lactose. Lactobionic acid gave on methylation methyloctamethyl-lactobionate, which on hydrolysis yielded crystalline2 : 3 : 4 : 6-tetramethyl galactose and 2 : 3 : 5 : 6-tetramethylgluconic acid (VII).The latter acid was transformed by heat intothe same crystalline lactone (VIII) as that which was isolated alsofrom (a) methyl octamethylmaltobionate, ( b ) methyl octamethyl-cellobionate, (c) 2 : 3 : 5 : 6-tetramethyl y-glucose. It follows thatlactobionic acid 54 has the same structural formula as cellobionicacid, modified, however, by having a galactose instead of a glucoseresidue a t the position marked * in the formula (V). The con-stitution allocated to lactose by previous authors is again confirmedby these data. The revision of the formula of glucose has servedadmirably the general plan for the formulation of the disaccharides ;and the determinations of constitution of lactose, cellobiose, gentio-biose, and melibiose during the pre-revision period fall naturallyinto the newer system of expression in which the constituent hexosesare shown as amylene-oxides or pyranoses.Maltose also conformsto this general plan.A disaccharide formula which has been affected by the revision ofthe older oxide-ring applied to the simple hexoses is that of sucrose.It is now shown that normal fructose is an amylene oxide or pyranose,and that the older butylene-oxidic formula assigned to this ketosemust now be allocated to the y-fructose, which is the componentoccurring in sucrose. It is thus established that the normal sugarswhich have been so far investigated are based on a common pyranosestructure, whether aldoses or ketoses, and y-fructose takes its place YH- VH,*OH[T€€*OH?-o-TFH*OH 7 4 (IX.) LYH-OH YHo0Y YH-CH,*OH YH CH,*OHalongside the y-aldoses as a butylene-oxide (or furanose) form, Theproofs leading to this conclusion are given in the section undermonosaccharide^,^^ but since the tetramethyl y-fructose isolatedfrom methylated sucrose has been utilised as the material on whichj3 W.N. Hamorth, C. W. Long, and J. H. G. Plant, J., 1927, 2809.54 W. N. Haworth and C. W. Long, ibid., p. 544; A,, 450.b5 See pp. 71, ‘7478 ANNUAL REPORTS ON TEE PROGRESS OF CHEMISTRY.the investigation is based, the structural formula of sucrose (IX)was naturally the main issue in these determinations, and thisformula, advanced last year, has received substantial confirmation.Whereas maltose, cellobiose and lactose are similarly constitutedin that (their essential stereochemical differences being neglected)they are all structurally represented by the formula (X),,/""\""\/' 1 ICH*OH /T 0CH*OH I CHCH,*OH I 1:::; :H*CH2\CH*OH \ /'QH 0 I CH CHCH*OH 0CH*OH CH*CH,*OHI I\ //\CH*OHI I6 1 ~ ~ 0 ~ CH*CH,-OH(XI.)the important bioses gentiobiose and melibiose conform to thestructural type (XI) wherein the non-reducing hexose component isattached t,o the reducing component through a hydroxyl linkedto the side chain of the latter, and not to a hydroxyl attached to thering as in (X).These formula for gentiobiose and melibiose were advanced someyears ago.The constitution of gentiobiose was verified last yearby synthesis, and this structure for melibiose is strongly supportedby two further papers.56 Methylated melibiose (XII) gave onhydrolytic cleavage the crystalline 2 : 3 : 4 : 6-tetramethyl galactose(XIII) and also 2 : 3 : 4-trimethyl glucose (XIV), recognised as itscrya talline glucosid e.QH*ORle ryH-rQH*OMe I YH*OMe1*QH*OMe J YH-OMe * 1 CH-OMe io FH*OMe I ---+ H*OMeCH,*OMe7H-JCH,--' CH2*OMe CH,*OH6e W. Charlton, W. N. Haworth, and W. J. Hickinbottom, J., 1927, 1527;(XII.) (XIV.) (XIII.)A., 859; W. N. Haworth, J. V. Loach, and C. W. Long, ibid., p. 3146ORGANIC CHEMISTRY .-PART I. 79The union of these two hydrolytic fragments could only haveexisted through the exposed hydroxyl in the terminal posittion in(XIV), from which it follows that methylated melibiose has thestructure (XII) and the free diaaccharide the corresponding formula,indicated also in another way in (XI).Again, melibiose gave onoxidation with bromine melibionic acid (XV) ; and this structuralformula alone could be applied to it, since the fully methylatedmelibionic ester (XVI) gave rise on hydrolytic cleavage to crystallinetetramethyl galactose (XIII) and to tetramethyl gluconic acid(XVII) which, on further oxidation, was transformed into thetetramethyl saccharic acid (XVIII).CH2-J CH,*OMe(XVI.) II IYH*OMe (XVII.)CHaOMe(XVIII.) QH*OMeCH*OMe$H*OMe $H*OMeCO,H CH,*OHThis structural formula for melibiose has been attacked byG.Zem~I&n,~7 who, by degrading the sugar through its oxime,failed to isolate either the galacto-arabjnose or its crystallinephenylosazone. The author attributes this failure to the presenceof the biose linking in the position shown below in the galacto-arabinose (XIX), since this would prevent osazone formation ;and the formula suggested by the same author for melibiose is (XX).[YH-O-’ YH&l r?H*OH ~~~~1 (xIx.) 0 YH*OH QH*OH b 0 (iH-0 QH*OH 0 (xx,) LYH~OH QH*OH I LTH-OH THOOH ITHOOH r Q H YH-OHCH2 FH---] TH QH--’CH,*OH CH2*OH CH,*OHAn alternative reason for the difficulty experienced by the authorin isolating the expected products may well be that on the basisof the melibiose formula (XI) which he attacks, the galacto-arabinoseb7 Ber., 1927, 60, 923; A,, 54580 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.obtained by degradation would be a butylene-oxide or y-sugar(XXI), and hitherto no crystalline osazone of this labile type hasbeen isolated.CH,*OHThe synthesis of a new disaccharide has been effected as follows :1 : 2 : 3 : 4-tetra-acetyl glucose was condensed with acetobromo-galactose in presence of silver oxide.The resulting octa-acetateof the glucose- p-galactoside (XXII) was not identical with melibioseocta-acetate, nor was the liberated disaccharide the same asmelibiose.A TH*OAc A TH*OAcFH*OAc QH*OAc 1V$X&*OAc 4- 1 QH-OAcryH-OAc rQHBrCH,*OH CH,*OAc CH,---’ CH,*OAcThese authors 58 rightly conclude that either the configurationof melibiose as a P-galactoside is incorrect or the Btructure pre-viously ascribed to this biose (XI) is untenable.The configur-ation given to melibiose in the literature is based on the observation s9that this sugar is hydrolysed slowly by emulsin. Other authors 6oare unable to accept the interpretation which has been given tothis evidence based on enzyme cleavage, and support the argumentthat melibiose, having the recognised structure (XI), cannot bea glucose-p-galactoside, since on this assumption its high rotationis in disagreement with Hudson’s rule and with other data. Onthe view that melibiose is a glucose-a-galactoside, correspondingwith maltose as glucose-a-glucoside, the newly observed facts canbe reconciled.The constitutional formula ascribed to turanose and reportedlast year has received experimental support from another worker,who outlines a, much more convincing proof of the character ofthe trimethyl y-fructose component isolated from methylated(XXII. )63 B.Helferich and H. Rauch, Ber., 1926, 59, 2655; A., 1927, 44.50 E. Fischer and E. F. Armstrong, Bey., 1902, 35, 3144.6o W. Charlton, W. N. Haworth, and W. J. Hickinbottom, loc. cit.; W. NHaworth, J. V. Loach, and C. W. Long, Zoc. citORGANIC CHEMISTRY .-PART I. 81melezi tose. The constitutiona1 formula for the trisaccharidemelezitose appears, therefore, to be established.Gl There are, how-ever, difficulties in interpreting the behaviour of enzymes towardsthis sugar, in that a preparation from Aspergillus niger, which actsslowly on sucrose, attacks melezitose rapidly, and one authorsuggests that the sucrose residue does not occur in melezitose.A new trisaccharide has been synthesised by condensing 1 : 2 : 3 : 4-tetra-acetyl glucose with acetobromocellobiose in presence of silveroxide.The trisaccharide 62 was isolated as a crystalline substanceand gave a crystalline omzone. It does not appear to be identicalwith a natural product.PoZysaccharides.-There seems little prospect of the cessation ofinterest in the allocation of new structural formulz to the chiefmembers of the group of polysaccharides. The volume of experi-mental work contributed on this subject grows apace, and if ageneralisation on them be expected of the Reporter, it must besaid that the more recent results have proved the futility o€ allattempts to express the formulation of cellulose or starch until ourknowledge of many underlying problems has outgrown its presentlimitations.Determinations of molecular weights of derivativesof the polyaaccharides lead in many cases to precarious reasoning,particularly when, as is too often the case, the products examinedare amorphous mixtures. The contest is proceeding betweenrival theories concerning the factors which are operative in thecomplex aggregations in polysaccharides.One view of the constitution of polysaccharides postulates theexistence of a comparatively simple structural unit 63 which retainsits definite entity while existing in a highly associated form. Underselected conditions there may be a lesser degree of associationoperative in certain solvents, which means that the solute undergoesdispersion.Presumably the linkages responsible for this associationare not those of ordinary valency. The only alternative seems tobe to regard these as being due to the operation of co-ordinateco-valencies on the model of N. V. Sidgwick's suggestions.64 Thisrenders the formula originally suggested by K. Hess a very attractiveone,e1 (Miss) G. C. Leitch, J . , 1927, 558; A,, 450; M. Bride1 and C. Aagaard,62 B. Helferich and W. Schafer, Aianalen, 1926, 450, 229 ; A., 1927, 135.63 M. Bergmann, Annalen, 1927, 452, 121; A., 341. Compare Ann.Cornpt. rmd., 1927, 185, 147; A., 859.Reports, 1924, 21, 91.Presidential Address to Section B, Brit. Assoc. Reports, 192782 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.It is difficult, however, to conceive of the persistence of theseco-ordinate links when the hydroxyl groups of cellulose have beenreplaced by methoxyl or acetoxyl groups, and if for no other reason,it would appear that this consideration renders the formula of Hessdifficult of acceptance.On another plan, the simple structural unit is held to polymeriseto a higher unit or to higher units of varying complexity by struc-tural change.65 The breakdown of these complexes is then a step-wise process ending with the simplest possible form, which canagain revert to the more complex state. In this connexion, theilluminating example of Z-trimethyl 6-arabonolactone may becited. This crystalline substance polymerises with extremereadiness to a polymeric crystalline form, which has ten times themolecular weight of the original lactone and reverts to the simplelactone on heating. There seems to be on the whole little differencein principle between this second view of a polymerised unit and thetraditional view which adopts the conception of hexose rings linkedby connecting oxygen atoms in a, chain of indefinite length by theoperation of ordinary valency. It does not seem to be an essentialconsideration that the unit which undergoes polymerisation shouldretain, on this second plan, its structure in the polymerised aggregate,nor does it necessarily follow that the process of depolymerisationto the simplest unit would always be attainable. A modificationof the older, traditional formula has been advanced and has beenbased on a study of the X-ray spectrograph of cellulose in ramiefibre. The linkings between the constituent hexose rings, accordingto this formula, engage in alternative pairs the 1 : 1 -hydroxyl groupsand the 4 : 4-hydroxyl groups.66 It is also suggested that lateralcontact with hydroxyl groups of adjoining chains establishes afurther type of union by the functioning of subsidiary valency forces(co-ordinate valencies) which are more readily dissipated orovercome. etc. etc.

ISSN:0365-6217    

DOI:10.1039/AR9272400061

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

ANALYTICAL CHEMISTRY.DURING the period under review many delicate tests for the elementsand radicals have been examined and described. It is satisfactoryto record progress in devising specific reactions which may beapplied to detect single elements or to group certain elementsanalytically. Two trustworthy tests for aluminium have comeunder notice. The use of dyes as indicators for the determinationof halogens has been extensively investigated ; the procedure con-sists in the adsorption of the dye on the silver halide, the slightestexcess of silver producing a distinctively coloured silver salt of thedye which is more soluble than the precipitated halide.I n general volumetric determinations the question of accuratestandard substances has been inquired into.A fair range of definitestandard materials is thus becoming available for various volumetricprocesses. Particular attention may be directed to the value of themethod of precipitation and determination of certain metals bymeans of 8-hydroxyquinoline (" oxine "). Five metals constitutea " hydroxyquinoline " group, since they may be precipitated fromtartrate solutions in which caustic soda is also present. Oneadvantage of this process of determining certain metals is that the" factor '' for calculation of the metal from the weight of precipitateis small, so that a comparatively large weight of precipitate isobtained from very small proportions of metal.The troublesome separation of aluminium from beryllium hasbeen advanced definitely by a " tannin " method of separation.A thorough investigation of the possible sources of error in organicanalysis has been carried out, showing the kind of error which maybe anticipated in normal working.At the same time one of thedifficulties in the ter Meulen process of determining nitrogen hasbeen dealt with. Some attention has likewise been directed to themore accurate determination of elements such as arsenic, phosphorus,and selenium in organic compounds.Potentiometric methods have been studied, more particularlywith reference to the determination of the end-points in titrations,and one simplified method has come under observation.Inorganic Analysis.&ualitatiue.-Further work on the qualitative detection of metalsin single drops of the solution to be tested has resulted in a rapidN.A. Tananiev, J . Rws. PhyR. Chem. BOG., 1926,58, 219; A., 1927, 223ANALYTICAL CHEMISTRY. 197scheme for the detection of metals which give colour reactions in thepresence of one another. A detailed method of qualitative analysisavoiding the use of hydrogen sulphide, thioacetic acid, and sulphideshas been presented.2 When salts of each of 32 elements are mixedwith cobalt, nickel, or chromium nitrates, and a strip of filter-paperis immersed in the mixed solution, then dried and burnt, distinctivecolorations are obtained ; this method is preferred to the ordinaryblowpipe test on charcoal.3Photomicrographs of the characteristic double bromides ofcadmium with brucine and with quinine are given: and also of thecomplex copper zinc and cadmium zinc mercurithiocyanates.The formation of a blue coloration or precipitate with potassiumcobaltothiocyanate serves, in thc absence of copper and lead, as adelicate test for mercury; the presence of bismuth may cause theprecipitate to be violet in colour.Hot dilute solutions of bismuthnitrate or chloride give on addition of dimethylglyoxime andammonia an intense yellow coloration or precipitate ; arsenic,antimony, zinc, cobalt, manganese, and ferric salts interfere with thereaction. Bismuth salts in nitric acid solution give with potassiumcobalticyanide a characteristic crystalline precipitate which is notdarkened with 10 % potash solution (distinction from silver andmercurous cobalticyanides) but is darkened by alkaline stannitesolution (distinction from cadmium and zinc).g Addition of asolution of antimony pentachloride in hydrochloric acid to a dye ofthe xanthone group, e.g., tetraethylrhodamine, produces a violet toblue fluorescence or colour ; molybdenum, bismuth, thallic, gold,and mercuric salts and colloidal tungstic acid give similar reactions.The purple or pink coloration given with iron salts, in the absenceof oxidising agents, by thioglycollic acid followed by ammoniaprobably depends on the formation of a coloured ferrous thio-glycollic complex ion; sufficient reagent must be added to reduceany ferric iron present.1° The method may be applied quantit-atively and its delicacy is not affected by the presence of most othersalts.When disodium hydrogen phosphate is added graduallywith intermittent shaking to a neutral ferrous solution floating on a0. Macchia, Notiz. chim.-ind., 1927, 2, 191; A., 1045; 2. anal. Chern.,D. Migliacci and C. Crapetta, Ann. Chim. Appl., 1927, 17, 66; A., 329.A. Martini, Anal. Asoc. Quim. Argentina, 1927, 15, 52; A., 953.R. Montequi, Anal. Pis. Quim., 1927, 25, 82; A., 436.B. Ormont, 2. anal. Chem., 1927, 70, 308; A., 325; 2. anorg. Chem.,1927, 72, 201.1927, 181, 337; A,, 531. ' H. Kubina and J. Plichta, 2. anal. Chem., 1927, 72, 11; A., 1048. * A. Benedetti-Pichler, ibid., 1927, 70, 257; A., 331.@ E. Eegriwe, ibid., p. 400; A., 437.lo E. Lyons, J . Amer. Chem. Xoc., 1927, 49, 1916; A,, 953198 ANNUAL REPORTS ON THE PEOGRESS OB CHEMISTRY.chloroform solution of oximinoacetophenone, a blue colorationdevelops in the chloroform layer ; l1 cobalt, nickel, manganese,copper, zinc, cadmium, lead, and mercury impart colorations to thechloroform ranging from yellow to brown.1 : 2 : 5 : &Tetra-hydroxyanthraquinone gives with aluminium compounds in faintlyacid solution an intense violet coloration which may be utilised forthe determination of small quantities of the metal ; 12 tin, antimony,and bismuth are rendered inactive by addition of sodium tartrate,but copper and iron must be removed. The formation of a pinklake with alizarin serves as a confbmatory test for a1~minium.l~The best method for the micro-detection of zinc by precipitationas cobalticyanide followed by conversion into Rinman’s green hasbeen described, but a preliminary separation from other metals ofthe ammonium sulphide group is generally necessary.8 Thepresence of zinc is indicated by a turbidity when diphenylamine ordiphenylbenzidine acetate is added to the solution (acidified withacetic acid) followed by potassium ferricyanide ; l4 small amountsof chromate do not influence the test.When added to a stronglyammoniacal cobalt solution, sodium hyposulphite produces ayellow, orange, ruby-red, or dark red coloration, or a brownish-black precipitate, according to the concentration of the c0ba1t.l~Magnesium may be detected by the red coloration developed inalkaline solution by addition of titan-yellow ; l6 calcium and bariumincrease the intensity of the colour, whilst aluminium, tin, andbismuth interfere.The reaction has been applied t o the colorimetricdetermination of traces of magnesium,l7 and also to the detectionof magnesium in plant tissue.18 Zinc uranyl acetate gives withneutral but not too dilute solutions containing sodium a yellowcrystalline precipitate of a triple acetate.lg For the microchemicaldetection of beryllium the formation of uranyl sodium berylliumacetate (analogous to the zinc salt just mentioned) and of berylliumacetylacetonate are recommended.20 The formation of molybdenumthiocyanate is utilised for the qualitative detection of this metal.21l1 F. Krohnke, Ber., 1927, 60, [BJ, 627; A., 332.l2 I. M. Kolthoff, Chem. WeekbZad, 1927, 24, 447; A., 1047.Is W.J. Allardyce, J. Amer. Chern. SOC., 1927, 49, 1991; A., 963.l4 W. H. Cone and L. C. Cady, ibid., p. 2214; A,, 1046.15 P. Falciola, Qiorn. Chim. Ind. AppZ., 1926, 8, 612; A., 1927, 333.l6 I. M. Kolthoff, Chern. WeekbZad, 1927, 24, 264; A., 639.l7 Idena, Biochem. Z . , 1927, 185, 344; A,, 847.la H. Eilers, Chem. WeekbZad, 1927, 24, 448; A., 1046.l9 I. M. Kolthoff, Z. and. Chem., 1927, 70, 397; A., 436.2o V. Caglioti, Rend. Accnd. Sci. fis. mat. Napoli, 1927, [GJ, 33, 177; A.,*l F. C. Krauskopf and C. E. Swartz, J. Arner. Chem. Soc., 1926, 48, 3021;1046.A., 1927, 127AXALYTICAL CHEMISTRY. 199The presence of traces of the platinum metals in silver beadsobtained by cupellation causes peculiarities in the surface crystall-isation which permit of the identification of the foreignThe reaction between aurintricarboxylic acid (" aluminon ") andthe hydroxides of scandium, gallium, indium, thallium, and germ-anium has been in~estigated.~~The coloration given with safranine-T in the presence of mineralacid serves to detect one part of nitrite in 5,000,000 parts of water ;nitrates are detected after reduction to nitrite with magnesium anddilute sulphuric acid.24 Examination of the reaction of a largenumber of dyes with nitrous acid followed by a coupling agent showsthat magenta is the most sensitive, especially when used in con-junction with an a-derivative such as a-naphthol, a-naphthylamine,or H-acid rather than p-na~hthol.~~ A dichroic solution resultswhen a nitrate, even in small quantities, is mixed with sodiumnitrite and added to a solution of o-cresol in concentrated hydro-chloric acid.26 Nitrates, after removal of halides, give a redcoloration with a solution of diaminophenol in sulphuric acid ;some other oxidising agents which give the test, unlike nitrateshowever, afford a similar coloration with a solution of the reagentin hydrochloric acid.2'The sensitivity of the test for sulphites with fast-blue R is about1 in 175,000 ; 24 thiosulphates and thionates do not give the reaction,and sulphides and hydroxides interfere.The sensitiveness of somereagents and test papers for gaseous hydrogen sdphide28 andgaseous phosphine 29 has been examined. Reaction with nitro-prusside solution in the presence of hydrogen sulphide serves todistinguish between normal, mono-, and di-hydrogen salts oforthophosphoric acid .30 Minute traces of selenium in hydrochloricacid give with thiocarbamide a red colour ; with larger quantities,the element separates out q~antitatively.~~Methods for the identification of iodides and bromides, alone ortogether, have been examined,32 and also the micro-reactions of22 C.0. Bannister, J . Roy. Micros. SOC., 1927, 47, 143; A., 746.23 R. B. Corey and H. W. Rogers, J . Amer. Chem. SOC., 1927, 49, 216; A,,24 E . Eegrime, Z. anal. Chem., 1926, 69, 382; A., 1927, 125.25 J. V. Dubsk$ and A. OM&, Rec. tmv. chim., 1927, 46, 296; A., 688.26 A. H. Ware, Analyst, 1927, 52, 332; A., 638.z7 D. Buznea and R. Ckrnatesco, Ann. sci. Univ. Jassy, 1927, 14, 302; A.,28 M.Wilmet, Compt. rend., 1927, 184, 287; A., 221.2e Idem, ibid., p. 1456; A,, 744.so L. Rossi, Anal. ASOC. Quim. Argentina, 1926, 14, 239; A., 1927, 126.32 J. von Mik6, Arch. Pbrm., 1927, 865, 446; A,, 744.218.534.P. Falciole, Ann. Chinz. Appl., 1927, 17, 357; A., 952200 ANNUAL REPORTS ON THE PROQRESS OF CHEMISTRY.chlorides, bromides, and iodides.33 A method for the oxidation ofcyanides, thiocyanates, sulphides, sulphifes, thiosulphates, ferro- andferri-cyanides by hydrogen peroxide prior to the detection ofchlorides is described.34The application of zirconium salts for the removal of phosphatesin qualitative analysis has been further examined.35Quantitative.-Considerable attention has been devoted duringthe year t o the subject of standard substances for volumetricsolutions.Improvements have been made in the method of usingpotassium permanganate as an acidimetric standard.36 Othercompounds investigated are borax,37 oxalic acid dihydrate andpotassium quadroxalate,38 yellow mercuric oxide,39 potassiumhydrogen tartrate,40 and potassium hydrogen carbonate.41 Mercury,which can be obtained readily in the pure state, forms a usefulstandard for thiocyanate solutions instead of silver.39 Iron suitablefor the standardisation of permanganate is prepared by the electro-lysis of a solution of pure ferrous chloride containing sodium chlorideand boric acid, but iron deposited from oxalate solutions invariablycontains carbon.42 For the preservation of thiosulphate solutions,the addition of borax, disodium hydrogen phosphate, or carbondisulphide is advised.43 Solutions of oxalic acid should be pre-served in the dark.44Some of the methoxytriphenylcarbinols have been examined withreference t o their use as one-colour indicator^.^^The addition of small quantities of starch, preferably alkaline,brings about the flocculation of many troublesome precipitatesencountered in analysis.46 A general study of the conditions forproducing coalescence of precipitates has also been made."'Anhydrous barium or mixed alkaline-eitrth perchlorates have beenexamined as dehydrating agents.4* Mixed ammonium sulphate33 E.M. Chamot and C. W. Mason, Mikrochem., 1927, 5, 85; A., 744.34 (Mlle.) E. Spirescu, BuZ.Soc. chim.Romtinia, 1926, 8, 116; A., 1927, 637.35 F. Oberhauser, Ber., 1927, 60, [B], 36; A,, 222.36 T. Heczko, 2. anal. Chem., 1927, 71, 332; A., 848.37 T. Milobedski and H. Kaminska, BUZZ. SOC. chirn., 1927, [iv], 41, 957;38 K. 0. Schmitt, 2. anal. Chem., 1927, 71, 273; A., 845.80 I. M. Kolthoff and L. H. van Berk, ibid., p. 339; A., 845.40 G. Favrel, Ann. China. anal., 1927, [ii], 9, 161; A., 743.4 1 K. 0. Schmitt, 2. anal. Chem., 1927, 70, 321; A., 433.42 L. Moser and W. Schoninger, ibid., p. 235; A,, 332.d3 1. Yoshida, J . Chem. SOC. Japan, 1927, 48, 26; A., 435.d4 S. Ishimaru, BUZZ. Chem. Xoc. Japan, 1927, 2, 134; A., 743.45 I. M. Kolthoff, J . Amer. Chem. Xoc., 1927, 49, 1218; A., 637.46 W . Clayton, Analy8t, 1927, 52, 7 6 ; A., 329.O7 )I.M. Trimble, J . Physicaz Chem., 1927, 31, 601; A., 436.Pa G. F. Smith, Ind. Eng. Chern., 1927, 19, 411; A., 438,A., 846BNALYTICAL CHEMISTRY. 201and halide may be used for converting some of the salts of a numberof metals into the sulphates.49 A number of examples of inducedprecipitation of sulphides is given. 5OThe application of 8-hydroxyquinohne (“ oxine ”) as an analyticalreagent has been examined in considerable detail. The salts of thetype C,H,N*OMI, which are readily formed with most commonmetals, are generally insoluble in dilute acetic acid and in ammoni-acal tartrate solution ; in caustic soda solution containing tartrateonly copper, zinc, cadmium, magnesium, and ferrous iron areprecipitated-these metals constitute the “ hydroxyquinolinegroup.” 51 The salts are crystalline, easily filtered and washed,and may be used conveniently for the determination of metals ; theprecipitates may be weighed directly or the hydroxyquinolineresidue determined volumetrically by means of standard bromide-bromate s0lution.~2 The complexes are fairly stable to heat, andmay be quantitatively decomposed by careful ignition in the presenceof anhydrous oxalic acid, the metal being then weighed as oxide.It is known that neutral salts of magnesium, zinc, aluminium, andcopper cannot be titrated directly with alkali hydroxides on accountof the formation of basic salts and of adsorption of alkali; theseerrors are completely eliminated by addition of “ oxine ” to precipit-ate the metals, the liberated acid being then neutralised withstandard alkali with phenol-red or naphtholphthalein as indicator.53Further references are made below in connexion with the individualmetals so far investigated. The use of this reagent permits of a greatsaving of time in many practical determinations, as, for example,that of magnesium in aluminium alloys.Silver may be separated from lead by treating the mixed oxalateswith a small excess of ammonia, whereby silver oxalate is dis-Under no modification of conditions could quantitativeconversion of lead to peroxide by persulphate in ammoniacal orsodium hydroxide solution be obtained.55 An investigation of thesolubility of lead sulphate in water and in solutions of electrolytes,with the view of ascertaining the most favourable conditions for thegravimetric determination of lead as sulphate, indicates that thefinal concentration of sulphuric acid should be about 0.3%.56‘13 L.Moser and W. Maxymowicz, Ber., 1927, 60, [B], 646; A,, 435.6O W. Btjttger and K. Druschke, Annalen, 1927, 453, 325; A., 536.51 R. Berg, J . pr. Chem., 1927, [ii], 115, 178; A., 674.62 Idem, Pham. Ztg., 1926, 71, 1542.F. L. Hahn and E. Hartleb, 2. anal. Chem., 1927, 71, 225; A,, 745.54 H. Brintzinger, ibid., 1927, 70, 448; A., 535.6 s P. Ekwall, ibid., p. 161; A., 223.56 M. Huybrechts and H. Ramelot, Bull. SOC. chirn. Bdg., 1927, 36, 239;A., 536.a 202 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Copper is precipitated by 8-hydroxyquinoline from dilute aceticacid or from sodium hydroxide-tartrate solution ; in this lattercase, ferric iron, bismuth, tin, arsenic, and antimony are not precipit-ated. The copper may be determined subsequently by the iodidemethod or, in the absence of other metals of the '' oxine " group,the complex may be weighed directly.57 Copper, after reductionto the cuprous condition, is separated from mercury as thiocyanate ;excess of reagent in the filtrate is oxidised with bromine beforeprecipitation of the mercury as ~ulphide.5~ Cupric salts are reducedby shaking with bismuth amalgam in warm hydrochloric acidsolution ; the cuprous chloride is then titrated with dichromate,diphenylamine being used as internal indicator.59 Stannic salts aresimilarly reduced.For the rapid determination of copper, a processwhereby copper pyridine thiocyanate may be weighed directly hasbeen worked out.60The precipitation of bismuth with pyrogallol has been appliedto the micro-determination of this metal,61 and a number of volu-metric methods has aIso been investigated.62 Bismuth can beseparated from metals other than mercury, silver, lead, and thalliumby addition of 8- hydroxyquinoline in slightly acid solution, followedby potassium iodide; G3 the precipitated salt (C,H,ON),HBiI, istitrated with potassium iodate solution.In the absence of halides,bismuth is precipitated in the usual way from acetic or ammoniacaltartrate solution by '' oxine." 64Cadmium is precipitated from very dilute acetic acid or alkaline-tartrate solution by 8-hydroxyquinoline as the dihydrate.Driedat loo", the precipitate consists of Cd(c9H60N)2,1&H20, whichbecomes anhydrous a t 130". The cadmium compound is readilysoluble in hot 10% acetic acid, the corresponding copper salt beingprecipitated under these conditions.* The use of p-naphtha-quinoline and potassium iodide allows the precipitation of cadmiumfrom dilute sulphuric acid solution as the salt (C,,HgN)2H2Cd14 inpresence of zinc, cobalt, nickel, manganese, ferrous iron, chromium,aluminium, and magnesium ; 63 if tin and antimony are present, largeproportions of sodium tartrate or ammonium oxalate are necessary.R. Berg, 2. and. Chem., 1927, 70, 341; A., 436.68 J. Krauss, 2. angew. Chem., 1927, 40, 354; A,, 436.6* K. Someya, 2. anorg.Chem., 1927,160,404; A., 332; Sci. Rep. TdhorEu8o G. Spacu and J. Dick, 2. anal. Chem., 1927, 71, 185; A., 746.Imp. Univ., 1927, 16, 515; A., 848.R. Strebinger and E. Flaschner, Mikrochem., 1927, 5, 12; A., 334.W. Strecker and A. Herrmann, 2. anal. Chem., 1927, 72, 6 ; A., 1048.R. Berg and 0. Wurm, Ber., 1927, 60, [B], 1664; A,, 847.R. Berg, 2. anal. Chem., 1927, 72, 177.640 Idem, ibid., 1927, 71, 321; A., 847ANALYTICAL CHEMISTRY. 203Tin can be quantitatively separated from quinquevalent anti-mony, arsenic, lead, zinc, and certain other metals by precipitationwith ‘‘ cupferron.” 65 Stannous chloride can be satisfactorilytitrated with ferric chloride at the ordinary temperature if thesolution contains a t least half its volume of concentrated hydro-chloric acid, indigo-carmine being used as internal indicator.66In the iodometric determination of the antimonic ion, addition of alarge excess of potassium iodide and about 15% of hydrochloric acidinhibits the reverse reaction and gives good results rapidly.67Antimony can be separated from the alkali metals as, for example,in antimonates, by heating in a current of hydrogen chloride.Someobservations on the bromafe titration of antimony are descrj bed.6sFor the reduction of chromic chloride, shaking with zinc amalgamin an atmosphere of carbon dioxide is recommended; the resultingchromous chloride is then titrated with permanganate, dichromate,or ferric chloride.69 It is claimed that the use of “ infusible whiteprecipitate ” for the precipitation of chromium prior to gravimetricdetermination as oxide gives more accurate results than the usualmethod using ammonia; 70 the application of this reagent t o thedetermination of iron, aluminium, and chromium is also dealt withel~ewhere.~~ The colorimetric determination of iron by means ofsalicylic acid can be used in the presence of metals of the fmt threegroups, of sulphate, nitrate, acetate, moderate amounts of phosphate,and small quantities of organic matter; free alkali or organicpolybasic acids destroy the colour.72 Some observations on Knop’smethod of titrating iron are to be found in a paper on the determin-ation of ferrous iron in silicates.73 A procedure for the directdetermination of small quantities of iron as the bis-p-chlorophenyl-phosphate has been de~cribed.’~A procedure for the separation of aluminium from iron, copper,and magnesium by means of “ cupferron ” has been de~cribed,’~tt5 A.Pinkus and (Mlle.) J. Claessens, Bull. SOC. chim. Belg., 1927, 36, 413;A,, 848.66 W. Schluttig, 2. anal. Chern., 1927, 70, 56; A,, 223.6 7 A. Travers and Jouot, Compt. rend., 1927,184, 605; A., 334.6 8 G. Jander and W. Briill, Annalen, 1927,453, 332; A., 640.K. Someya, 2. anorg. Chem., 1927,160, 355; A., 333; rSci. Rep. TdhokuImp. Univ., 1927, 16, 397.7 0 IT7. Pumm, C’ollegium, 1927, 202; B.,’ 480.5 1 M. KranjEovi6 and G. Rukoni6, Arhiu Hemiju, 1927, 1, 18; A,, 746.A. Sagaidatchni and M. Ravitch, J. Russ. Phy8. Chem. SOC., 1926, 58,1018; A., 437.73 L.A. Smver, J. Amer. Chem. SOC., 1927, 49, 1472; B., 667.74 F. Zetzsche and M. Nachmann, Helv. Chim. Acta, 1926, 9,979; A,, 1927,75 A. Pinkus and E. Belche, Bull. SOC. chim. Bdg., 1927, 36, 277; A., 639.127. Compare idem, ibid., p. 420; A,, 1926, 705204 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.and also for the colorimetric determination of traces of aluminiumby observation of the colloidal solutions which this reagent giveswith small quantities ; the solution appears yellow by transmittedand blue by reflected light.76 Aluminium is precipitated by8-hydroxyquinoline from dilute acetic acid and from ammoniacaltartrate solution, but not from solutions containing alkali hydr-oxides ; the crystalline precipitate, Al(C,H,ON),, can be dried at110" for weighing, or may be dissolved in hydrochloric acid and thehydroxyquinoline determined bromometrically.77Cobalt can be rapidly determined by suitable treatment of theprecipitate given by pyridine and thiocyanate, whereby the com-pound is weighed as such ;78 a similar process is described in the caseof nickel.79 The magenta colour given by acid or neutral nickelsolutions with potassium dithio-oxalate is utilised for the colori-metric determination of nickel ; iron and cobalt must be removed.80Diphenylamine, or better diphenylbenzidine, may be used as aninternal indicator for the titration of zinc salts by ferrocyanide; asmall a'mount of ferricyanide must be present.81 Zinc is a memberof the " oxine " group of metals (vide supra), being precipitated by8-hydroxyquinoline from caustic alkaline tartrate solution as wellas from ammoniacal and acetic acid solution.82 In the separationof manganese from iron by precipitation as pyrophosphate, thepresence of considerable quantities of acetate, sulphate, potassium,or sodium ions causes high res~lts.~3 Quantitative oxidation ofbivalent manganese to permanganate is effected by nickel peroxide ;the process is carried out in two stages, but in the presence of ferric,chromium, and lead salts and more than 5 mg.of cobalt, somemodification is necessary.84Neutral barium solutions may be titrated with standard chromatesolution, with silver nitrate as internal indicator ; 85 a method hasbeen worked out for the micro-titration of barium with chromate(or vice versa) depending upon the appearance (or disappearance)of the yellow colour due to the chromate ion.86 A scheme for the7 6 M.L. de Brouckbre and E. Belche, Bull. SOC. chim. Eelg., 1927, 36,288;A., 640.77 F. L. Hahn and K. Vieweg, 2. anaE. Chem., 1927,71,122 ; A., 639; R. Berg,&d., p. 361 ; A., 848. ' 8 G. Spacu and J. Dick, ibid., p. 97; A., 640.V s Idem, ibid., p. 442; A., 1047.8o L. T. Fairhall, J. Ind. Hygiene, 1926, 8, 528; A., 1927, 127.W. H. Cone and L. C. Cady, J. Amer. Chem. SOC., 1927, 49, 356; A.,331; I. M. Kolthoff, Chem. Weekblad, 1927, 24, 203; A., 535.82 Hahn and Vieweg, loc. cit. ; R. Berg, 2. anal. Chem., 1927,71, 371 ; A., 745.*s D. BaIarev and N. Desev, ibid., 1927, 70, 444; A., 537.84 R. Lang, 2.anorg. Chem., 1926,158, 370; A., 1927, 126.8 5 R. F. Le Guyon, Bull. Soc. chim., 1927, [iv], 41, 99; A,, 223,B6 Idem, Compt. rend., 1927, 184, 945; A,, 537ANALYTICAL CHEMISTRY. 205quantitative separation of calcium, strontium, and barium has beendescribed; st potassium oxalate is preferred to the ammonium saltfor the precipitation of calcium or strontium, The conditions mostfavourable for the precipitation of pure calcium oxalate prior tothe volumetric determination by permanganate have been workedout.88 The ignition of calcium oxalate to oxide is greatly hastenedby heating in a current of oxygen; 89 this also applies to the con-version of magnesium ammonium phosphate to the pyrophosphate.Calcium can be directly determined in the presence of strontium andbarium by titration with standard ferrocyanide in a solution con-taining half its volume of alcohol, ammonium molybdate being usedas external indicator.90Magnesium is another member of the ‘‘ oxine ” group of metals(vide supra), being precipitated from alkaline-tartrate solutions by8-hydroxyquinoline ; it is not precipitated from acetic acid solutionsand is thus readily separated from the other metals of this group.g1Two studies have been made of the determination of magnesiumby the usual methods.92The reactions involved in the conversion of alkali chlorides intocarbonates by means of oxalic acid are not quantitafi~e.~~ Amethod is described for the determination of sodium as the tripleacetate with magnesium and uranium .94Improvements in the iodometric determination of vanadium aredescribed ; 95 volumetric methods are recorded based on the reduc-tion of vanadic acid to the vanadous state by liquid amalgams ofzinc or lead, followed by appropriate tit ration^.^^ Sexavalenttungsten is similarly determined after reduction to the quadrivalentstate with lead amalgam.Vanadium may be separated fromtungsten by precipitation with “ cupferron ” in the presence offluoride; 97 but if the amount of vanadium is small, a large amountof ammonium chloride should be present to assist the s e p a r a t i ~ n . ~ ~87 L. Szebellddy, 2. anal. Chem., 1927, 70, 39; A., 223.8 8 F. L. Hahn and G. Weiler, ibid., p. 1; A., 222.R. Cernatesco and (Mlle.) E. Viscautan, Ann. sci. Univ.Jussy, 1927,T. Gaspar y Arnal, Dim., Madrid, 1923; A,, 1927, 846.Hahn and Vieweg, loc. c i t . ; R. Berg, 2. anal. Chem., 1927,71, 23; A., 639.92 A. Tereschenko and M. Necritche, ULrazhe Chem. J., 1926,2,163; A., 1927,8s L. N. Muravlev, 2. anal. Chem., 1927,rZ, 15; A,, 1046; 2. anorg. Chem.,s4 D. I . Perieteanu, But. SOC. chim. Romdnia, 1927, 9, 17; A., 1046.s6 J. B. Ramsey, J. Amer. Chem. SOC., 1927, 49, 1138; A., 640.14, 305; A., 535.535; F. L. Hahn, K. Vieweg, andH.Meyer, Ber., 1927,60, [BJ, 971; A., 535.1927, 165, 137; A., 953.K. Someya, 2. anorg. Chem., 1927,163, 206; A., 746; Sci. Rep. TdhokuImp. Univ., 1927, 16, 521; A., 848.97 S. G. Clarke, Analyst, 1927, 52, 466; B., 752.98 Idem, ibid., p. 527; A., 1048206 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Some observations have been made on methods, both volumetricand gravimetric, for the determination of cerium.99 Aluminium isquantitatively separated from beryllium by treating a hot solutionof the metals as sulphates with saturated ammonium acetatesolution containing 30% of pure tannin.1 The conditions for theprecipitation of titanium with “ cupferron” in the presence ofuranium have been examined,2 and also for the determination ofthallium as chromate, methods of separation from other metalsbeing described.3 Hafnium and zirconium have been separatedby repeated precipitation of the phosphates from sulphuric acidsol~tion,~ and also by fractional decomposition of the complexphosphatofluoro - haf nat es and -zirconat es .5A study of the precipitation of tungsten by tannin has been made,6and also of the separation of tungsten from tantalum and niobium,advantage being taken of the solubility of sodium tungstate insolutions of high sodium-ion concentration in which the tantalateand niobate are practically insoluble.7Improvements have been made in a method of analysis of mixturesof sulphide, sulphite, and thiosulphate,s and also of mixtures of tri-,tetra-, and penta-thi~nates.~ Methods involving elimination ofsulphides, sulphites, etc., by boiling with hydrochloric acid in aninert atmosphere tend to give high results for sulphate.It istherefore recommended that sulphides be removed by freshlyprecipitated zinc carbonate in the presence of glycerol, sulphitesfixed by addition of formaldehyde and acetic acid, and thiosulphatesby iodine, barium sulphate being then precipitated from cold aceticacid solution.lO Other investigations have also been made of thedetermination of the sulphate ion as barium sulphate,ll and thealkalimetric titration of precipitated benzidine sulphate has like-wise been examined.n pp’-Diaminodiphenylamine is used as anindicator for the back-titration with dichromate of the excess of99 R. Lessnig, 2. anal. Chem., 1927, 71, 161; A., 746; T. Lindeman andM. Hafstad, ibid., 70, 433; A., 536.1 L. Moser and M. Niesse, Monatsh., 1927, 48, 113; A., 846.2 A. Angeletti, Ann. Chim. Appl., 1927, 17, 6 3 ; A., 333.3 L. Moser and A. Brukl, Monateh., 1926, 47, 709; A., 1927, 436.4 J.H. de Boer, 2. anorg. Chem., 1927,165, 16; A., 954.6 J. EI. de Boer and P. Koets, ibid., p. 21 ; A., 964.* W. R. Schoeller and C. Jahn, Analyst, 1927,52, 604; A., 1047.7 Idem, ibid., p. 606; A., 1047; ibid., 1926, 51, 613; A., 1927, 32.8 A. Kurtenacker and R. Wollak, 2. anorg. Chem., 1927,161, 201; A,, 534.9 A. Kurtenacker and E. Goldbach, ibid., 1927,166, 177; A., 1045.10 A. Kurtenacker and R. Wollak, 2. anal. Chem., 1927,71, 37; A., 638.11 V. MarjanoviO, Ariliv Hemiju, 1927, 1, 5; A,, 744; F. G. Gormuth,Amev. J . Pharm., 1927, 99,271; A., 638.12 I;. W. Haase, 2. angew. Chern., 1927, 40, 696; A,, 638; M. Talenti,Qiorn. Chim. In&. Appl., 1926, 8, 611; A,, 1927, 330ANALYTICAL CHEMISTRY. 207barium chloride used in volumetric determination of sulphates.13For the determination of concentrated sulphurous acid solutions,a more powerful oxidising agent than iodine is recommended;hypocldorite is used, excess being titrated iodometrically.14 Thisreagent is similarly applied to the determination of cyanides and ofthiocyanate.15 A volumetric determination of selenium andtellurium in the same solution depends on the oxidation of thedioxides to trioxides by permanganate and of tellurium dioxide aloneto trioxide by dichromate.l6Errors in the ordinary gasometric method of determining nitratesand nitrites are compensated by carrying out a blank determinationunder identical conditions, using a quantity of pure potassium nitratecontaining about the same quantity of nitrogen as the sample, andmaking due allowance for the deficiency f0und.l' Attention iscalled to the fact that certain compounds, in particular caffeine andtheobromine, when digested with sulphuric acid containing potassiumand copper sulphates, yield appreciable quantities of methyIamine.18An iodometric method for the determination of azoimide has beendescribed.Although the precipitate obtained when phosphine reacts withmercuric chloride is of variable character, the quantity of hydrogenchloride formed bears a definite ratio to the volume of phosphineand therefore affords a method of determination.20 The reactionof elementary phosphorus with potassium iodate in acid solution,whereby iodine is liberated, forms the basis of a method for determin-ing the element.21 1 : 2 : 5 : 8-Tetrahydroxyanthraquinone maybe used as indicator in the titration of an ammoniacal solution ofphosphate with standard magnesium solution,22 whilst magnesiumis determined by precipitation with a standard phosphate solution,the excess of which is then determined as above.A study of thedetermination of phosphate by precipitation as magnesium ammon-ium phosphate has been made,23 and also of the precipitation ofphosphate with reference to hydrogen-ion c~ncentration.~~l3 H. Roth, 2. angew. Chem., 1926, 39, 1599; A., 1927, 125.l4 J. Bicskei, 8. anorg. Chem., 1927, 160, 64; A., 330.l5 Idem, ibid., p. 271; A,, 331.l6 Z. Littman, Chem. Ztg., 1927, 51, 323; A., 534.I* B. Sjollema, and L. Seekles, Biochem. Z., 1927, 183, 240; A., 683.I9 J.Martin, J. Amer. Chem. SOC., 1927, 49, 2133; A,, 1046.2o M. Wilmet, Compt. rend., 1927, 185, 206; A,, 846.21 T. F. Buehrer and 0. E. Schupp, jun., J. Amer. Chem. Soc., 1927, 49,A. Pinkus and J. Jacobi, Bull. SOC. chim. Belg., 1927, 36, 448; A., 952.9; A., 222.F. L. Hahn and H. Meyer, Ber., 1927,60, [BJ, 976; A., 634.W. M. McNabb, J. Amer. Chem. SOC., 1927, 49, 891; A., 436.24 H. T. S. Britton, J., 1927, 614208 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.In the iodometric titration of arsenate, considerable advantageaccrues by working in concentrated hydrochloric acid solutions ; 25ignition of magnesium ammonium arsenate to the pyroarsenateshould be carried out a t 500-600°.26 Arsenites are accuratelyand rapidly determined by distillation with methyl alcohol saturatedwith hydrogen chloride, the removal of the arsenic trichloride beingfavoured by the presence of powdered quartz or of potassiumbromide .27Bromide and iodide ions may be removed, prior to the determin-ation of chloride, by treating the acidified solution with bromic acidin presence of acetone.The bromine and iodine liberated form,with the acetone, derivatives from which the halogen is not precipit-ated by silver nitrate.28 A similar method is applied to thedetermination of iodide in presence of chloride and bromide (pro-vided that the quantity of the latter is not large), titration of theacidified solution containing acetone being carried out with standardiodate solution.29 A combination of the two processes permits ofthe determination of the three halides in admixture, the bromidebeing found by difference.A most interesting development in the determination of halidesis the application 3O of certain dyestuffs as indicators. These act byadsorption on the colloidal particles of the silver halide. As soonas excess of silver ion is present, a salt of the dye with silver is formed,which is different in colour from the adsorbed dyestuff, but whichmust be more soluble than the silver halide itself in order that asharp colour change may be given.31 It has not been possible toascertain directly the extent of the indicator effect, but it is not asgreat as that in Mohr’s titration using chromate.32 Fajans usedfluorescein for the titration of chlorides and dibromofluorescein oreosin for bromides and iodides; the method gives excellent resultsin neutral or acetic acid solutions, provided that no great quantityof a strong electrolyte is present.33 The determination of iodide inz 5 K.Bottger and W. Bottger, 2. anal. Chem., 1927, 70, 97; A,, 222.26 W. M. McNabb, J . Amer. Chem. Soc., 1927, 49, 1451; A., 745.27 L. A. Deshusses and J. Deshusses, Helv. Chim. Acta, 1927, 10, 517; A.,28 R. Berg, 2. anal. Chem., 1926, 69, 342; A., 1927, 35.29 Idem, ibid., p. 369; A., 1927, 124.30 K. Fajans and 0. Hsssel, 2. Elektmchem., 1923, 29, 495; A., 1924, ii,60; k. Fajans and H. Wolff, 2. anorg. Chem., 1924, 137, 221; A., 1924, ii,776.a1 R. H. Burschtein, 2. anorg. Chem., 1927, 164, 219; A., 847; J .Russ.Phys. Chem. SOC., 1927, 59, 521; A., 1159.W. Bottger and K. 0. Schmitt, 2. anorg. Chem., 1924, 137, 246; A.,1924, ii, 776.33 L. M. Kolthoff and L. H. van Berk, 2. anal. Chem., 1927,70,369; A., 434,744ANALYTICAL CHEMISTRY. 209the presence of chloride can be effected by the use of eosin as indic-ator, preferably in the presence of ammonium carbonate ; 34bromides interfere with the titration. Among other dyes investig-ated in connexion with this method are rnethyl-vi~let,~~ metanil-yellow and brom~phenol-blue.~~The process has been applied to the determination of otherradicals than the halides ; thus fluorescein or eosin may be used forthe titration of thiocyanate with silver,% and sodium alizarin-sulphonate for ferrocyanide with lead.31Organic Analysis.Qualitative.-Iodine, generated by reaction of hypochlorite withpotassium iodide gives with amines a yellow coloration but noprecipitate, and with amides a yellow, red, or grey precipitate; 37with ammonium salts a black precipitate of nitrogen iodide is formed.Several toluene-wsulphonamides are described, suitable for theidentification of amines.38 The colours developed when nitrousgases react with mercaptans in solution in organic solvents serve as atest for the thiol-gro~p.~~For the detection of methyl alcohol after oxidation to formalde-hyde, potassium guaiacolsulphonate is preferable to guaiacol, asthe former does not react with acetaldehyde but gives the form-aldehyde reaction equally readily.40 A survey of the variousmethods for the detection of methyl alcohol in the presence of ethylalcohol has been made.*lThe formation of a white precipitate (of pentabromoacetone)with bromine after a preliminary oxidation with permanganateserves to detect citric acid in the presence of other organic acids orof chlorides, unless these are in great excess ; 42 a microchemical testfor citric acid in the presence of tartaric, malic, succinic, lactic, andoxalic acids depends on the formation of iod~acetone.~~Summaries have been made of the reactions and optical properties34 I.M. Kolthoff, 2. anal. Chern., 1927,70,395; A., 435.35 J. Hodakow, Z . physikal. Chem., 1927,127, 43; A., 743.36 I. M. Kolthoff, 2. anal. Chem., 1927, 71, 235; A., 744.3’ J. A. Sanchez, Anal.Asoc. Quirn. Argentina, 1926,14,366; A., 1027, 552.38 C. S. Marvel and H. B. Gillespie, J . Arner. Chem. SOC., 1926, 48, 2943;39 H. Rheinboldt, Ber., 1927, 60, [B], 184; A., 227; H. Lecher and W.40 H. Matthes, Pharm. Ztg., 1926,71, 1508; A., 1927, 66; R. Bauer, ibid.,L. 0. Wright, Ind. Eng. Chem., 1927,19, 750; A,, 687.42 N. Schoorl, Phamn. Weekblad, 1926, 63, 1455; A., 1927, 166.d3 M. Wagenaar, Chem. WeekbZad, 1927, 24, 258; A., 647.A., 1927, 66.Siefken, ibid., 1926, 59, [B], 2594; A., 1927, 39.p. 1543; A., 1927, 66210 lLNNUBL BEPORTS ON THE PROGRESS OW UHEMISTBP.of codeine,a and of the delicacy of the reactions for caffeine, theo-bromine, strychnine, brucine, quinine, and morphine.45 Analkaline solution of uric acid or other purine derivative gives withp-aminophenol or metol in the presence of an oxidising agent suchas sodium persulphate, a yellow coloration which is not affected bythe presence of dextrose or of proteins.46The furfuraldehyde reaction is given by both ketonic and alde-hydic methylpent~ses.~' Chlorophyll in ethereal solution, whenilluminated by ultra-violet radiation from a quartz lamp, exhibitsa vivid red fluorescence, not given by carotin or by xanthophyl1.48Piperidine reacts more readily and clearly than other reagents withthe labile halogen atoms of aryl halogenonitro-compounds.49 Thedevelopment of the colour produced by the action of nitrous acid onphenol, best at p , 4-5, is greatly accelerated by the presence ofmercury saltsY6O whilst the blue colour due to indophenol formationby the action of 2 : 6-dibromobenzoquinonechloroimide on phenol,preferably at pH 9-10, serves to detect the latter in a concentrationof 1 in 20,000,000.61 The colour reactions obtained by the inter-action of a number of common phenols and aldehydes in the presenceof alcohol and sulphuric acid are tabulated.52The reddish coloration which develops when an equimolecularmixture of benzene- or other sulphonyl chloride with pyridine or itshomologues is treated with caustic potash solutions constitutes anexceedingly delicate reaction for these bases.The colours, whichare not given by other cyclic bases, are discharged by light and byoxidising agents in the ~ o l d . 5 ~The methyl and ethyl ethers of thymol in acid solution react withsodium nitrite to give nitrosothymol, whereas the ethyl ethers ofcarvacrol , o - cresol , and anis ole yield no ni tros o - derivatives .5Optical data for the benzyl-g-thiocarbamide salts of naphthalene-mono- and certain -di-sulphonic acids are given as an aid to theidentification of the acids by microscopical exarninati~n.~~44 M.Wagenaar, Pham. Weekblad, 1927, 64, 671; A., 785.4 5 A. Eeiduschka and N. I. Meisner, Arch. Pharm., 1927,265, 455; A., 785.4 6 E. Pittarelli, Arch. P a m . sperim. Sci. aff., 1927, 43, 142; A,, 979.4 7 E. Voto6ek and F. RAc, Chem. Listy, 1927,6, 231; A., 688.4 8 P. W. Danckworth and E. Pfau, Arch. Pharm., 1927,265, 560; A., 1101.49 R. J. W. Le FBvre and E. E. Turner, J . , 1927, 113.so H. D.Gibbs, J . Biol. Chem., 1927, 71, 445; A., 475.5 1 Idem, ibid., 1927, 72, 649; A., 688.52 L. Ekkert, Pharm. Zentr., 1927, 68, 663; A,, 984.63 E. Gebauer-Fiilneggand F. Riesenfeld, Monatsh., 1926,47, 185; A., 1927,139.G4 3' W. Klingstedt and E. Sundstrom, J . pr. Chem., 1927, [ii], 116, 307;A., 1066.65 R. M. Haam and G. L. Keenan, J . Phyeical Chem., 1927,31,1082; A., 86ANALYTICAL CHEMISTRY. 21 1&mntitcttive.-An investigation into the possible sources of errorin organic elementary analysis has shown that, although the absorp-tion of carbon dioxide by lead dioxide may generally be ignored,error may be produced thereby in some circumstances; 66 theseveral sources from which small amounts of carbon dioxide may beintroduced are indi~ated.~’ Rubber is capable of absorbing veryvolatile foreign organic substances ; cork absorbs moisture andcarbon dioxide ; and lubricants should be applied judiciously.58Various devices are adopted to decrease the time necessary todetermine the carbon in a number of organic substances by boilingwith acid permanganate , the resultant carbon dioxide beingmeasured ; 59 the same principle is applied for micro-quantitativework, oxidation being effected by a sulphuric acid solution of potass-ium dichromate and silver chromate containing sodium sulphate.60The combustion of a number of organic compounds by chromic acidmixture has been investigated.61 Certain modifications of Pregl’smicro-combustion method have also been made.62Nitrogen may be determined in organic substances, other thanazo- and diazo-compounds, by Devarda’s method after wet com-bustion with acid permanganate in the presence of platinum; forthe determination of halogens, the oxidation is carried out in thepresence of silver nitrate.63 A modification of the direct combustionmethod has been made for the determination of bromine in botharomatic and aliphatic compounds .64 An arrangement to obviatethe tendency of solid compounds to distil unchanged through thereduction tube in ter Meulen’s catalytic hydrogenation process forthe determination of nitrogen is described.65Selenium in organic compounds is determined after oxidationin a Pam bomb by sodium peroxide in the presence of a, little sucroseand potassium nitrate ; 66 cacodylic acid or triphenylphosphine aredecomposed by heating with sulphuric acid and potassium per-aulphate prior to the determination of arsenic or phosphorusrespectively .G8 J.Lindner, Ber., 1926, 59, [B], 2561; A., 1927, 66.5 7 Idem, ibid., p. 2806; A., 1927, 166.58 Idem, ibid., 1927, 60, [B], 124; A., 269.sg B. Lustig, Biochem. Z . , 1927, 184, 67; A,, 687.6o M. Nicloux, Compt. rend., 1927, 184, 890; A., 436.T. von Fellenberg, Biochem. Z., 1927, 188, 365; A., 1100.82 G. Kemmerer and L. T. Hallett, Ind. Eng. Chem., 1927,19, 173; A., 269.83 B. Lustig, Biochem. Z., 1927,185, 349; A., 891.O4 F. 1;. Smith, Philippine J . Sci., 1927, 32, 315; A., 551.a 5 F. L. Smith and A. P. West, ibid., 1926, 31, 265; A., 1927, 166.6 6 E. H. Shaw and E.E. Reid, J . Amer. Chem. SOC., 1927,49,2330; A,, 1101.6 7 R. Poggi and A. Polverini, Atti $2. Accccd. Lincei, 1926, [vi], 4, 316; A.,1927, 66212 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Acetylation with acetic anhydride and pyridine is applied to thevolumetric determination of hydroxyl groups in sugars and otherorganic compounds.6* A modification of the ordinary Zeiselprocess has been made to permit of the determination of themethoxyl groups being made in the presence of aldehydes.69 It isproposed to substitute thiosulphate solution containing cadmiumsulphate for red phosphorus in the micro-determination of methoxyl,and also to make a small correction to allow for the low results dueto incomplete reaction between the alkyl iodide and silver nifrate.?OThe carbonyl group in aldehydes and ketones is determined bytreatment with phenylhydrazine, the excess being ascertained bymeasuring the nitrogen evolved after oxidation with Fehling'ssol~tion.~l Secondary nitrosoamines may be determined bymeasuring the nitric oxide evolved on boiling with ferrous chlorideand hydrochloric acid ; reduction by mercury and concentratedsulphuric acid is seldom quantitative, often by reason of partialconversion into C-nitroso-compounds.72Methyl chloride is determined by conversion into the iodide bytreatment under pressure in absolute-alcoholic solution with sodiumiodide ; the iodide is then distilled, and precipitated as the compoundCH,I,AgNO, ; the silver iodide obtained by hydrolysis amountsto 94% of the the~retical.~~ Small1 quantities of ethyl iodide in airor in very dilute solution are determined by keeping in contact withstandard silver nitrate solution in concentrated nitric acid.74 Thepink colour obtained by heating solutions containing chloroformwith pyridine in the presence of sodium hydroxide has been appliedto the colorimetric evaluation of very dilute aqueous solutions ofchloroform .75isoPropyl alcohol may be readily determined in the presence ofacetone by quantitative oxidation to acetone by chromic acid,followed by back-titration of the excess.76 Modifications of theusual method for determining diacetyl and acetylmethylcarbinolas nickel dimethylglyoxime are described. 77 Formic acid may bedetermined bromometrically either directly or after reduction ofmercuric to mercurous chloride.7* A mercury method for the6 8 V.L. Peterson and E. S . West, J . Biol. Chem., 1927, 74, 379; A., 1100.K. Wiesler, 2. angew. Chem., 1927, 40, 975; A., 1101.7O A. Friedrich, 2. physiol. Chem., 1927, 163, 141 ; A., 475.71 G. W. Ellis, J., 1927, 848.72 K. Lehmstedt, Ber., 1927, 60, [BJ, 1910; A., 1062.73 K. Roka and 0. Fuchs, 2. anal. Chem., 1927, 71, 381; A., 984.74 I. Starr, jun., and C. J. Gamble, J . Biol. Chem., 1927, 71, 509; A,, 270.7 5 W. H. Cole, J . Biol. Chem., 1926, 71, 173; A., 1927, 270.'6 H. A. Cassar, Ind. Eng. Chem., 1927, 19, 1061; A., 1100.7 7 C. B. van Niel, Biochem. Z . , 1927, 187, 472; A., 1101.78 F. Oberhauser and W. Hensinger, 2. anorg. Chem., 1927,160,366; A,, 476ANALYTICAL CHEMISTRY.213determination of acetone has been de~cribed,'~ whilst dihydroxy-acetone may be determined in solution by comparison of the timerequired for incipient reduction of Fehling's solution under standardconditions with that required for solutions of known concen-tration.8O Hexamethylenetetramine is evaluated by precipitationwith picric acid and determining the excess of reagent.81Xylose and the d-ribose of purine nucleotides are quantitativelyconverted into furfuraldehyde by distillation with 20 yo hydrochloricacid for 3 hours ; under these conditions the pyrimidine nucleotidesyield only small amounts of furfural.82 Dextrose is readily oxidisedby iodine to gluconic acid at ordinary temperatures in a stronglyalkaline medium.83Allantoic acid is converted by acid hydrolysis to carbamide whichis then precipitated as xanthyl~arbamide.~~ +Morphine is com-pletely precipitated by silicotungstic acid from solutions a t p~ 7.8,morphine being precipitated on acidifying the filtrate.s5The use of freshly precipitated silver oxide in the presence ofsulphuric acid for the precipitation of bases is preferred to that ofsilver nitrate or sulphate.86 By adjustment of a solution containinghistidine and arginine, together with excess of a soluble silver salt,top= 7.0, the silver compound of histidine is completely precipitated ;treatment of the filtrate with barium hydroxide to pH 10-11 resultsin the precipitation of the silver compound of arginine.87 Arginineis completely converted into carbamide by arginase in a medium ofp~ 9-9.s8 Titration of an amino-acid in 80% alcoholic solution withsodium hydroxide to a blue colour with thymolphthalein gives anaccurate measure of the carboxyl groups; back-titration of theresulting solution with hydrochloric acid t o a red colour withmethyl-red determines the amount of amino-compounds.89Pure cystine is precipitated to the extent of 97% by phospho-tungstic acid.g0Addition of lithium sulphate, as well as sodium carbonate andcyanide, prevents the formation of turbidity during the colorimetric79 A.Ionesco-Matiu, Ann. aci. Univ. Jassy, 1927, 14, 363; A., 687.81 (Mrs.) C. Kollo and B. N. Angelescu, Bzcl. SOC. chim. Romdnia, 1926, 8,H. Schmalfuss, Ber., 1927, 60, [B], 1045; A., 687.17; A,, 1927, 786.W.S. Hoffman, J . Biol. Chem., 1927, 73, 15; A., 687.R. Fosse and (Mlle.) V. Bossuyt, Compt. rend., 1927, 185, 308; A,, 891.A. K. Balls, J . Biol. Chem., 1927, 71, 537, 543; A., 264.H. B. Vickery and C. S. Leavenworth, J. Biol. Chem., 1927,72,403 ; A., 546.A. Bonot and T. Cahn, Compt. rend., 1927, 184, 246; A., 269.R. Martens, Bull. SOC. Chirn. biol., 1927, 9, 454; A., 687.8a A. Voorhies and A. M. Alvarado, Ind. Eng. Chem., 1927,19,848; A., 891.86 A. Kresel, 2. physiol. Chem., 1926, 161, 147; A., 1927, 270.'O R. H. A. Plimmer and J. Lowndes, Biochem. J., 1927, 21, 247; A., 269214 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY,determination of tyrosine with Folin and Looney’s phenol reagent ;the depth of colour given by tyrosine and tryptophan is in inverseproportion to their molecular weights.g1 Tyrosine itself, however,is more conveniently determined by a modification of Millon’sreaction.91, 92 The conversion of Z-a-amino-p-3 : 4-dihydroxy-phenylpropionic acid into melanin without flocculation in verydilute solution serves for the colorimetric determination of theamino-acid ; the method can be applied in the presence of t y r ~ s i p e .~ ~Diketopiperazines may be determined with fair accuracy in thepresence of amino-acids and peptides by Siegfried’s carbamatereaction.94The amino-nitrogen in nitroaniline and nitroacetanilide is obtainedas ammonia by refluxing with sodium hydroxide solution.95 Phenyl-acetylene is determined by weighing the copper compound pre-cipitated from alcoholic solution by ammoniacal cuprous chloridoPhysical Methods.The variation in size of the absorption bands of neutral and ofnitric acid solutions of neodymium and of praseodymium alone and inadmixture has been applied to the quantitative analysis of mixturesof these two elements?’ The characteristic absorption bands ofthe nitrite and nitrate ions in the ultra-violet region serve for thedetection of these ions in admixture with other common anions;for the detection of the weaker nitrate band in the presence ofnitrites, the latter are first decomposed by carbamide.Determin-ation of the extinction coefficients for specified regions serves forthe quantitative measurement of these anions.98 Extinctioncoefficients have been determined for the copper salt of copro-porphyrin in sodium hydroxide and for haemin, hzemochromogen,and coproporphyrin in solution in pyridine.The pyridine must bespecially purified for quantitative work, though it need not beanhydrous.99 Tables are given for the spectrophotometric determin-ation of glycuronic acid and its menthol derivative.191 0. Folin and V. Ciocalteu, J. Biol. Chem., 1927, 73, 627; A., 892.93 D. Zuverkalov, 2. phyaiol. Chem., 1927, 163, 185; A., 688.93 H. Schmalfuss and H. Lindemann, Biochem. Z . , 1927, 184, 10; A., 688.g4 A. Blanchetihre, Bull. SOC. chim., 1927, [iv], 41, 101; A., 269; Siegfried,Z. physiol. Chem., 1905, 44, 85; A., 1905, ii, 33; Ber., 1906, 39, 401; A . ,1906, i, 144.95 N.Semiganovsky, 2. anal. Chern., 1927,72, 27; A,, 1062.96 F. Hein and A. Meyer, ibid., p. 30; A., 1100.97 E. Delauney, Compt. rend., 1927, 185, 354; A., 847.g8 J. Eisenbrand, Pharm. Ztg., 1927, 72, 672; A., 638.99 A. Treibs, Z. phyaiol. Chem., 1927, 168, 68; A,, 892.1 G. Scheff, Biochem. Z., 1927,183, 341; A., 551ANALYTICAL CHEMISTRY. 215The diminution in the intensity of the lines of the arc spectrumof an element as the concentration of that element diminishes isnot uniform for the different lines composing the spectrum ; bycomparison, however, with mixtures of known concentration, silicabeing used as the diluent, uranium,S vanadium,* and tungsten maybe determined in ores with fair accuracy. Among other applicationsof the method may be recorded the determination of lead, bismuth, orcadmium in tin, tin in lead, lead in bismuth,6 lead in gold and ingold-copper alloys,' impurities in aluminium.* Attention isdirected to the fact that quantitative spectral analysis is beset withpitfall^.^ A method of determining tantalum by means of theX-ray spectrum has been described.10 A general review of thissubject is available.11Electrochmical Methods.The water content of glycerol is ascertained by measuring theconductance of potassium chloride.12 Zinc may be estimated insolutions, not too acid, by determining the conductivity of thesolution while adding standard sodium hydr0~ide.l~ A conductivitymethod for the determination of carbon dioxide has been described.14Electrolytic .-Antimony may be deposited electrolytically in thepresence of tin at 60-70' from a solution containing only justsufficient hydrochloric acid to prevent turbidity, a cathode pdtentidof about 0-3 volt being used; subsequent deposition of tin begins atpotential 0.6 volt, the temperature being lowered to 25" and a littlehydroxylamine hydrochloride being added.15 Mercury can be usedas cathode in the determination of cobalt, nickel, and the more noblemetals.16 Zinc may be determined accurately by electrolytic meansC.PorIezza and A. Donati, Ann. Chim. Appl., 1926, 16, 619; A,, 1927,Idem, ibid.,p. 622; A,, 1927, 184.Idem, ibid., 1927,17, 3; A., 334.A. Donati, ibid., p. 14; A., 333.E. Schweitzer, 2. anorg. Chem., 1927,164, 127; 165, 364; A., 845, 1046.A.h i s , Ver. CTm. deut. Naturforsch. Aerzte, 1926,19, 1114; A., 1927, 329.R. Adan, Bull. SOC. chim. Belg., 1926, 35, 447; B., 1927, 143.H. Konen, Ver. Ges. deut. Naturforsch. Aerzte, 1926,19,1108; A., 1927,329.lo G. von Hevesy and J. Bohm, 2. anorg. Chem., 1927,164, 69; A., 849.l1 P. Giinther, Ver. CTes. deut. Naturforsch. Aemte, 1926, 19, 1118; A., 1927,N. Kameyama and T. Sernba, J . SOC. Chem. Ind. Japan, 1927, 30, 10;l3 G. Sander and 0. Pfundt, 2. angew. Chem., 1926,39,1667; A,, 1927,126.l4 L. E. Bayliss, Biochem. J., 1927, 21, 662; A., 746..l6 A. Schleicher and L. Toussaint, 2. anorg. Chem., 1927, 159, 319; A.,124.329.A,, 330.222.H. S . Lukens, Trans. Amer. Electrochem. SOC., 1927, 61, 133; A., 533216 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.in the presence of dilute sulphuric acid if an anode of lead peroxide,supported on platinum, and a cathode of amalgamated brass areused.1'Potentimetric.-It is suggested that the irregularities observedin the potentiometric curves obtained in the determination of lead,barium, and mercury with chromate, and of cerium, lead, and zincwith ferrocyanide are due to dissolution and ionisation of theprecipitate ; this may be overcome by the addition of ethyl alcohol.l*The limits of accuracy of the titration of acids with alkali hydroxidesusing the quinhydrone electrode have been investigated,lg and alsothe effect of gelatin on the titration curves of various acids.20Several new forms of electrodes have been describedY2l also anabsolute method for titration of strong acids and halides in whichno potentiometer, standard cell, or normal electrode is required.22Titrations are best carried out when the reagent is added in equaland preferably not excessively small amounts ; 23 the graphicalmethod of ascertaining the end-point affords more accurate resultsthan the differential when, as in the case of the titration of iodideswith permanganate, the reacting substances are not in equimolecularratio.24Conditions are described for the titration of antimonic and stannicchlorides successively with chromous chloride ; 25 this reducing agenthas alSo been applied to the determination of copper,26 ofand of molybdenum.28 Silver and lead together may be determinedby titrating first with sodium chloride, using a silver electrode, andthen with ferrocyanide, using platinum.29Ferrous solutions can be accurately determined by titration withbromate.30l7 R.Belasio and E. Mellana, Ann. Chim. Appl., 1927, 17, 336; A., 953.1* I. Athanasiu, But. SOC. Rorndna Stiinte, 1926, 29, 7; A., 1927, 126.19 A. J. Rabinowitsch and V. A. Kargin, 2. Elektrochem., 1927, 33, 11;2o E. Little, J . Amer. Phamn. ASSOC., 1927, 16, 414; A., 743.21 T. R. Ball, Ind. Eng. Chem., 1927, 19, 370; A., 434; J. W. Williamsand T. A. Whitenack, J . Physical Chem., 1927,31, 519; A,, 434; I. I. Shukov,Nature, 1927, 120, 14; A., 743; F. Emslander, Woch. Brau., 1927, 44, 268;A., 743.A., 221.22 B. Cavanagh, J., 1927, 2207.23 F. L. Hahn and M. Frommer, 2. physikal. Chem., 1927,127, 1 ; A., 743.24 F. L. Hahn and G. Weiler, 2. anal. Chem., 1926,69, 417; A., 1927, 124.26 H. Brintzinger and F. Rodis, 2. anorg. Chem., 1927,166, 53; A., 1047.26 E. Zintl and G. Rienacker, ibid., 1927, 161, 374; A,, 536.27 Idem, ibid., p. 385; A,, 536.28 H. Brintzinger and F. Oschatz, ibid., 1927, 165, 221 ; A,, 963.29 E. Miiller and H. Hentschel, 2. unul. Chem., 1927, 72, 1 ; A., 1046.30 I. M. Kolthoff and J. J. Vleeschhouwer, Rec. trm. claim., 1926, 45, 923;A., 1927, 127AXALYTICAL CHEMISTRY. 217Measurement in this way of the bivalent ion formed by reducedferric iron with stannous chloride serves to evaluate the latter.31Ferrocyanide, not exceeding N/100-concentration, may also betitrated with b r ~ m a t e . ~ ~ The reaction of iron and aluminium saltswith sodium hydroxide has been followed potentiometrically ; 32 inthe case of aluminium, other bases have also been studied.33The zinc-ferrocyanide titration has been studied 34 and appliedto the determination of potassium by measuring the excess ofcalcium ferrocyanide over that required to precipitate the potassiumfrom a solution containing 30% of alcoh01.3~ Other investigationsin this field include that of tungstic acid,36 of certain of the noblemetals with titanous chloride:' and of dichromate with ferro-cyanide.38J. J. Fox.B. A. ELLIS.31 K. Sandved, Analy8t, 1927, 52, 2; A., 127.32 P. Drossbach, 2. anorg. Chem., 1927,166, 225; A., 1047.33 F. 0. Anderegg and G. W. Daubenspeck, Proc. Indiuna Acnd. Sci., 1925,34 G. G. Reissaus, Z . anal. Chem., 1926, 69, 450; A,, 1927, 126.35 A. Rauch, 2. anorg. Chem., 1927,160, 77; A., 331.36 H. T. S. Britton, J . , 1927, 147.37 W. D. Treadwell and M. Ziircher, Helv. Chim. Acta, 1927, 10, 281 ; A.,38 K. Someya, 2. unorg. Chem., 1926,159, 158; A,, 1927, 224.35, 141; A., 1927, 640.334

ISSN:0365-6217    

DOI:10.1039/AR9272400196

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

BIOCHEMISTRY.As in the past three years, this Report is written in two sections :plant, and animal biochemistry. The arrangement of the subjectmatter of the section dealing with the biochemistry of plantsfollows closely that adopted in the Report for 1926. Attentionhas been confined mainly to the biochemical and physiologicalaspects of the subject; the chemistry of soils and matters chieflyof agricultural chemical interest are discussed by the Reporteron " Soils and Fertilisers " in the Reports on Applied Chemistry.This arrangement brings these two Reports more or less into linewith the apportionment of papers by the Bureau of ChemicalAbstracts as between A and B Abstracts. There remain, how-ever, certain agricultural problems concerned with the biochemistryof soils and with plant nutrition which seem to find their placenaturally in this Report.It has been possible to deal only with a limited number of divisionsof the subject and those selected for treatment fall naturally intotwo main sections, one concerned with chemical changes accom-panying the activities of the lower forms of plant life and the otherwith the biochemistry of the higher plants.Consideration of workon the chemistry of the humic matter of the soil has been omitted,since, although a number of papers have appeared, no great advancehas been made and the subject has been very fully discussed inrecent Reports.I n the period under review, the publication by E. C. C. Balyand his co-workers of the results of further work on the photo-synthesis of naturally occurring compounds is of special importance.The announcement of their discovery of the mechanism of photo-synthesis in witro would appear to be a great step towards theunderstanding of this fundamental reaction as it occurs in natureand may be expected to lead to further rapid advances.The early work of Maze on the function of elements, other thanthe primary elements, in plant nutrition, and recent investigationson the importance of mineral elements in animal nutrition havestimulated the output of work on the inorganic constituents ofplants and considerable progress with this subject has been made.In considering the work of the year, a general impression is feltthat an increasing amount of interest is being taken in the bio-chemistry of plants.Apart from its fundamental importance froBIOCHEMISTRY. 219the purely scientific point of view, the subject is of the greatesteconomic consequence and its field includes investigations of valueto many industries besides the primary industry of agriculture.Broadly speaking, the general aim of a century’s work on plantnutrition has been the increase of the yield per acre-the quantity-of our agricultural crops, and, while that aim still remains, thereis now coupled with it an increasing tendency to investigate themore difficult and elusive problems connected with quality. Inthis connexion, research in this country has received welcome aidfrom the Empire Marketing Board, and it is to be expected thatfurther problems of this nature will be put forward for solution as anoutcome of the recent Imperial Conference on Agricultural Research.The writer of the section on plant biochemistry gratefully acknow-ledges the collaboration of Mr.H. J. G. Hines, B.Sc.In regard to the section of this Report which deals with thebiochemistry of animals the plan adopted is the same as that ofthe plant section, that is to say, only a limited number of subjectshave been dealt with and these comprise fields of research in whichnoteworthy and co-ordinated advances have been effected. Themain subjects reviewed are therefore : (1) the vitamins, in whichtheme special attention is directed to the differentiation of t’hecomponents of the group of water-soluble B-vitamins, and tothe formation of vitamin-l) by irradiation processes; (2) thechemistry of the hexose phosphates and the r6le of these com-pounds and other organic phosphates in muscle; (3) the work ofMeyerhof and his school on the lactic acid-forming enzymes isolatedfrom mammalian muscle; (4) the developments of the past twoyears in the investigation of hEmoglobin and related compounds.The Reporter feels that it is necessary to adopt some such schemeof restrictions as that just outlined in order to present a reasonablyhomogeneous and readable account within the space a t his disposal.At the same time, it is realised that consideration of many importantpapers pdblished during the past year has been omitted. That isinevitable and in no sense is the omission to be interpreted as ajudgment of inferiority in comparison with results which have beenincluded in the matter of this Report.Again no attempt hasbeen made to deal with isolated results in new or limited fields.It may be possible to deal with the latter category in future Reportswhen the lines of advance become more clearly demarcated.Micro-organisms.Decomposition of Organic Matter.-In last year’s Report mentionwas made of the work of Waksman and Skinner,l who showedAnn. Reports, 1926, 23, 213220 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.that both bacteria and fungi are concerned in the breakdown ofcelluloses in the .soil. The investigations of S. Winogradsky andof A. Kalnjns in this connexion have confirmed and extended theearlier work of Hutchinson and Clayton.* Both these workershave isolated new forms of bacteria from the soil capable of decom-posing cellulose aerobically ; the organisms studied by Winogradskyformed products resembling soil humus in being colloidal andnitrogenous, resistant to further bacterial attack, and soluble indilute alkalis.A careful study of the conditions attaching to the decompositionof cellulosic material has been made by R.D. Rege in continuationof the work of Hutchinson and Richards.6 The latter held theview that any cellulosic material containing 30% of pentosans anda relatively small amount of woody fibre would be readily decom-posable by soil micro-organisms provided that a supply of availablenitrogen and mineral nutrients was suitably incorporated with it.This has been confirmed by Rege's work, and it is shown that byusing suitable analytical methods, the " decomposability " of anycellulosic material can be predicted.A study of the agentsresponsible for decomposition showed that three common speciesof soil fungi were particularly active in the decomposition of ricestraw. Under aerobic conditions, these fungi, in combination,proved much more active than the soil bacteria alone. The optimumtemperature for the growth of one of them, a species of Acrirnoniella,lies between 40" and 50" and the maximum a t about 60°, and, underthe conditions obtaining in manure heaps, it is probable that thegreater part of the decomposition is performed by fungi. In experi-ments with poplar wood, attempts were made to hasten decom-position by increasing the supply of energy material, carbohydratesbeing added to the wood for that purpose ; the structural materialremained, however, unattacked until the easily available materialoutside was exhausted. It will be seen that, in the main, theresults of this investigation fall into line with the evidencemaccumul-ated in favour of the "lignin" hypothesis of the origin of humicmatter in soil and with the views of Waksman referred to in theReports for 1925 and 1926.7 It has been shown by A.C. Thaysenand W. E. Bakes,* in a study of the early stages of decompositionof oat-straw by micro-organisms, that the pentosans of the rawAnn. Report for 1925-26, Roth. Exp. Sta., 1927, p.37.J . Agric. Sci., 1919, 9, 143; Ann. Reports, 1919, 16, 174.Ann. Appl. Biol., 1927, 14, 1.J . Ministry Agric., 1921, 28, 398.0 Cornpt. rend., 1926, 183, 691; 1927, 184, 493.7 Ann. RepoTts, 1925, 22, 208; 1926, 23, 211.* Biochem. J., 1927, 21, 895BIOCHEMISTRY. 221material are a t least partly responsible for the appearance of thecarbohydrate fraction of the humus.C. Barthel and W. Bengtsson consider that, although in generalthe rate of decomposition of cellulose in plant material is directlyproportional to the content of nitrogen, the slower decompositionof leguminous plants in the soil as compared with straw crops maybe due to the higher content of non-cellulosic nitrogen-free materialin the former. This may be of interest in connexion with theresults obtained a t the Woburn Experimental Farm in the per-manent experiments on green manuring, where mustard has givenmuch better results than vetches.Our knowledge of the chemical and biological processes occurringin swamped and water-logged soils has hitherto been confined toscattered and isolated observations.In irrigated soils, moreparticularly those used for paddy rice, a water-logged conditionis normal and it is not to bc expected that the biochemical changeswill be the same as those occurring in well-aerated soils. V.Subrahmanyan 10 has published the first portion of a systematicinvestigation of this question. In his first paper he deals withthe influence of water-logging, under laboratory conditions, on thenitrogen compounds present, on the reaction, on gas production,and on bacterial numbers.The only prominent change in thenitrogen compounds is an increase in the amount of ammoniacalnitrogen, which results in a slightly more alkaline reaction. Theabsence of any appreciable production of carbon dioxide, and thelack of any marked increase in bacterial numbers, under aerobicor anaerobic conditions, suggested that the ammonia productionwas due to enzyme action. This hypothesis is confirmed by thework recorded in the second paper, in which it is shown that pro-duction of ammonia is not hindered by antiseptics and that anaqueous glycerol extract of the toluene-treated soil contains anagent which is able to produce ammonia from simple proteinderivatives and from which an active preparation of a deaminaseof a protein-like character was isolated.It is concluded thatthis enzymatic deamination may play an important part in plantnutrition in water-logged soils. It is perhaps worthy of notethat the rice plant seems to thrive better when supplied withnitrogen in the form of ammonium salts than when fertilised withnitrates.J. Konig l1 bas studied the decomposition of farmyard manureand its utilisation by plants and arrives a t conclusions which areKgl. Landtbruks. Ahad. Handl. Tid., 1927, 66, 306.lo J . Agric. Sci., 1927, 17, 429, 449.l1 Mitt. deut. Landw.-Qes., 1926, 662, 571 ; B., 1927, 198222 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.in close agreement with those of Bach referred to in last year’sReport.12 S.A. Waksman and F. G. Tenney13 have begun adetailed investigation of the composition of natural organic materialsand their decomposition in the soil.In dealing with the organic matter of soils and manures, thepublication of several papers on the action of hydrogen peroxideon organic matter should be mentioned. Following the methodproposed by G. W. Robinson and Jones l4 for the determinatioiiof the degree of humification of soil organic matter, G. H. G. Jones 15has attempted to determine the degree of humification of samplesof farmyard manure by means of hydrogen peroxide and findsgood correlation between the figures obtained and the degree ofdecomposition of the manure as judged by its appearance andhistory.W. 0. Robinson,16 in America, has also described amethod for the determination of the organic matter of soils bydigestion with hydrogen peroxide, but holds that hydrogen peroxidecannot be used to differentiate between humified and non-humifiedmaterial and that, in the presence of soil, it does not determine anyclearly defined type of organic matter. He further states that themethod is not in any case applicable to soils high in calcium carbon-ate, manganese dioxide, or chromium sesquioxide; and in thisconnexion, the work of K. Scharrer l7 on the catalytic decompositionof hydrogen peroxide by soils is of interest. He found that thepower to decompose hydrogen peroxide was much greater in neutraland alkaline soils than in acid soils, and that the greater the amountof manganese, iron or calcium in the soil the greater was its activity.Loss on ignition of soils involved loss of catalytic power only in sofar as it reduced the content of carbonate iind thereby the alkalinityof the soil.The soil containing the lowest number of bacteria hadalso the lowest catalytic power, but there was no direct relationshipbetween bacterial numbers and activity.Production of Acids by Micro-fungi.-The nutrition of micro-fungi and the chemical changes due to their activities have attracteda considerable amount of attention during the past two years, and,in the main, interest has centred in the production of acids, inparticular citric and oxalic acids, from glucose and sucrose. Theformation of citric and oxalic acids from sugars by Aspergillus nigerhas been confirmed by W.S. Butkewitsch,18 who showed thatl2 Ann. Repork?, 1926, 23, 213.l3 Soil Sci., 1927, 24, 275, 317.J . Agric. Sci., 1925, 15, 26; B., 1925, 140.Ibid., 1927, 17, 104; B., 232.l6 J . Agric. Rea., 1927, 34, 339; B., 535.Biochem. Z., 1927, 189, 125; B., 918.l8 Ibid., 1.927, 182, 99; A., 382BIOCHEMISTRY. 223gluconic acid also was produced.19 If calcium carbonate waspresent in the cultures or if nitrogenous compounds were absent,gluconic acid was formed in larger amounts than citric or oxalicacid. Under the same conditions, the mould Mucor 8tdoniferproduced fumaric and oxalic acids only. Working on the ferment-ation of various carbohydrates by two separate strains of A .niger,H. AmelungM observed that one of the strains gave rise to citricand gluconic acids only, whereas the other formed oxalic acid inaddition. Citric acid was obtained from compounds with three,five or six carbon atoms in the chain, but no acid was formedfrom four or seven carbon-atom chains (erythritol, glucoheptose).Gluconic acid was found only in cultures containing dextrose,sucrose, or maltose. It is considered doubtful whether gluconicacid is an intermediate stage in the fermentation of dextrose bythese moulds.3’. Challenger and his associates 21 have made a systematic studyof the mechanism of the formation of citric and oxalic acids fromrjugars by A . niger, investigating the fermentation of the variousbreakdown products in turn.When the mould is grown withcitric acid as the sole source of carbon, the formation of malonicand glyoxylic acids can be detected; acetone is also formed, thisbeing the first recorded instance of its production by a mould. Itwas suggested in the first paper by these authors that acetone-dicarboxylic acid was an intermediate stage in the formation ofacetone and the actual occurrence of this compound was demonstratedlater when ammonium citrate was employed instead of free citricacid as the source of carbon. Glyoxylic acid was obtained bothfrom malonic acid and from calcium acetate, in the latter casecalcium oxalate and glycollic acid also being formed. Franzenand Schmitt 22 have suggested that saccharic acid is an inter-mediate in the formation of citric acid in the higher plants; andthat this view holds for its formation from glucose by A .niger isshown by the isolation of potassium hydrogen saccharate fromcultures with glucose as the only source of carbon. Fermentationof calcium gluconate solutions gives rise to calcium saccharate andsome citrate and, further, potassium citrate is formed in consider-able amount when the mould is grown on potassium hydrogensaccharate solution. The formation of saccharic acid from glucoseThe formation of gluconic acid by other species of moulds has beeninvestigated by T. Takahashi and T. As&, Proc. Imp. Acad. Tokyo, 1927, 3,86; A., 696; 0. E. May, H. T. Herrick, C. Thom, and M. B. Church, J. Biol.Chem., 1927, 75, 417.2o 2. physiol. Chern., 1927, 166, 161; A., 703.*l F.Challenger, V. Subramaniam, and T. K. Walker, J., 1927, 200, 3044.23 Ber., 1926, 68, 222224 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.by certain yeasts23 appears to be the only other case known inwhich this compound has been shown to be formed by micro-organisms. The demonstration of the importance of this acid inthe mycological production of citric acid, and of acetonedicarboxylicacid in the further conversion of citric acid into oxalic acid, is ofconsiderable biochemical significance. The results obtained bythese authors lead to the suggestion that the mechanism of theformation of citric and oxalic acids by A . niger is as follows :-QH,*OH QH,*OH QO,H QH,*CO,HCHO C0,H C0,H CH,*CO,H(1) [QH*OH], + [$X*OH], + [QH*OH], --+ Q(OH)*CO,HGlucose.Gluconic acid. Saccharic acid. Citric acid.CH,*CO ,HQH,*CO,H QH,*CO,H f Acetic acid-(2) Q(OH)*CO,H -+ QO < QO2HCH,*CO,H CH,*CO,H h 7H2 4 CH,CO,H + CO,Citric acid. Acetonedicarboxylic C02H Acetic acid.acid. Malonic acid.(3) CH,*CO,H -+ QH,*OH --+ QHO + QO,HC0,H C0,H C0,HAcetic acid. Glycollic acid. Glyoxylic Oxalic acid.acid.AmelungZ4 states that oxalic acid appears to be the universalproduct of incomplete oxidation of organic substances and maybe produced by the breakdown of carbohydrates, proteins, fats,alcohols, and organic acids. Acid formation is unquestionablythe result of processes taking place in the living cell and does notoccur with dried preparations or with the expressed juice of fungi.The maximum action is attained a t the optimum temperature forgrowth.The fact, noted above, that different strains of A . nigergave rise to different end products may prove to be of importancein the detection and classification of strains of the same species offungi, a problem with which mycologists are much concerned a tthe present time.L. K. Pearson and H. S. Raper 25 have shown that the fatty acidsformed by A . niger and by Rhixopus nigricans vary with the tem-perature at which the organisms are grown. D. Chouchak26 dis-cusses the interesting question of the competition between themicro-organisms of the soil and higher plants for mineral nutrients ;23 See Griiss, Jahrb. wiss. Bot., 1926, 66, 156, 171, 177.24 LOG. cit., ref. 20.2b Biochem.J . , 1927, 21, 875; A., 906.26 Compt. rend., 1927, 185, 82BIOCHEMISTRY. 225and the calcium requirements of algze and fungi are dealt withby L ~ e w . ~ ' B. M. Bristol-Roach 2* has studied the carbon nutritionof some algae isolated from soil and finds that all the species testedwere capable of growth in complete darkness, provided that a suit-able organic compound was present, but the requirements ofindividual species and their responses to different conditions werewidely different. The respiratory and fermentative activities ofa number of species of green algae are discussed in an interestingpBper by L. Genev~is.~~ It is concluded that the " intramolecular "respiration of algae is essentially similar to yeast fermentation.Some other papers on a number of points relating to thenutrition of different species of fungi are noted below.30Higher Plants.Photosynthesis.-A distinct advance in our knowledge of themechanism of the photosynthesis of naturally occurring compoundsis marked by the appearance of three papers by E.C. C. Baly andhis collaborator^.^^ As the result of earlier work a t Liverpo01,~~the opinion was expressed that photosynthesis of carbohydratesby the action of ultra-violet light on carbonic acid took place intwo stages, involving, first, conversion of the carbonic acid moleculeinto activated formaldehyde and oxygen which then lost energyand appeared in their ordinary state, and, secondly, reactivationof the formaldehyde by light and its polymerisation to form reducingsugars.It is now held that it was unnecessary to have postulatedtwo separate stages and that the activated formaldehyde producedfrom the carbonic acid can itself polymerise to reducing sugarswithout loss of energy and subsequent re-activation. Accordingto this view, the small amounts of formaldehyde detected whenultra-violet light acts on aqueous solutions of carbonic acid are notdue to its direct formation in the first stage, but to the secondaryphotochemical decomposition of the photosynthesised carbohydrates.The earlier results obtained were criticised by C. W. Porter and27 Biol. Zentralbl., 1927, 17, 481.28 Ann. Bot., 1927, 41, 509; A., 994.29 Biochem. Z . , 1927, 186, 461; A., 905.30 M. Chikano and T.Kitano, 2. physiol. Chem., 1927,164, 217; A., 696;A. Rippel and H. Bortels, Biochem. Z . , 1927,184, 237; A., 597; H. Tamiya,Acta Phytochim., 1927, 3, 51; A., 906; Coupin, Compt. rend., 1927, 184,1575; Bach, ibid., p. 1578; A. HBe, Bull. SOC. Chim. biol., 1927, 9, 802;R. Meyer, 2. Pflanz. Diing., 1926, A , 8, 121; A., 1927, 280.s1 E. C. C. Baly, J. B. Davies, M. R. Johnson, and H. Shanassy, Proc. Roy.SOC., 1927, A , 116, 197; E. C. C. Baly, W. E. Stephen, and N. R. Hood,ibid., p. 212; E. C. C. Baly and J. B. Davies, ibid., p. 219; A,, 1040, 1041.See also E. C. C . Baly, Ind. Eng. Chem., 1924, 16, 1016.32 See Ann. Reports, 1922, 19, 220; 1923, 20, 220; 1924, 21, 184.REP.-VOL. XXIV. 226 -NU& REPORTS ON THE PROQRESS OF CHEMISTRY.H. C. Ramsperger,s who, taking extreme precautions in regard tothe purity of their materials, reached the conclusion that in com-plete absence of all impurities no trace of formaldehyde was formed.This divergence of opinion now appears to be explained, since Balyand his associates have shown that the action of ultra-violet lighton carbonic acid is to establish a photostationary state represented6H2C0, t C6HI2O, + 60,,the amount of carbohydrate present in this equilibrium being verysmall. This being so, the presence of oxidisable impurities wouldcause the reaction to proceed from left to right with the formationof a definite amount of carbohydrate which would be photochemic-ally decomposed to formaldehyde.The existence of this photo-stationary state was established by exposing carbonic acid toultra-violet light in the presence of Feder’s solution ; 34 definitereduction then took place, showing the presence of substances ofaldehydic nature.I n complete absence of carbon dioxide therewas no reduction. Hexoses were introduced as a component ofthe equilibrium on account of the work of J. C. Irvine and G. V.Pran~is,~5 who examined a photosynthesised sugar syrup obtainedby exposure of formaldehyde to ultra-violet light and found thatglucose is produced to the extent of about one-third of the totalreducing compounds formed.Attempts were then made to shift the equilibrium to the carbo-hydrate side by addition of a reducing agent to remove the oxygen,but without success, except in one case when rods of pure Swedishiron were used. The results obtained in these experiments, con-sidered in connexion with the work of Zenghelis,36 led to the investig-ation of the effect upon photosynthesis of carbohydrates of theintroduction of a surface capable of adsorbing carbonic acid.Brieflystated, it was found that, whereas no measurable reaction takesplace when pure carbonic acid in aqueous solution, free from allsuspended matter, is exposed to light, a very definite action occurswhen a surface which can adsorb the carbonic acid is present in thesolution. Complex organic compounds, and not formaldehyde, arephotosynthetically produced. These compounds char readily withsulphuric acid, and, after hydrolysis with hydrochloric acid, reduceBenedict’s solution.If ammonium carbonate or barium or potassiumnitrite was added, complex organic nitrogen compounds wereformed. The following materials proved effective in providingby38 J . Amer. Chem. SOC., 1925, 47, 79; A., 1925, ii, b73.a4 Arch. Phcsrm., 1907, 245, 25.Ind. Eng. Chem., 1924, 16, 1019; Ann. Reports, 1924, 21, 186.56 Cornpt. rend., 1920, 171, 167BIOCHEMISTRY. 227a suitable surface : aluminium powder, barium sulphate, freshlyprecipitated aluminium hydroxide, and the basic carbonates ofaluminium, zinc, and magnesium. Rigid precautions were takenand exhaustive tests carried out to ensure the complete absence ofall organic matter in the carbon dioxide and other materials used.It was noted that aluminium hydroxide loses its efficacy in pro-moting photosynthesis after being in contact with water for somehours, and since the experimental details were identical whennegative results were obtained with this material (the only variablefactor being the nature of the surface), this offers further proof thatthe possibility of the positive results being due to the presence oforganic impurities is excluded.A further important step towards an explanation of photo-synthesis of carbohydrates under natural conditions was achievedas the results of experiments with coloured powders in visible light.When the basic carbonate of nickel or of cobalt was used to providea surface capable of adsorbing carbon dioxide, photosynthesisedcompounds similar to those described above were produced byexposure of the solutions to visible light only.Formaldehyde couldnot be detected, i.e., the activated formaldehyde formed does notescape from the reaction sphere and become ordinary formaldehydeby loss of energy. Great care was again taken to ensure absenceof impurities. The yield of organic material obtained was greaterthan when white powders and ultra-violet light were employed.One a t least of the products was a carbohydrate which reducedBenedict’s solution, gave the Molisch and Rubner reactions, andformed a solid osazone. There were also more complex substanceswhich on hydrolysis reduced Benedict’s solution. If ammoniumbicarbonate was added, complex nitrogen compounds were formed,as in ultra-violet light. Photosynthesis of carbohydrates has thusbeen carried out in the laboratory using an exciting wave-lengthcharacteristic of natural photosynthesis.The oxygen set free during the photosynthesis tends to poisonthe surface.Nickel or cobalt sesquioxide is formed as a film onthe basic carbonate, and when the surface is completely poisoned,the carbohydrates previously formed tend to be photochemicallydecomposed under strong illumination. The surface slowly recoversitself under water.In the third paper of the series, Baly and Davies discuss thequestion as to how far the photosynthesis achieved in vitro is similarto the process as it occurs in the living leaf. Whilst some of theirsuggested explanations of details are admittedly speculative, thereis a close resemblance in many points.Ordinary formaldehydedoes not take part in either case. I n the laboratory, the proces228 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.has been realised by the action of light on carbonic acid adsorbedon a surface, and there is a considerable amount of evidence to showthat a limiting surface exists in the chloroplasts of plants and isnecessary for normal photosynthesis. Visible light and a visiblycoloured surface are concerned in both processes. Fatigue effectsare observed when the living leaf is exposed to too long and intenseillumination, and when, in the laboratory, the surf ace becomespoisoned by oxygen.37 There is a slow recovery in both cases andit appears that the photosynthesis must not proceed a t a morerapid rate than this recovery process.The actual nature of thecarbohydrates synthesised in the $laboratory still remains to beascertained.Numerous attempts have been made by various investigatorsto isolate simple aldehydes from the leaves of plants, with a viewto showing their existence as intermediate products in the processof as~imilation.~~ It would seem probable from the work justdiscussed that such substances, if present in the leaf, are likely tobe decomposition products rather than intermediates.Some other recent work bearing on this subject may be con-sidered in connexion with these interesting results. D. Burk39reports attempts to induce photochemical reactions betweenammonia and various carbon compounds, including carbondioxide, formic acid, formaldehyde, and dextrose.The solutionswere contained in thin glass vessels and exposed to sunlight, variouscoloured catalysts being used. In some experiments, sunlight wascondensed through lenses. No complex nitrogen compounds wereproduced from ammonia and carbonaceous substances, and withvery few exceptions, no action of any sort was observed. It issignificant that the exceptional cases when action was observedwere those in which insoluble oxides were used as catalysts. Whenmercuric oxide was employed, formates, carbonates, nitrates, andnitrites were produced photochemically and the amounts formedseemed t o be related to the extent of surface rather than to the bulkof the mercuric oxide used. Ammonia also gave rise to nitrites andnitrates in the presence of zinc oxide, but not when solutions ofzinc salts were used.It is clear from the Liverpool work that theessential surface capable of adsorbing carbonic acid was lacking inmost of Burk’s experiments, and, further, that the excessive illumin-ation employed, by inducing secondary photochemical decomposi-37 The probable formation of a peroxide is referred to; and it is of interestthat H. Gaffron (Bet-., 1927,60, [BJ, 2229; A,, 1225) has recently shown thatacceptor peroxides are produced during the photo-oxidation of aliphaticamines in the presence of chlorophyll.38 See Ann. Reports, 1926, 23, 225.3@ J . Phy~vicd Chem., 1927, 31, 1338; A., 1040BIOCHEMISTRY. 229tion, would not be favourable to the detection of any complexproducts formed.A. K. Bhattacharya and N. R. Dharm havefound that finely divided zinc oxide acts as a sensitiser for manyphotochemical reactions, including the formation of carbohydratesfrom formaldehyde.K. Noack 41 has studied the condition of chlorophyll in the livingplant. Chlorophyll adsorbed from solution in light petroleum bymeans of dry colloidal aluminium hydroxide or dry lipin-free globinshows the red fluorescence characteristic of the chloroplasts ofplants, and it appears that the red fluorescence is dependent on theexistence of chlorophyll in the molecular disperse condition. Inthe living plant, chlorophyll is probably adsorbed on the proteinsof the chloroplasts. The work of H. Gaffron 42 on oxygen transportby chlorophyll is also of interest.When chlorophyll is dissolvedin acetone and exposed to light, it undergoes gradual oxidation,but if an oxygen acceptor is present, the chlorophyll is unchanged.It was shown that the ratio photochemical action/radiant energyadsorbed, as determined experimentally, was substantially thesame as the value obtained from Einstein’s law of photochemicalequivalence on the assumption that one quantum of energy wasused up for every molecule of oxygen utilised. This held true overa considerable range of wave-lengths, but was found to be dependenton the concentration of the oxygen acceptor.Carbohydrate Production and Transport.E. J. Maskel143 has made observations on starch production inthe potato, using a technique that made it possible to carry out thework in the field. By employing Sach’s iodine test and a Ridgwaycolour scale, the net starch production was estimated as the differ-ence between the colour value developed by a leaflet exposed tolight on the plant for three hours and the colour value of theopposite leaflet which had remained covered.The observationswere made on plants growing on plots which had received respect-ively potassium chloride, potassium sulphate, low-grade potashsalts, and no potassium. Statistical analysis of the data showedthat the rate of starch production was appreciably increased bypotassium sulphate but not by the fertilisers containing chlorides.The rate of translocation of starch from the leaflets on the potassiumsulphatc plots was also increased, but this also varied significantlywith other factors, of which intensity of solar radiation and age4Q J .Indian Chern. SOC., 1927, 4, 298.41 Biochem. Z., 1927, 183, 135, 153; A., 595.42 Ber., 1927, 60, [B], 755; A., 428.43 Ann. Bot., 1927, 41, 237; A., 704230 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.were important. The results were in the main borne out bymanurial trials on the same land.The seasonal changes in starch content in one- to five-year-oldbranches of bush-type apple trees have been followed by T. Swar-Starch disappearance tended to lag behind cambial activityin vegetative shoots, whereas the reverse was the case in floweringshoots.It is maintained by Spengles and Wiedenhagen45 that sugaris transported from the leaves to the roots of sugar-beet in theform of hexoses and not as sucrose, the latter being synthesised inthe A similar view of the processes occurring in Cannaedulis is advanced by J.C. Rippert~n,~' who states that sucrose isformed in the leaves, and is transported through the stem in theform of invert sugar, resynthesis taking place in the root-stock withthe formation of sucrose and starch.Leaf Cytoplasm.A. C. Chibnall and H. J. Channon48 have made a study of theether-soluble substances of the leaf cytoplasm of cabbage. Havingworked out a method which enabled them to prepare these sub-stances in bulk, they showed that the fraction obtained by addingacetone to the ethereal solution contained no phospholipins butthat the main constituent was the calcium salt of a diglyceride-phosphoric acid to which the name of phosphatidic acid is assigned.The fraction not precipitated by acetone contained fatty acidswhich are not in combination with phosphorus compounds.Theunsaturated acids, linolenic and linoleic acids, predominated ;palmitic and stearic constituted the saturated acids ; oleic acid wasnot definitely identified ; arachidonic acid was absent. Hydrolysisof phosphatidic acid showed the presence of the same acids.The. Nitrogenous Metabolism and Constituents of Plants.A series of papers dealing with the nitrogenous metabolism ofapple trees has been published by W. Thomas.49 The distributionof nitrogen in the water-soluble fraction of leaves and shoots wasstudied a t intervals throughout a growing season, and in a subsequentseason comparison was made between an unfertilised tree and onereceiving a heavy dressing of sodium nitrate.Samples were4p J . Pornology, 1927,6, 137; A., 797. See also E. L. Proebsting, Hilgardia,1925, 1, 81; A., 1927, 488.4s 2. Verein Deu&. Zuckerind., 1926, Lief. 842, 767; Bied. Zentralbl., 1927,56, 459; compare Davis, Daish, and Sawyer, J. Agric. Sci., 1916, 7, 225.See also H. Colin and R. Franquet, Bull. SOC. Chirn. biol., 1927, 9, 114;A., 699; H. Colin, Cornpt. rend., 1927, 184, 835; A,, 696.47 Hawaii Exp. Sta. Bull. 56, 1927.4a Biochem. J., 1927, 21, 226, 233, 479, 1112; A., 386, 799, 1227.49 Plant Physiology, 1927, 2, 56, 67, 109, 246BIOCBIEMISTRY. 231desiccated a t 60" and, after suitable grinding, extracted with water.The separation of simple and conjugate proteins from their hydro-lytic products was effected by means of colloidal ferric hydroxide.An examination of the nitrogen distribution in several differentsamples of residual material after extraction with water showedvery consistent results, which in the opinion of T.B. Osborneindicated that a single protein is present, although the figuresdo not give absolute proof.The detailed results of the investigation of the changes occurringthroughout the year make interesting reading and work of this typewill undoubtedly lead to clearer views of the changes occurring duringthe various periods of growth. When growth is rapid, nitrogentends to migrate from the leaves to the shoots, where it is storedin the phloem.During bud formation, the reserve proteins aretransported to the actively growing parts in the form of amino-acids. The phenomenon of autumnal migration of nitrogen fromthe leaves to the branches, a point of controversy with earlierinvestigators, is established and storage takes place mainly in theone- and two-year growths. Although the quantities, not only ofsoluble proteins, but also of the total water-soluble nitrogenousproducts, are small in Pyrus malus and make this species anunsuitable plaht for investigation of the mechanism of protein syn-thesis, these results tend to confirm Chibnall's theory that amino-nitrogen is chiefly concerned in protein synthesis and " rest"nitrogen in protein degradati~n.~~ The results showed that nitrogenequilibrium of the whole tree would be just maintained by theapplication of 5 lb.of sodium nitrate.In the following year's work, distinct differences in conformitywith the fertiliser treatment were observed between two trees,one unmanured and the other receiving two heavy applicationsof sodium nitrate. The increased growth resulting from thetreatment was reflected in the analyses, and the possible applicationof the results to horticultural practice has been dealt with in anotherpaper.510. K. Stark 52 has carried out an investigation on the proteinmetabolism of the soya bean. Seedlings were grown under con-trolled conditioas in darkness and determinations of amino-nitrogenwere made at frequent intervals.In general, no correlation couldbe observed between period of growth and content of amino-nitrogen except in the very early periods; but since analyses werecarried out on the whole plants, and not on the separate parts ofAnn. Reports, 1924, 21, 192.6 1 PTOC. Amer. SOC. Hort. Sci., 1926, 73.63 Arne?. J . Rot., 1927, 14, 632232 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.the seedlings, this result is surely to be expected. The protein ofthe reserve material is broken down in one part and transferredto another ; hence analyses of the whole plant will presumably giveonly equilibrium values at any particular time, except in the veryearly stages when little growth has occurred.Among other papers on nitrogenous metabolism and nitrogencompounds in plants, the following may be briefly noted.C. 0.Appleman and E. V. Miller 53 have investigated the changes inthe nitrogen compounds in potatoes during growth and storage,the results failing to indicate any chemical or physiological basisfor the superiority of immature potatoes for “seed.” W. F.Gericke 54 has shown that the amount of nitrogen available a tdifferent stages of growth affects the protein content of wheat,the effects varying with different types of wheat. W. L. Davies 55has given an account of the proteins of forage plants of the ordersLeguminosce, Crucifer@, and Umbelliferce, with analytical details.S. L. Jodidi 56 has compared the proteins of rice with those of othercereals, and has isolated asparagine from etiolated maize seedlings.C .G. Vinson 57 has studied the nitrogenous compounds extractablefrom maize pollen by dilute sodium hydroxide solution.Storage of Fruit.In addition to its purely scientific interest, the Report of theFood Investigation Board for the years 1925-26 58 illustrates thegrowing connexion that is being established between industry andbiochemistry. The fruit trade suffers perhaps more than othersfrom loss by wastage, and the preservation of perishable goodsoffers many interesting problems.In this Report, investigations are described into the variousfactors favouring or preventing deterioration of fruit on storage,the work including both chemical studies on apples and pears ofdifferent varieties during ripening and storage and investigationsinto the suitability of various kinds of store.The best-keeping varieties of apples are found to contain the leastnitrogen and the most sugar and exhibit the lowest respiratoryactivity.Death ensues when the sugar is exhausted and this occursthe earlier if a large amount of protoplasm is present. Hence by asimple chemical determination the expectation of life of an appleduring storage can easily be found.The nature of the soil upon which the apples were grown had a53 J. Agm’c. Res., 1926, 33, 569; B., 1927, 22.54 Ibid., 1927, 35, 133; B., 826.55 J. Agric. Sci., 1926,16, 280; A., 1926, 761; ibid., 1927,17,33,41; B., 232.56 J. Agm’c. Res., 1927, 34, 309; A,, 800; ibid., 1927, 34, 649.6 7 Ibid., 1927, 36, 261; A., 1227.68 D.S.I.R., H.M. Stat. Office, 1927BIOCHEMISTRY. 233marked effect on the nitrogen content and hence on their keepingqualities. In general, specimens of the same variety from silt soilsurvived longer than those grown on gravel or fen soil at storagetemperatures of 1" and 8". At about the latter temperature, itwas found possible to double the storage life by keeping the fruitin an atmosphere containing 9.2% of carbon dioxide and 11.8%of oxygen instead of air. Death of the fruit stored at 1" is accom-panied by a browning of the tissue, a condition known as internalbreakdown ; in storage at 8" wastage is caused by a disease, " fungalrot," and not by internal breakdown. Slightly different resultswere obtained with pears, and indeed optimum storage conditionsvaried considerably amongst the several varieties.Differences in the rates of respiration of different varieties of appleshave been noted by B.D. Drain.59 F. Gerhardt 60 also has investig-ated some of the changes involved ikl the ripening and storage ofapples. He finds that the ripening process is accompanied by lossof moisture, acidity, dextrins, starch and acid-hydrolysable material,together with an increase in specific gravity, sugars, and solublepectin. Only very slight chemical differences between normaltissues and those showing internal breakdown could be detected.Work on the pectic substances of fruits has received attention inrecent ReportsJG1 and the subject continues to prove of interest.M. H. Carre and A.S. Horne 62 confirm earlier chemical investig-ations by a microscopical study of the tissues at various stages,and according to C. 0. Appleman and C. M. Conrad 63 the trans-formation of protopectin into pectin appears to be the only pecticchange associated with the ripening and softening of peaches.Other work on the chemistry of pectic substances is described byE. K. Nelson,64 A. M. Emmett,65 and by F. R. Davidson andJ. J. Williamson.66F. E. Denny6' has published an interesting summary of hisinvestigations on the curious effect of ethylene and other unsaturatedhydrocarbons in producing colour changes and a break in the restperiod of stored fruits and tubers. Other papers dealing with thissubject are noted below.68K g Bot. Gaz., 1926, 82, 183.6o Plant Physiology, 1926, 1, 251.61 Ann. Reports, 1925, 22, 213; 1926, 23, 228.62 Ann. Bot., 1927, 41, 193.64 J . Amer. Chem. Soc., 1926, 48, 2412, 2945.6 5 Biochem. J . , 1926, 20, 564; A,, 1926, 872.6 6 Bot. Gaz., 1927, 83, 329. 6 7 Proc. Nat. Acad. Sci., 1927, 13, 355.6* E. M. Chace and C. G. Church, Ind. Eng. Chem., 1927, 19, 1135; L. 0.Regeimbal and R. B. Harvey, J . Amer. Chem. SOC., 1927, 49, 1117; A., 599;L. 0. Regeimbal, G. A. Vacha, and R. B. Harvey, Plant Physiology, 1927, 2,357; G. A. Vacha and R. B. Harvey, ibid., p. 187.Maryland Agr. Exp. Sta. Bull. 283, 1926.H 234 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Structural Constituents of Plants.In last year’s Report mention was made of current theories withregard to the origin of lignin and the work of M.H. O’Dwyer onthe hemicelluloses of beechwood was referred E. Schmidtand his collaborators 70 have been working for some years on theconstitution of the structural components of plants and they con-sider that the cell-membrane of both archegoniates and phanerogamsis made up of cellulose, hemicellulose, and incrustation. A cellulose-hemicellulose complex termed the ‘‘ skeletal substance ’’ is obtainedby repeated treatment with chlorine dioxide and sodium sulphitealternately, incrustants and part of the hemicellulose being removed.The existence of two types of hemicellulose (compare O’Dwyer) istherefore postulated. Glycuronic acid occurs in the hydrolyticproducts of the hemicellulose pf a number of plants differing widelyin nature, including both archegoniates and phanerogams, thusindicating that, although the free acid is not present, a carboxylatedpolysaccharide, as its precursor, is common to both groups.Anester-like union of cellulose, glycuronic acid and hemicellulose isassumed to be present. Trustworthy figures for the determinationof polyglycuronic acids were obtained by treatment of the skeletalsubstance with alkali hydroxide, followed by conductimetric titr-ation with hydrochloric acid. W. Fuchs and E. Honsig 71 havecriticised Schmidt’s views on the ground that lignin obtained bythe above treatment does not resemble lignins prepared in otherways. This would seem to be a fair criticism because of the drasticnature of the reagents employed.It is very improbable, however,that lignin has ever been isolated in the condition in which it existsin the plant, and, in this connexion, it may be noted that C. Dor6eand E. C. Barton-Wright 72 have obtained a new type of alkalilignin by treating spruce dust with sodium hydroxide underpressure. This has been termed meta-lignin and is stated to agreein composition with the a-lignin of Klason. A useful summaryof present-day views on the origin and formation of plant-cellmembranes from both the botanical and the chemical aspect of thesubject has been published by van Iter~on.?~Absorption of Ions by Plants.In 1923, Robbins 74 advanced a theory explaining the differentialabsorption of ions by plants which was based on the isoelectric6B Ann.Reports, 1926, 23, 231.‘O E. Schmidt, F. Trefz, and H. Schnegg, Ber., 1926, 59, [B], 2635; A.,1927,80; E. Schmidt, K. Meinl, and E. Zintl, ibid., 1927,60, [ B ] , 503 ; A,, 383.71 Ibid., 1926, 59, [B], 2850. 72 Biochem. J . , 1927, 21, 290; A,, 597.73 Chem. Weekblad, 1927, 24, 166.74 Amer. J . Bot., 1923, 10, 412; Ann. Reports, 1923, 20, 226BIOCHEMISTRY. 235relations of the components of the living cells, particularly theproteins. If the acidity of the medium does not increase beyondthe pH represented by the isoelectric point of the cell colloids, mostof the latter are on the electronegative side of their isoelectricpoints and therefore combine with an excess of basic over acidradicals. The medium increases in acidity, and hence some colloidspass over to the electropositive side, an absorption of anionsresulting. J.Davidson 75 makes use of this hypothesis to explainthe fact that relatively more potassium than phosphorus wasabsorbed by wheat seedlings grown in potassium phosphate solu-tions, irrespective of the initial hydrogen-ion concentration of themedium. Owing to buffer action, this preferential absorption didnot result in any marked increase of acidity when the initial reactionwas pE 6 or 7, but, with initial reactions of p,5 or less, increasedacidity was observed. At this lower pB relatively more phosphoruswas absorbed than a t pH 6 or 7. It would thus appear that thephysiological availability of phosphorus depends on the px value ofthe medium. In explaining absorption phenomena of this type,the author assumes that there is a relatively wide range in theisoelectric points of the individual protoplasmic ampholytes of thecells.K. Lemanczyk 76 considers that absorption of potassium fromnutrient solutions by the roots of barley consists of two phases,viz., equivalent absorption, including absorption of salt moleculesas such, and ionic absorption. In the latter phase, to which thechanges in the reaction of the solutions are due, potassium ionsand anions in the solutions are exchanged respectively for calciumand magnesium ions and hydrogen carbonate ions in the root-cells.The results of the experiments of A.R. C. Haas and M. S. Reed 77on the absorption of ions by citrus and walnut seedlings are moredifficult to understand. Citrus seedlings removed relatively morepotassium than calcium from solut'ions containing approximatelyequivalent amounts of these ions.A n interchange of ions wasobserved between the solutions and roots which resulted in anincreased excretion of potassium in the solutions when the originalconcentration was low. Calcium ions were readily absorbed whensodium and potassium were absent or low in amount. With walnutseedlings, presence of excess of sodium chloride hindered absorp-tion of calcium. More kations than anions were taken up from thesolutions of single calcium salts by both citrus and walnut seedlings,causing an increase in acidity. The changes in reaction of the7 5 J. Agric. Res., 1927, 35, 335; B., 950.Bull.Acad. Polonaise, 1926, B, 1109; A., 1927, 1228.7 7 Hilgardia, 1926, 2, 67; A., 1927, 907236 ANNUAL REPORTS ON THE PROGRESS OB CHEMISTRY.culture solutions are attributed directly to differential absorptionof ions, together with an excretion of certain ions. It appears thatin complete nutrient solutions, citrus seedlings may in a compara-tively short period bring about so great a concentration of hydrogenions aa to be injurious to the roots. In the view of these workers,“ the absorption of ions is veiled by a host of factors, few of whichare as yet understood,” but they are of the general opinion thatabsorption is related to some chemical or physical property of theprotoplasm. A purely physicochemical explanation is apt, however,to take little notice of chemical change and growth within theplant.Absorption is taking place, not in one cell only, but inchains of connected cells, and it is here perhaps that the explanationof some of the difficulties may be found.In connexion with penetration into and absorption by livingplant cells, Osterhout and his associates ‘8 have investigated theprotoplasmic surfaces in the alga, Valonia rnacrophysa. Theprotoplasm forms a delicate layer, only a few microns in thickness,the two surfaces being alike as far as microscopic observation goes.By measurements of potential differences the conclusion is reached,however, that the protoplasm actually consists of three layers.Electrometric determinations on the chain sap-protoplasm-sapshowed a potential difference of about 14.5 millivolts, the innersurface being positive with respect to the outer.The chain isassumed to bewhere X is an outer, non-aqueous layer, W a middle aqueous layer,and Y an inner non-aqueous layer. The work of M. Irwin hasbeen referred to in a previous Report.79 She has continued herstudies of the penetration of dyes into the vacuole of living cells ofNitella and VuZoniu,*O investigating particularly the effects of acids,salts, and buffer mixtures on such penetration. The assumptionof the existence of separate layers in the protoplasm proper isutilised to account for her results.also discusses the mechanism of the accumulationof dyes by living cells.SaplXIWIYlsap,G. W. ScarthInorganic Constituents of Plants.A considerable volume of work has appeared in the last few yearson the distribution and function of the inorganic constituents of78 W.J. V. Osterhout, E. B. Damon, and A. G. Jacques, J . Gen. Physiol.,1927, 11, 193.is Ann. Reports, 1926, 23, 224.81 Plant PFuysioEogy, 1926, 1, 215.J . Gen. Phyaiol., 1926,10,76,271; 1927,10,425,927; 1927,11, 111,123BIOCHEMISTRY. 237plants, the subject being of special interest on account of theimportance now attached by workers in animal nutrition to themineral constituents of food rations. There is a tendency to takeup problems of balance and correlation and emphasis is being laidon the relative quantities of the various elements present.Primary Nutrient Elements.-0. Arrhenius 82 has published twopapers dealing with experiments on the optimum concentrationsof the primary nutrients for plant growth.He reaches the con-clusion that in most soils the concentration of potassium is s~.&-cient, whereas the concentration of phosphoric acid is about halfthat required for a favourable crop. The. purpose of fertilishgshould be to alter the concentration of the nutritive substances tothe optimum, and not necessarily to satisfy the demands of the plant.Working with Helianthus, A. Rippel s3 has shown that the absorp-tion of elements which are readily mobile in the plant, such asnitrogen, potassium, and phosphorus, accelerates the formationof dry matter, whereas less mobile elements such as calcium,magnesium, sulphur, and silicon have little or no effect.It is suggested that there is a relatively greater uptake of mobile elementsduring the earlier stages of growth of the plant.84J. Davidson 85 has investigated the changes in nitrogen, potass-ium, and phosphorus during the germination and early stages ofgrowth of wheat seedlings and finds that they may either lose orgain potassium and nitrogen, according to age and conditions, butthat the content of phosphorus remains approximately constant.In an interesting paper, K. Maiwald86 discusses the influence oflarge amounts of potassium and chlorine on the growth and leafcolour of potatoes. He found that excess of potassium or sodiumions alone effected a reduction in leaf colour, as compared withnormal plants, of about 25%, chlorine ions alone about 70% andpotassium and chlorine ions together about 60%.It was clear thatwith calcium chloride the effects were due solely to the chlorine ionsand that with potassium and sodium sulphates the influence of thekations predominated. The author considers that, not only reduc-tion in chlorophyll content, but many other phenomena concernedwith plant metabolism, can be attributed to the alteration of theequilibrium between physiologically important ions.J. H. MacGilliaays7 has shown that in phosphorus-starved82 Medd. Centralanstalt f$rs@ksvasende€ jordbruks, 1927, Nos. 40, 41.83 Biochem. Z . , 1927, 187, 272; A., 1116.On the influence of fertilisers on absorption of plant nutrients and form-ation of dry matter, see W. Schleusener, Z.Pflanz. Dung., 1926, A , 7, 137;B., 1927, 55. 8s Bot. Qaz., 1926, 81, 87.86 Z . Pflanz. Diing., 1927, A , 9, 67; B., 565.a 7 J . Agm'c. RM., 1927, 34, 97; A., 699238 ANNUAL REPORTS ON THE PROGRESS OF HEMIS IS TRY.tomato plants there is a re-utilisation of the phosphorus present ;about half the total amount is found in the fruit, irrespective oftreatment, although, if there is a shortage of phosphorus, the sizeand number of the fruits are much decreased. There is an increasein the percentage of total nitrogen and of sugars present. Theeffects of deficient amounts of potassium, calcium, and magnesiumon various plants have been studied by R. C. Burre11.88The occurrence and distribution of sodium in plants and theratio of the amounts of sodium and potassium present have beenthe subjects of several papers.89 By comparing the compositionof the seed with that of barley plants grown in darkness, with andwithout sodium and potassium, t o the point of exhaustion of thereserve materials, A.Bobrownicka-Odrzywolska 90 has shownthat in presence of potassium a smaller amount of carbohydrate isrequired for the formation of a unit of cellulose. Sodium has asimilar effect if accompanied by other necessary mineral salts.Potassium also reduces the loss of organic matter and the per-centage of starch decomposed for respiration purposes. The youngplants made poorer growth in pure potassium or sodium chloridesolutions than in distilled water; none the less, a smaller per-centage of starch was decomposed for respiration.The translocationof potassium from leaves of ivy and poplar has been followed byT. Sabalitschka and A. Wei~e.9~Secondary Elements in Plant Nutrition.-The appearance offurther papers asserting the indispensability to plants of certainelements hitherto neglected in this connexion would seem to involvereconsideration of what were regarded as established facts in plantnutrition. The pioneering work of Mazk92 indicated the possi-bility that, by more refined methods, the ten elements postulatedby Knop and the older physiologists as satisfying all the require-ments of plant growth might be shown to be insufficient. Theseexperiments, coupled with the stimulus due to the brilliant workon deficiency diseases which has demonstrated the importance ofminute amounts of vitamins, hormones, and mineral elements inthe animal body, have led to a number of investigations on the r61eof secondary elements in plant growth.03Bot.Gaz., 1926, 82, 320; A., 1927, 596.G. Bertrand and J. Perietzeanu, Compt. rend., 1927, 184, 645, 1616;Bull. SOC. chim., 1927, 41, 709; A., 488, 704, 1116; G. Andre and E.Demoussy, Compt. rend., 1927, 184, 1501 ; A., 798.@O Bull. Acad. Polonaise, 1925, B , 801; A., 1927, 384.s1 2. Pfianz. Dung., 1926, A, 7, 166; B., 1927, 66.s2 Ann. Reports, 1916, 12, 231.Earlier papers are referred to in Ann. Reporb, 1922, 19, 225; 1923, 20,219; 1926, 22, 210BIOCHEMISTRY. 239The general line of the experiments now under notice is toattempt to grow plants in the usual nutrient solutions, preparedfrom highly purified chemicals, so that contamination with otherelements is reduced to a minimum.Under these conditions, manyplants fail to grow. The addition of very small traces of certainelements-boron, zinc, silicon, aluminium, manganese-has, in anumber of instances, secured normal growth of the plants and allthe above-named elements have been stated by different workersto be indispensable for proper growth.In regard to boron, the earlier work of Miss Warington hadshown that certain leguminous plants, but not barley and othercereals, could not be grown to maturity in solutions free from thiselement. Following up these observations, W. E. Brenchley andK. Warington 94 have attempted to replace boron for plants whichrequire it by other elements, particular attention being paid tomanganese; but, of 52 elements tested, none proved capable of sodoing.On the other hand, G . H. Collingsg5 states that, contraryt o Miss Warington’s findings, boron is not essential for the growthof the soya bean, although in water cultures a stimulating influencewas observed. A. L. Sommer and C. B. Li~man,~6 taking elaborateprecautions to purify all the materials used, have demonstratedthat both boron and zinc are indispensable to many leguminousand non-leguminous plants, barley (see above) requiring both theseelements. They are of the opinion that the explanation put for-ward by Brenchley andThornton in 1925,97 that the failure of legumesto grow in absence of boron is closely connected with injury to thenodule bacteria and consequent disturbance of the nitrogen meta-bolism of the plant, avoids the main issue.A.L. Sommer gs records experiments showing that small tracesof aluminium and silicon are also necessary for normal growth;and J. S. McHargue, from analyses of cotton99 and blue-grass,lconcludes thaC manganese, copper, zinc, nickel, and cobalt may allbe essential elements. Lack of manganese has been shown to bethe cause of chlorosis in one instance,2 and Bortels states that zincis necessary for the growth of the mould AspergiZZus niger.J. Stoklasa and his associates have for some time past concerned9 4 Ann. Bot., 1927, 41, 167; A., 385.s5 Soil Sci., 1927, 23, 83; B., 307.96 Plant Physiology, 1926, 1, 231.s7 Proc.Roy. SOC., 1925, B, 98, 373; Ann. Reports, 1925, 22, 210.s8 Univ. Calif. Pub. Agr. Sci., 1926, 5 , 57.J . Amer. SOC. Agron., 1926, 18, 1076; A., 1927, 599.Ind. Eng. Chem., 1927, 19, 274; B., 394.B. E. Gilbert, F. T. McLean, and L. J. Hardin, SoiE Sci., 1926, 22, 437;B., 1927, 171. Biochem. Z., 1927, 182, 301; A., 486240 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY,themselves with the occurrence of iodine in plants and the dis-tribution of this element in the earth's crust. Their views aresummarised in a recent paper,* in which it is pointed out that thepresence of iodine can be detected both in volcanic rocks and inmore recent rocks containing the fossilised remains of animal orplant life. They state that iodine promotes the growth of nitrifyingbacteria and that the simultaneous presence of iodine and iron inthe soil leads to a general enhancement of fertility; indeed, theyregard iodine as an essential biogenic element in the synthesisingprocesses of living cells.In this they are supported by K. Scharrerand his co-~orkers,~ who show that iodides, iodates, and periodatesmaterially increase the rate of reproduction of yeast, althoughwithout increasing the final maximum figure. Although these andother experiments make a strong case for the consideration ofiodine as an important element in the economy of plants, there isevidence that conflicts with this view and the claims put forwardcannot be completely accepted until further confirmation is forth-coming.It will be seen from this short summary that an interesting posi-tion has been reached.The work on '' secondary " elements isstill in an early stage and it is not surprising that somewhat con-flicting results have been obtained by investigators working underdifferent conditions. Experimental demonstration is difficult owingto the minute amounts involved, and conditions for growth indifferent parts of the world vary widely. Some plants may have asufficient reserve of " secondary " elements in their seeds to carrythem through a growing season, and therefore it is difficult to pro-duce rigid proof of the essential nature of these elements; but it isprobable that some, if not all, of the elements cited are necessaryfor the full and proper growth of different species of plants underdifferent conditions.Some clue as to the function of such elements is giqen by Brench-ley and Warington,' who observed that boron appears to beassociated with absorption or utilisation of calcium, possibly some-what as silicon appears to be associated with phosphorus nutrition.The inter-relations between silicon and phosphorus form the sub-ject of a paper by W.E. Brenchley, E. J. Maskell, and K. Waring-ton,s whose results are on the whole in agreement with thoseZ . angew. Chem., 1927, 40, 20; A., 171.K. Scharrer and J. Schwaibold, Biochem. Z . , 1927, 185, 405; A., 798;See also K. K. Scharrer and W. Schwartz, ibid., 1927, 187, 159; A., 903.Scharrer, Portschr. Landw., 1927, 2, 119, 249.6 See, e.g., W.E . Brenchley, Ann. Applied Biol., 1924, 11, 86.7 LOC. cit.Ann. Applied Biol., 1927, 14, 45BIOCHEMISTRY. 241reported previously.9 From statistical examination of the data,from pot experiments, they conclude that the effect of addedsilicate can be formulated in terms of an increase in the efficiencyof the phosphoric acid present.A valuable review of the literature regarding the effect on plantsof copper, zinc, arsenic, boron, and manganese is given by MissBrenchley in a recent publication.10General Changes with Growth.An investigation of agricultural and biochemical interest has beenpublished by H. E. Woodman, D. L. Blunt, and J. Stewart l1dealing with the seasonal variations in the productivity, botanicaland chemical cdmposition, and nutritive value of medium pasturage,both on light and on heavy soils.During late years, increasinginterest has been shown in our pasture lands, and although experi-ence and shrewd observation had led to the evolution of suchsystems of grazing as the “ Hohenheim system,” definite inform-ation of a chemical and botanical nature on the above factors waslacking. By far the greater part of the work done on the nutritivevalue of grassland has concerned itself with the hay crop, and littlewas known of the chemistry of the immature growth which obtainsunder grazing conditions. In the investigations now being con-sidered, an attempt has been made to imitate close grazing bycutting plots a t frequent intervals with a lawn mower.The pro-duce so obtained was subjected to botanical and chemical analysis,and, in addition, digestibility trials were carried out.It was found that, under these conditions, the grass contains avery high percentage of protein throughout the whole season, andthe percentage of fibre is much lower than in meadow hay. Theherbage in fact closely resembles a concentrated food, like linseedcake, that has been “watered down” and it has a much highernutritive value than had previously been supposed. Unlike manyfarm concentrates, pasture grass is well supplied with vitaminsand is also rich in bone-forming minerals. The experiments of1925 on light land were repeated on heavy land in 1926 with sub-stantially the same results, and the authors make the interestingsuggestion that a future development may be the production ofhome-grown concentrates for winter maintenance simply by dryingor ensiling short grass cuttings. E.J. Sheehy13 found that thebotanical composition and the nutritive value of the herbage ofSee Ann. Reports, 1925, 22, 210.10 “ Inorganic Plant Poisons and Stimulants,” Camb. Univ. Press, 1927.l1 J . Agric. Sci., 1926, 16, 205; 1927, 17, 209; B., 1926, 606; 1927, 688.l2 Ann. Reports Applied Chem., 1926, 11, 462.l3 Sci. Proc. Roy. Dub. SOC., 1927, 18, 389; B., 791242 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.two pastures of different reputation could be correlated with thedry matter content of the grass.Several investigations dealing with chemical changes during thegrowth of fruit may be noted here.R. H. Roberts l4 states thatblossom bud formation in apples accompanies a condition of balancebetween the nitrogen and carbohydrate content ; and G. T. Nightin-gale 15 has shown the importamce of the same balance in determiningthe growth of tomato plants under conditions of long and of shortillumination. The physical and chemical changes occurring duringthe ripening of grapes have been studied by P. R. V. D. R. Copemanand G. Frater.16B i o c h e m i s t r y of A n i m a Is.Vitamins.This year’s work in the field of vitamins has been characterisedby increasing activity and much important information has beenadded to that of preceding years. Although recent developmentshave not yet resulted in the isolation of any of the vitamins inwhat can be asserted with confidence to be a state of purity, thereare several indications that this advance cannot be long delayed.Vitamin-A.-Two publications have appeared from Japan bythe workers who are continuing there the investigations commencedby the late Dr.Takahashi, and these appear to the Reporter to callfor some comment. It was previously stated 1 that the prepar-ation made from the unsaponifiable fraction of cod-liver oil, towhich the formula C2,H4,(OH), was ascribed and which was called(‘ biosterin,” constituted essentially the pure vitamin. Verysimilar preparations had been obtained by Drummond and hisco-workers and an examination of these led to the conclusion thatthey were essentially unsaturated complex alcohols and hydro-carbons with which the vitamin was admixed in unknown butprobably small amount.Nakamiya and Kawakarni have nowmade a study of the hydrogenation products of “ biosterin,” andin a publication entitled (‘ Hydrogenation of Sterol-free Unsaponi-fiable Matters of Cod-Liver Oil ” they describe the isolation fromhydrogenated (‘ crude biosterin ” of nonacosane, batyl alcohol,myricyl alcohol, an unknown saturated alcohol of m. p. 89-91’,and octadecyl palmitate. Purther, cholesterol appears to haveIbid., Bull. 74, 1927; A,, 1225.Ann. Reports, 1925, 22, 219.Ibid., p. 219.14 Wisconsin Agr. E x p . Sta. Res. Bull. 68, 1926; A., 1927, 283.16 Dep. Agr. Union S. Afr. Sci. Bull. 50, 1926; A., 1927, 908.3 Sci. Papers, I m t .Phys. Chem. Rerrearch (Japan), 1927, 3, 62BIOCHEMISTRY. 243been isolated from the unhydrogenated “ crude biosterin ” whenthe latter was subjected to further purification. In a secondpublication, “ On the Hydrogenation of Biosterin ” 4 the isolationof the same products is described from a preparation called “ purifiedbiosterin.” In view of these results, it is a little difficult to under-stand why the terms ‘‘ unsaponsable ” and “ sterol-free ” are useda t all in the title of the first paper, and it would appear more thanprobable that in “ biosterin ” the Japanese workers are handlingthe same fraction of unsaturated alcohols and hydrocarbons asthat studied by Drummond and his associates. The Reporter hasthought it necessary to refer to these observations, since theywould seem to dispose of the view, advanced with much circum-stantial evidence, that “ biosterin ” really constituted vitamin-d ,and they illustrate afresh the great technical difficulties which besetattempts to separate the vitamin in a pure state.Nakamiya andKawakami confirmed the observation that the growth-promotingpower of their fractions was completely lost after hydrogenation.Rosenheim and Web~ter,~ as the result of a large series of bothcolorimetric and biological tests, have found that the amount ofvitamin-A present in liver fats other than that of the cod, in manycases far exceeds that present in the latter source. They statethat the liver oils of fishes such as the salmon and halibut are often100 times as rich in the vitamin as that of the cod.A discoveryof much greater potential industrial importance is that the liveroils of herbivorous mammals, such as the sheep, calf, and ox, usuallycontain some ten times the concentration of the vitamin found incod-liver oil. It is suggested that such mammalian oils, being freefrom the highly flavoured clupanodonic acid characteristic of fishoils, and from the chromogen responsible for the non-specificFearon colour reaction,6 are well suited for incorporation withmargarine and so constitute a ready means of raising the latter tothe same standard of biological efficiency as butter, so far as vita-min-A is concerned. There is, in fact, no reason why a higherstandard should not be attained. Using the antimony trichloridetest, Wilson has found that the human liver has the same highcontent of vitamin-A as the livers of other mammals.Althoughthe amount is rather variable, fatty extracts from human liver maycontain as much as 25 times the amount found in cod-liver oil.The mechanism of the arsenic or antimony trichloride colourreaction for vitamin-A still remains obscure. Rosenheim hasSci. Papers, Inst. Phys. Chern. Research (Japan), 1927, 7 , 121.ti Nature, 1927, 120, 440; Biochern. J . , 1927, 21, 111 ; A,, 271.Rosenheim and Webster, Biochern. J., 1926,20, 1342; A., 78; Willimott,Biochern. J . , 1927, 21, 1054; A., 1223. a Ibid., p. 386; A,, 486.Moore and Wokes, ibid., p. 1292; A., 78244 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.attempted to elucidate this question in a study of the chromogenicsubstance produced when a chloroform solution of cholesterol andbenzoyl peroxide is evaporated to dryness.The substance obtainedgives with arsenic trichloride a blue colour indistinguishable inappearance from that given by an oil containing vitamin-A. Butwhen the purified chromogen is added to vegetable oils which donot themselves give the arsenic chloride reaction, no colour is thenobtained. The colour developed by the artificial product does notfade so rapidly as that given by an oil containing the vitamin.Further, there are differences in the absorption spectra of the twopigments, and it is evident that this artificial chromogen, althoughit must bear some family resemblance to the natural chromogenor vitamin, is not identical with the latter.All the availableevidence still supports the view that the chromogen and vitamin-Aare one and the same substance.In a study of the determination of vitamin-A by the biologicalmethod, Steenbock and Coward 9 recommend supplying vitamin-l)in the form of an irradiated sterol, and state that the incidence ofophthalmia in experimental animals forms a better criterion of the .depletion of the animal’s store of vitamin-A than does cessation ofgrowth.Vitamin-€3.-The past year has seen the definite recognition ofwhat has been widely suspected by workers on this vitamin, namely,the existence of two distinct components of what has hitherto beencalled water-soluble vitamin-B. The question of nomenclature a tonce arises and the present occasion seems to be a suitable one forconsidering the general principles to be adopted in naming newvitamins-a problem which shows signs of becoming increasinglyacute.For the worker in fields other than that of the vitamins,and for the medical practitioner, it must be highly disconcertingto find a vitamin, familiar to him under the term, shall we say, X ,becoming fragmented into two or more vitamins X , Y , and 2,amongst which are distributed, in a manner quite mysterious tohim, the properties formerly exclusively assigned to the original X .With the view of preserving a greater degree of continuity in theliterature, it seems desirable to evolve a system which will obviatethis difficulty and a t the same time clearly differentiate the con-stituents of any complex vitamin group. For these reasons, itdoes not seem that the suggestions of Sherman and Axtmayer lC areto be recommended.These are that the term “vitamin-B” bereplaced by the terms “ vitamin-F ” (heat-labile, anti-neuriticcomponent) and ‘‘ vitamin4 ” (heat-stable, pellagra-preventiveJ . Biol. Chem., 1927, 72, 765; A,, 595.lo Ibid., 1927, 76, 207; A,, 1223BIOCHEMISTRY. 245component). A recent suggestion of the Accessory Food FactorsCommittee l1 in this country seems more serviceable, and is to thefollowing effect : (1) the term " vitamin3 " should be retained forthe group of water-soluble vitamins to which the term was firstapplied by McCollum and Davis in 1915 ; (2) the term " vitamin-B, "should be used for the more heat-labile, anti-neuritic vitamin(called " torulin " by Kinnersley and Peters) l2 required to preventpolyneuritis in birds, marasmus, with or without paralysis, inmammals, and beri-beri in man ; (3) the term " vitamin-B, " shouldbe given to the more heat-stable component (called P-P by Gold-berger and his associates in America) necessary for the maintenanceof growth and health, and for the prevention of characteristic skinlesions in rats and of pellagra in man.The committee also recom-mend that the term '' bios " be retained for the substance or sub-stances encouraging the rapid growth of yeast-cells. These sug-gestions are only tentative and have not as yet been officiallyadopted ; nevertheless for the sake of simplicity and clarity the useof the terms B, and B, will be adopted in this Report.Since the adoption of the view that the growth-promoting,water-soluble vitamin-B was identical with the anti-neuritic vitamincurative of polyneuritis in birds-a suggestion first made byMcCollum and Kennedy in 1916-much evidence has accumulatedwhich is slightly but definitely a t variance with that view, and itis the steady accretion and strengthening of this evidence which hasled to the recommendations mentioned above.The evidenceagainst the identity of water-soluble-B (in the original strict sense)with the anti-neuritic vitamin may be grouped under three heads : 13(1) distribution in nature ; (2) differences in heat stability ; (3) differ-ences in solubility and other physical properties.As regards (l),wheat embryo is rich in B, but poor in B,, whereas the reverse istrue of milk, meat, green leaves, roots and tubers. Many yeasts ofequal B, content vary considerably in regard to B,. Under (2)come the observations that a t 120" B, is much more sensitive toinactivation than is B,, so that on autoclaving yeast for four orfive hours there is obtained a preparation devoid of B, but stillpotent as regards B,. (3) The physical differences are shown by thegreater solubility of B, in alcohol, acetone, and benzene, andfurther by the greater tendency of B, to be adsorbed by charcoalor fuller's earth.Institute of Preventive Medicine.904.Axtmayer, loc. cit.; Salmon, J .Biol. Chem., 1927, 73, 483; A., 796.l1 Appointed jointly by the Medical Research Council and the Listerl2 Biochem. J , 1925,19, 820; 1927, 21, 777; A., 1925, i, 1616; A., 1927,l3 Chick and Roscoe, Biochem. J . , 1927, 21, 698; A., 702; Sherman an246 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.The studies of human pellagra by Goldberger and his associates 14dating from 1924 have led to the abandonment of their earliertheory that this disorder was caused by the inferior biologicalvalue of the dietary proteins, and to the adoption of the view thatthere is present in water-soluble vitamin-B a pellagra-preventiveprinciple (which they call P-P), identical with the growth-promotingprinciple of McCollum and Davis. Chick and Roscoe l5 corroboratethe results of Goldberger in regard to pellagra.Important furthersupport of these views regarding the multiple nature and physio-logical r61e of the components of vitamin-B is forthcoming fromDrummond’s laboratory,l6 and it would appear that much con-flicting evidence regarding the physiological r61e of vitamin-Bwill become more easily interpreted on wider recognition of itscomposite nature. That the complexity of vitamin-B may nothave been completely unfolded by the recognition of vitamins-B,and -B, is suggested by the observation of Boas l7 that crude egg-white, boiled and supplemented by an adequate diet, is not capableof supporting growth and health in young rats if the egg-whitehas been dried before being boiled. On the other hand theefficiency of the egg-white is not impaired if it be coagulated previousto desiccation.The ill-effects resulting from the ingestion of driedegg-white are counteracted by raw potato, potato starch, arrowroot,dried yeast, fresh egg-white, egg-yolk, milk, commercial casein,crude lactalbumin, spinach, cabbage leaves, banana, and driedhorse serum. These substances are supposed to possess someprotective principle which, although similar in distribution to theB-vitamins, is not identified with either B, or 23,. It is furthersuggested that there is a balance between the amount of the driedegg-white ingested and the amount of the protective principlerequired. A somewhat similar problem was encountered byReader and Drummond,18 who found that a diet consisting largelyof casein became adequate when the ratio of yeast extract to proteinwas raised considerably, and related problems of balance of food-stuff by vitamin-B have been investigated by Plimmer, Rosedale,and Raym0nd.1~The isolation of vitamin-B, is claimed by Jansen and Donath, 20l4 Goldberger and Tanner, U.S.Pub. Health Rep., 1924, 39, 87; 1925, 40,54; Goldberger, Wheeler, Lillie, and Rogers, ibid., 1926, 41, 297 ; Goldbergerl6 Kon and Drummond, Biochem. J . , 1927, 21, 632; Hassan and Drum-l7 Ibid., 1927, 21, 712; A., 797.la Ibid., 1926, 20, 1256; A., 1927, 79.lo Ibid., 1927, 21, 913, 1141; A., 905, 1224.zo Proc, K. Akad. Wetensch. Arneterdam, 1926, 20, 1390; A., 1927, 382.and Lillie, ibid., p. 1025. 1 5 L O C . cit.mond, ibid., p.653; A., 702BIOCHEMISTRY. 247who describe the isolation of a residue weighing 1.4 g. from 100 kg.of rice polishings and containing about one-quarter of the amountof the vitamin originally present. The product is stated to be thehydrochloride of a base and to it the formula C,H,,ON,,HCl isascribed. Its chemical behaviour suggests the presence of a gly-oxaline nucleus. Eykman 21 states that this preparation curespolyneuritis in fowls.'Vitumin-C.-No very striking advance falls to be recorded inregard to the anti-scorbutic vitamin, but Bezssonoff 22 suggests thatthis vitamin too is a complex consisting of two substances, differingin their heat stabilities, one probably being derived from the other.Hoyle and Zilva 23 report that the concentrated anti-scorbuticfraction of lemon juice contains iron, phosphorus, and sulphur, andthat these elements dialyse along with the vitamin.On the otherhand, Vedder and Lawson 24 state that their concentrated prepar-ations, made by extraction with alcohol, could be freed from phos-phorus and sulphur without loss of activity. In an interestingquantitative study of the reducing power of the anti-scorbuticfraction of lemon juice towards phenolindophenol, Zilva 25 showsthat if sufficient of this indicator be added to destroy the reducingproperty of the solution, the reduced leuco-compound of theindicator is re-oxidised in the air and is then further reduced bythe solution. This alternate reduction and oxidation proceeds untilthe reducing power of the medium is destroyed.The reducingproperty of decitrated juice or of its active fractions is lost, like theanti-scorbutic activity, in an alkaline medium in the presence ofair, but on fractionation of the juice the substance responsible isfound in as high quantities in the inactive as in the active fractions.On adding the indicator to decitrated lemon juice until the formeris no longer reduced, and on testing the solution so treated immedi-ately, no very appreciable loss in the anti-scorbutic activity isobserved. Neither the reducing capacity nor the anti-scorbuticactivity undergoes any appreciable diminution when the decitratedjuice is kept for one hour in neutral or acid solution in an autoclavea t a pressure of one atmosphere.On storing, both propertiesdeteriorate very much more quickly than in untreated decitratedjuice. Zilva suggests that the stability of vitamin4 possiblydepends on a sequence of reactions which are normally kept inequilibrium in the living cell-a hypothesis of great interest in21 Proc. K . Acad. Wetensch. Amsterdam, 1927, 30, 376; A., 1224.22 Compt. rend., 1926, 183, 1309; A., 1927, 283.23 Biochem. J . , 1927, 21, 1121; A., 1224.J . Biol. Chern., 1927, 73, 215; A., 702.z6 Biochem. J., 1927, 21, 689; A., 702248 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.view of the suggestion of Bezssonoff, already referred to, regardingthe complex nature of this vitamin.Yitumin-D.-In order to present a more complete survey of thepresent position of the numerous investigations in progress withregard to the formation and properties of vitamin-D, it will beadvisable to include in the present Report some reference to mattersmentioned in the Report of last year.Early in 1927 there appearedthe detailed results of Heilbron, Kamm, and Morton,26 who wereable to show in a spectrographic study of cholesterol, before and afterirradiation with ultra-violet light, that purified cholesterol containsin small amount another substance which can be accumulated inthe least soluble fraction on crystallisation from ethyl acetate,that this substance possesses absorption bands in the ultra-violeta t 293 pp, 280 pp, and 269 pp, whereas cholesterol itself has onlygeneral absorption, and that these bands disappear on irradiationwith a concomitant appearance of anti-rachitic potency.It wassuggested that this unknown substance and not cholesterol itselfwas closely related to the precursor of vitamin-D. While this workwas in progress Rosenheim and Webster 27 in this country andWindaus and Hess 28 in Germany were making a, detailed examin-ation of the effects of irradiating a, large number of cholesterolderivatives and related compounds. In the course of this work itwas shown that the trebly unsaturated and highly labile ergosterol,C27H420, gave rise to a highly potent anti-rachitic substance. Itwas further shown that cholesterol and the phytosferols, stigma-sterol, C,,H,,O, and sitosterol, C2,H460, when brominated, andsubsequently reduced by the action of sodium amalgam and aceticacid in order to regenerate the original sterol, were quite unable,after irradiation, to prevent the development of rickets in rats.It was suggested that the labile provitamin had been destroyed inthe course of this treatment.In view of the high sensitivity ofergosterol to oxidative processes, of its ultra-violet absorptionspectrum, similar to, but more intense than, that of impure “activ-atable ” cholesterol, and of the very high degree of anti-rachiticpotency developed by ergosterol on irradiation (Rosenheim andWebster state that the curative dose for rickets, developed in rats,is of the order of 1/10,000 to 1/20,000 mg. per diem), both Rosen-heim and Webster and Windaus suggest that provitamin-D isergosterol or some closely related sterol.They suggest that it isthe presence of small amounts of the latter, in the proportion ofabout 1 part in 2000, in all specimens of cholesterol prepared from26 Biochem. J . , 1927, 21, 78; A., 381.e7 Ann. Reports, 1926,23,254; Biochern. J . , 1927,21,127,389; A., 381,487.OB Nachr. ges. Wise. Gcttingen, 1927, 175, 84BIOCHEMISTRY. 249natural sources that is responsible for the development of anti-rachitic properties. Irradiated ergosterol is certainly the mostpotent anti-rachitic substance known and it is estimated that about5 mg. are equivalent to about 1 litre of a good cod-liver oil. Dr.Katharine Coward is reported by Rosenheim and Webster to havedetected the calcifying effect of 1 /100,000 mg. of irradiated ergosterolby means of the “ line ” test.Rosenheim and Webster 29 have published a further study of themechanism underlying the conversion of ergosterol into vitamin-D,in the course of which it is shown that the maximum activity isattained within 30 minutes after exposure to the radiations of amercury vapour lamp, the usual precautions being adopted toexclude oxidative changes.Thereafter the activity does not increasepari passu with the disappearance of ergosterol, but remains con-stant up to 4 hours’ irradiation. It is suggested that after a shortinitial period the formation and destruction of the vitamin proceedat the same rate until the available supply of ergosterol is exhausted.It would in any case appear that the conversion of ergosterol intovitamin-D is not a simple unimolecular reaction. Rosenheim andWebster record the further important observation that the com-paratively long-wave radiations of solar ultra-violet light are capableof activating ergosterol.The high content of cholesterol present inhuman skin (13 to 24%), and the presence in this cholesterol ofsome substance possessing the same ultra-violet absorption asergosterol, being borne in mind, this observation is of the greatestinterest in relation to the curative effect of sunlight in rickets.In view of the results just described, it would seem that there isno serious obstacle to the belief that provitamin-D is identical withergosterol. Nevertheless, the observations of Jendrassik andKemdnyffi 30 lead these authors to suggest an alternative theory.In the first place, they confirm the statements of Rosenheim andWebster and of Windaus and Hess that irradiated ergosterol pro-vides a highly potent anti-rachitic preparation, but they have failedto confirm the observation that cholesterol, after bromination andsubsequent reduction, cannot be activated by irradiation. It isalso asserted that in a series of fractionation experiments inactivecholesterol, after removal of the active fraction by recrystallisationand washing, can be reactivated repeatedly.The period of irradi-ation used by these investigators is 1 hour and the cholesterol isirradiated in thin layers containing 0.01 g. per square cm., and itis apparently assumed that complete conversion of the provitamininto the vitamin occurs under these conditions.The successive29 Lancet, 1927, ii, 622; A., 1224.3o Biochem. Z., 1927, 189, 180; A., 1224250 ANNUAL REPORTS ON THE PROGRESS Or CHEMISTBY.development of anti-rachitic potency in inactive fractions, fromwhich the active substance developed in prsvious irradiations hasbeen removed, and especially their success in activating cholesterolafter bromination, lead Jendrassik and KemBnyfii to the remarkableconclusion that, although cholesterol itself is not the provitamin, itgives rise to the latter in the presence of water. They also statethat on withdrawal of the last traces of water from cholesterol theprovitamin is destroyed and the possibility of its re-formation islost together with a concomitant disappearance of the characteristicabsorption bands, unless it be again treated with water.Theseremarkable suggestions of Jendrassik and Kembnyfii merit attention,and it appears to the Reporter that, apart from the brominationexperiments, they are not incompatible with the results of Rosen-heim and Webster and of Windaus. It is therefore highly desirablethat the question of the activatable nature or otherwise of bromin-ated and reduced cholesterol should be subjected to rigorous testsunder widely varying conditions. It is to be noted that Jendrassikand Kern&@ subjected the cholesterol which they regeneratedfrom the dibromo-compound to two evaporations on the steam-bathwith wet alcohol. Hess and Anderson,3l who have separated sito-sterol from corn oil into a-, p-, and y-fractions, the first-mentionedbeing the most soluble and least stable of the three, confirm thefact that neither the p- nor the y-fraction could be activated byirradiation after purification by means of the respective bromo-compounds.The freshly prepared a-sitosterol could be activated(omitting the bromine treatment), but Hess and Anderson are notcertain of the degree of purity of their preparation.In view of the results described above, it is obvious that thenumerous observations published during the past year on theactivation and fractionation of cholesterol and of its derivativesmust be re-examined, but at the same time much valuable inform-ation has been accumulated which will no doubt be more readilyinterpreted when the chemical natures of vitamin-D and its pre-cursor have been elucidated, an achievement which cannot now belong delayed.Vitamin-E .-Little has been added to our information concerningthe anti-sterility vitamin.Sure 32 and Hartwell 33 both report thatfertility of rats is diminished, or complete sterility may be pro-duced, by diets in which cod-liver oil is the sole source of fat andfat-soluble vitamins. Sure was able to restore fertility by supple-menting the diet with 0.035% of the unsaponifiable matter from31 J . Biol. Chem., 1927, 74, 651; A., 1224.82 Ibid., pp. 37, 45, 71 ; A,, 905.83 Biochem. J . , 1927, 21, 1076; A., 1107BIOCHEMISTRY. 251cotton-seed oil, or by a large addition (10%) of butter.Hartwellconfirms the advantage of butter over cod-liver oil. Simmonds,Beckcr, and McCollum 34 state that the death of rat-fcetuses throughlack of vitamin-E is due to a crisis in their assimilation of iron, theadministration of ferric citrate or wheat oil being beneficial. Theyreport that liver oils are rich in vitamin-3, a result which seems tobe at variance with the results of other workers on cod-liver oil.Speci$c Carbohydrates from Bacteria.Professor Drummond dealt in the Report for last year with thehighly interesting advance in the chemistry of specific immunologicalreactions rendered possible by the work of Heidelberger, Avery, andtheir associates.35 Further progress in the study of the nature ofthe specific polysaccharides isolated by them has been made in thepast year.Heidelberger and Goebe136 have shown that the poly-saccharide of Type I11 pneurnococcus, on acid hydrolysis, yieldsglucose and an acid of the type of glycuronic acid having theformula Cl,H,,Ol,. It has one half of the reducing power of glucose,gives a positive reaction with naphtharesorcinol, contains analdehyde group, and on oxidation with nitric acid gives saccharicacid. On oxidation with barium hypoiodite 37 the original acidgives a dicarboxylic acid, C,,H,,O,(CO,H),, which still responds tothe naphtharesorcinol reaction and yields the same amount offurfuraldehyde as the original acid. It is therefore deduced thatthe latter is an aldobionic acid composed of one molecule of glucoseand one of glycuronic acid combined in glucosidic linking throughthe aldehyde group of the latter.The following formula is thereforeto be ascribed t o this substance :CO,H*CH*[CH*OH],*CH-O - CH,*CH*[CH*OH J,*CH*OHL - 0 2Glucose.-0-Glycuronic acid.The reducing group of the glycuronic acid residue may be attachedto the glucose residue in the position 6 shown, or to any one of thepositions 2, 3, and 4. The evidence does not yet permit of a choicebeing made between these possibilities.Goebel 38 has obtained from the specific polysaccharide of Fried-lander's type A bacillus an aldobionic acid which is composedlikewise of glycuronic acid and glucose apparently linked in thesame way as the components of the pneumococcus acid, with whichit is isomeric.One would suggest that the presence of one of the94 J . Amer. Med. ASSOC., 1927, 88, 1047; A., 1224.as Ann, Reports, 1926, 23, 248.as J . Biol. Chem., 1927, 70, 613; A., 77.ST Ibid., 74, 613; A., 1114. 8 8 Ibid., p. 619; A., 1114252 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.possible linkings just mentioned, other than that present in thepneumococcus acid, is responsible for this isomerism.The parent polysaccharides from which these interesting sugaracids are derived are regarded as bei,ng composed of units of thealdobionic acid in the case of the pneumococcus substance, and ofunits composed of two molecules of the aldobionic acid and onemolecule of glucose in the case of the Friedlander substance.To the list of organisms which yield specific carbohydrates withimmunological properties is to be added the cholera vibri0.3~Organic Phosphates and Lactacidogen.During the past year much attention has been directed to thechemistry of the known hexosephosphates and to the question ofthe presence and functions of organic phosphates in muscle tissue.The most noteworthy advances have been made in the chemistryof the first discovered hexosephosphate, the diphosphate of yeastfermentation, in the chemistry of lactacidogen, the hexosephosphateof muscle, and in the demonstration that there are present in musclecertain organic nitrogenous phosphates which appear to play ahighly important r6le in muscle function.The Hexosediphosphoric Acid of Yeast Fermentation.-Morgan 40has been able to prepare from this acid the a- and p-methylhexoside-diphosphoric acids by subjecting the parent substance to theFischer-Speyer acid-methyl alcohol process.The two stereoiso-merides were obtained in the form of their brucine and barium salts.The glucosidic methyl group of the a-acid is more readily removedby hydrolysis than that of the p-acid, but neither hexoside ishydrolysed by emulsin. On the other hand, invertase causes apartial removal of the methyl group of the a-acid, but it does notaffect the p-acid. Of great interest is the observation that the boneenzyme (phosphatase) rapidly removes the phosphoric acid groupsof the p-acid, leaving a strongly laevorotatory, non-reducing sub-stance possessing the properties of a methylfructoside. An extensionof these results recently described by Morgan and Robison41 hasled to the suggestion that the structure of hexosediphosphoric acidis that of y-fructose-1 : 6-diphosphoric acid :H H TH YHs9 Landsteiner and Levine, J.E x p . Med., 1927, 46, 213.40 Biochem. J . , 1927, 21, 675; A., 749.41 Report of the Meeting of the Biochemical Society (Dec. 9th), J. Soc.Chern. Ind., 1927, 46, 1183BIOCHEMISTRY. 253By the action of bone phosphatase on the a- and p-methylhexosidedi-phosphoric acids, the corresponding a- and p-methylhexosides wereobtained, and these underwent rapid hydrolysis at room tem-perature on being treated with 0-O1N-hydrochloric acid to yield alaevorotatory sugar corresponding to +fructose. Such behavioura t once suggests one of the "reactive" butylene-oxidic types ofsugar and this was confirmed by converting the 8-methylhexosideby methylat ion into the corresponding tetramet hyl p -me t hyl-hexoside.The latter had [a]i2, - 64", and on hydrolysis yieldedan ap-tetramethyl hexose having [a]:$, + 30" in close agreementwith the known rotation of ap-tetramethyl y-fructose, and widelydivergent from that of the corresponding normal (amylene-oxidic)ap-tetramethyl fructose, which has [.ID - 142". Morgan andRobison seem justified in inferring that the existence of theunstable butylene-oxidic ring in conjunction with an unsubstitutedreducing group makes it very probable that the second phosphoricacid group occupies position 6, although it is obvious that the proofis not absolute.This result should not be regarded as unexpectedin view of the known fact that all hitherto described naturallyoccurring compounds of fructose have been shown to exist in they- or butylene-oxidic form, so that hexosediphosphoric acid wouldappear to fall into line with other fructose compounds. Schlubachand Rauchenberger 42 have recorded the complete methylation ofhexosediphosphoric acid via the silver salt, which on treatmentwith methyl iodide yielded tetramethyl hexosediphosphate, andon further treatment with silver oxide and methyl iodide affordedtetramethyl trimethylhexosediphosphate, which is reported to have[.ID + 20-77" in chloroform solution. It would be of great interestto know if the latter were susceptible to the action of any phos-phatase preparation.The Hexosernonophosphoric Acid of Yeast Fermentation.-Neubergand Leibowitz 43 have made a study of the hexosemonophosphoricacid first isolated from yeast fermentations by Robison.They arriveat the conclusion that the discrepancies between the reducing powerafter hydrolysis of the ester with taka-diastase, as determined bycopper (Bertrand) and by hypoiodite (Willstatter-Schudel) methods,cannot be explained, in view of the polarimetric findings, by assum-ing the presence of a mixture of 85% of glucose with 15% of fructose.The hexosemonophosphoric acid is thought to consist of from 80 to90 yo of a homogeneous substance which suffers secondary changesin the sugar residue on being hydrolysed. Meyerhof and Loh-r n a n ~ ~ , ~ ~ also employing the method of Willstiitter and Schudel,44 Ibid., 1927,185, 13; A,, 697,42 Ber., 1927, 60, 1178; A., 644.A3 Biochem, Z., 1927, 184, 489; A,, 700254 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.conclude that Robison’s monophosphate has a higher aldose valuethan Neuberg’s, a result which is not surprising in view of Morganand Robison’s investigations of the yeast diphosphoric acid fromwhich Neuberg’s acid is derived.In a further publication, Neubergand Leibowitz 45 record the conversion of hexosediphosphoric acidof yeast into Neuberg’s monophosphate by the action of taka-diastase, and of Robison’s monophosphate into the diphosphate bythe action of bottom yeasts. This is the first record of the prepar-ation of the Neuberg monophosphate by strictly biological methods,and the conversion of Robison’s monophosphate into the typicalyeast diphosphate probably involves, according to our presentconception of the relationship of these two compounds, the pre-liminary removal of the phosphoric acid group.Euler and Myr-back 46 also state that when Robison’s hexosemonophosphate istreated with dried bottom yeast, one half is fermented and theother half is converted into the diphosphate.An interesting point in the biochemistry of the carbohydrates,involving the behaviour of sugar phosphates, has been raised byProfessor R0binson.4~ He points out that in the hydrolysis ofphosphoric esters there is much evidence to suggest that, if theoxygen atom be directly attached to an asymmetric carbon atom,optical inversion should in many cases be observed.It has alwaysbeen difficult to explain the formation of glucose from galactose,or the reverse change, without assuming a profound disruption ofthe carbohydrate molecule. Professor Robinson now suggests thatthe galactose configuration may be derived from that of a glucose-4-phosphoric acid by a dephosphorylation involving a, Waldeninversion. This hypothesis is highly suggestive in view of the wide-spread occurrence of sugar phosphates in nature. It is to be notedthat it would be excluded if glucose possessed a butylene-oxidicstructure. Levene 4* has criticised this hypothesis unfavourably inpointing out that the acid hydrolysis of glucose-3-phosphoric acid isnot accompanied by any optical inversion, but the original theorypresumably did not regard every or any method of hydrolysis asnecessarily involving the inversion.Professor Robinson has alsosuggested that the pentose of plant nucleic acid, which is isolatedin the form of the rare sugar d-ribose, may in situ be the muchcommoner d-xylose, the removal of the phosphoric acid group fromthe latter during hydrolysis inverting the codguration of (neces-sarily) the 3-carbon atom. This view also is criticised by Levene.4 5 Biochem. Z., 1927,187, 481; A., 993.46 Z. phpiol. Chem., 1927, 167, 236; A., 794.4 7 Nature, 1927, 120, 44; A., 960.4 8 Ibid., 1927, 120, 621; A., 1226BIOCHEMISTaY. 255Lactacidogen.-During the period covered by this Report thechemistry of lactacidogen has undergone a modification which willprobably re - orient many investigations of the chemical mechanismsunderlying muscle contraction.Embden and Zimmermann 49 in1924 identified muscle lactacidogen with the hexosediphosphoricacid of yeast fermentation, since the two substances were shown toform the same neutral brucine salt. The method of isolation oflactacidogen which these investigators used a t that time involvedthe treatment of the muscle press-juice with glycogen, sodiumfluoride, and sodium bicarbonate, with the view of removing, by aprocess of fermentative re-synthesis, the free phosphate present inthe press-juice. It was thought that this synthetic processinvolved merely the re-formation of lactacidogen which had suffereddegradation during the extractive manipulations.That thisprocedure yields a hexosediphosphoric acid identical with thatproduced during yeast fermentation has recently been confirmedby Pryde and Waters,5o who obtained a brucine hexosediphosphatefrom rabbit's muscle with a specific rotation, [a]:& - 30*7",identical with that of a carefully purified preparation of the brucinesalt of the yeast acid. During the past year Embden and Zimmer-mann 51 have isolated lactacidogen from rabbit's muscle by amodified process which omits the fermentative re-synthesis usingglycogen and fluoride, and they have obtained, instead of hexose-diphosphoric acid, a hexosemonophosphoric acid-an observationwhich has also been confirmed by Pryde and Waters.52 Embdenand Zimmermann state that the new monophosphate differs fromthe two previously known natural monophosphates (Robison's andNeuberg's), but Pryde and Waters have encountered anomalies inthe rotation and solubility of their various preparations which leadthem to suspect the homogeneity of the monophosphate obtainedby them. Embden and Zimmermann have shown that the newmuscle monophosphate is converted by muscle press-juice into lacticacid, and by muscle press-juice, glycogen, and fluoride, into hexose-diphosphoric acid.They are therefore disposed to identify lact-acidogen with the new monophosphate. In the absence of theartificial re-syn thesising solutions, neither Embden and Zimmer-mann nor Pryde and Waters were able to detect the presence ofany diphosphoric acid. It is none the less possible that thetemporary formation of the diphosphate may play some part inthe muscle process (compare p.261).49 Ann. Repow, 1925, 22, 224.6o Report of the Meeting of the Biochemical Society (Dec. 9th), J . SOC.O1 2. physiol. Chena., 1927,167, 114; A., 749.Chem. Ind., 1927, 46, 1182.s2 LOC. cit256 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Adenylic Acid.1n the course of the extraction of the mono-phosphoric acid from rabbit's muscle, Embden and Zimmermann 53encountered a nitrogenous organic phosphate which they were ableto identify as adenylic acid-an observation which again has beenconfirmed by Pryde and Waters.54 It would appear highly probablethat adenylic acid is the parent substance of inosinic acid, longknown to be a constituent of muscle extractives, since a simpleprocess of deaminisation of the former would yield the latter.That such a process, involving release of nitrogen, may play somepart in the contractile mechanism is suggested by a growing bodyof evidence, which will be considered shortly.Meanwhile mentionmust be made of another nitrogenous organic phosphate for whicha place will probably have to be provided in muscle chemistry.Phosphugen.-Eggleton and Eggleton, 55 in determining theinorganic phosphate of muscle, found that methods such as thoseof Briggs or Embden, in which acid reagen$s are used, gave results,on the resting gastrocnemius of the frog, which were higher, bysome 70 mg.P per 100 g. of muscle, than the results obtained by amethod such as the Bell-Doisy, which is carried out in a mildlyalkaline solution and gave results of the order 20 to 25 mg. P per100 g. of tissue. They found that the discrepancy was due to thepresence in the muscle of a labile organic phosphate which wasrapidly broken down in acid solution to form inorganic phosphate.In a further study 56 it was shown that this labile organic phosphateparticipates in the chemical mechanism of contraction and is com-pletely broken down when the muscle is fatigued in tetanus. Norestitution of the organic phosphate was observed under anaerobicconditions, but in the presence of oxygen it is rapidly re-formed andan equivalent amount of inorganic phosphate is lost.This Grobicrestitution process is apparently more rapid than the removal oflactic acid which occurs during the recovery phase. Eggleton andEggleton suggested the name " phosphagen " for this unknownlabile phosphoric acid compound. Fiske and Subbarow 57 inAmerica encountered the same labile phosphorus compound andshowed that in the normal resting voluntary muscle of the cat,what had previously been regarded as " inorganic phosphate "consisted of some 60 to 75 mg. of labile organic phosphate and some20 to 25 mg. of true inorganic phosphate per 100 g. of tissue, figureswhich are remarkably close to those of Eggleton and Eggleton forthe frog. Fiske and Subbarow also made the highly interestingb3 2. physiol. Chern., 1927, 167, 137; A., 787.64 L O G . cit.5 6 Biochem. J . , 1927, 21, 190; A,, 271.b6 Eggleton and Eggleton, J . Physiol., 1927, 63, 155; A., 990.Science, 1927, 65, 401 ; A., 990BIOCHEMISTRY. 257observation that the labile phosphorus compound was composed ofcreatine and phosphoric acid, an observation which was shortlyafterwards confirmed by Eggleton and E g g l e t ~ n , ~ ~ one molecule ofcreatine being associated with each atom of phosphorus.These observations are obviously of the greatest importance inrelation to all previous determinations of the inorganic phosphoricacid of muscle, and a further point of interest emerges when it isseen that incubation of a chopped muscle in the presence of sodiumfluoride leads to the conversion of “ phosphagen ” into an acid-stable organic phosphate.It would appear possible that ‘‘ phos-phagen ” is the source of the second phosphoric acid residue whichis added on to Embden and Zimmermann’s muscle hexosemono-phosphate when the latter is treated with muscle press-juice,glycogen, and fluoride. The part played by “ phosphagen ” in thecontractile process is not yet clear. That most, or probably all, ofthe muscle creatine is present in the resting muscle in combination,with phosphoric acid is strongly suggested by the fact that creatine,like “ phosphagen,” is most abundant in voluntary muscle, less soin cardiac muscle, and present only in traces in involuntary muscle.Ammonia Formation i n Muscle.In the Report for last year the observations of Hoet and Marks 59on the precipitate rigor, which sets in immediately after death froman overdosage of insulin or from excessive thyroid feeding, in whichconditions the muscles contain no glycogen, little or no lactacidogen,and show no accumulation of lactic acid, suggested that a possibledetermining factor in this type of rigor was an alkaline phase.Atthe time little or nothing was known of any possible source ofalkalinity, but since then it has been shown that the formation ofammonia is probably an integral part of the muscle process, andthis suggestion gains strength in view of the occurrence in muscleof the nitrogenous compounds which we have just considered.Parnas and Mozolowski 6o have shown that the maceration ofvertebrate muscle in water or saline leads to the formation of about5 mg.of ammonia per 100 g. of muscle. This formation of ammoniais inhibited by a borate buffer of pH 9.3. It is suggestive that thistraumatic formation of ammonia is most marked in voluntarymuscle, less so in heart and smooth muscle, and absent in glandulartissues. The process of formation is a rapid one, being complete inthe case of the frog’s gastrocnemius in 90 seconds. On extractingmuscle with a borate solution the ammonia precursor is obtainedJ . SOC. Chem. Ind., 1927, 46, 485.68 Ann. Reports, 1926, 23, 242.6o Biochem. Z . , 1927, 184, 399; A., 694.REP.-VOL. XXIV. 268 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.together with an enzyme which acts upon it, and ammonia formationoccurs on simple neutralisation of this extract, although a t a muchslower rate than in the intact cellular tissue.The precursor isstable in both acid and alkaline solutions. Since the ammonia ofthe intact muscle is increased by electrical stimulation and bystrychnine convulsions, it is inferred that its release is definitelyrelated to contraction. Habs,61 in association with Embden, alsohas studied the occurrence of ammonia in muscle, and shows thatits formation in muscle pulp runs parallel with the liberation of freephosphate. It is an attractive hypothesis to regard adenylic acidas the precursor of the muscle ammonia, and Embden 62 has indeedadvanced this suggestion, but Parnas points out that there wouldbe required for the traumatic formation of 5 mg.yo of ammonia25 mg. % of purine nitrogen as adenylic acid. Now the total purinenitrogen of the frog's muscle, including that of nuclear substances,is only 35 mg. yo. For the muscles of other animals, too, almostthe whole of the purine nitrogen would have to be present in theform of adenylic acid should this substance be the sole precursor ofthe ammonia determined by Parnas and Mozolowski. It is difficultto see how creatine can be regarded as the ammonia precursor, noris there any evidence to suggest that it is. As Habs points out,adenylic acid is the only substance capable of forming ammonia sofar detected in the muscle and as such it merits further consideration.In a comparison of the chemical processes of " trained '' (subjectedto short, periodic, daily faradisation in the intact animal) as com-pared with " untrained " muscle, Embden and Habs 63 show thatthe " trained '' muscle shows a marked increase in glycogen contentand a small but definite increase in the residual nitrogen.They donot suggest what particular nitrogen compound or compounds areincreased, but do show that the creatine figures are not affected.It is obviously difficult a t the moment to correlate this newerwork on the chemistry of muscle with the older work on lactic acidformation, but it seems certain that a considerable widening of ourviews on the whole subject must soon result.Lactic Acid-forming Enzymes from Muscle.Much interesting work has been published on the processes oflactic acid formation in muscle, but in the opinion of the Reporterthe most significant advance is the isolation by Meyerhof of anactive lactic acid-forming enzyme from muscle.This was referredto in the Report of last year,64 but since that date Meyerhof has61 2. physiol. Chern., 1927, 171, 40.s2 Klin. Wochenschr., 1927, 6, 628.e8 2. phy8iol. Chem., 1927, 171, 16.64 Ann. Reports, 1926, 23, 242BIOCHEMISTRY. 269himself provided a useful summary,65 and many more recent resultshave been published which justify a detailed account in the presentyear's Report.Meyerhof 66 has shown that it is possible to separate completelythe lactic acid ferment from frog or rabbit muscle and to obtain it inaqueous solution free from the carbohydrates of the muscle. Follow-ing a method of Buchner, it is possible, by precipitation with acetone,to obtain a dry enzyme preparation which, when redissolved,possesses 40% of the activity of the original extract.For example,when glycogen is added to it, the enzyme preparation shows forseveral hours an activity about as great as that of the mincedmuscle a t the same temperature, when calculated against muscleweight. Calculated against the dry weight of the extract, itsactivity is a t least five times as great as that of the muscle pulp.A co-enzyme, which is dialysable and thermostable, can be separatedfrom the enzyme mixture. It has been shown that this water-soluble lactic acid ferment splits hexoses only under special con-ditions, which will be referred to later, but on the other hand, in thepresence of inorganic phosphate 67 it readily acts upon starch,glycogen, the starch components amylose and amylopectin, and thesimpler compounds derived from them, such as tri- and di-hexosans,splitting them all to lactic acid with about the same velocity.During hydrolysis of the polysaccharides, a phosphoric esteraccumulates a t first quickly, then more slowly, and this ester canbe completely decomposed into lactic acid and phosphate by warminga t 37".The muscle enzyme also acts, but rather more slowly,upon the hexosediphosphoric acid of yeast. It would, however,appear that different enzymes are concerned in these reactions.For instance, it is easy to separate from the enzyme complex theenzyme which attacks hexosediphosphoric acid.Heating a t 37 Ofor 15 minutes destroys the capacity of the extract to split glycogenand other polysaccharides, but scarcely affects its capacity to splitthe hexosediphosphoric acid to lactic acid. Removal of the co-ferment by dialysis also yields an enzyme solution which stillsplits hexosediphosphoric acid, but which is without action onglycogen or starch. This varying behaviour towards glycogen andhexosediphosphoric acid depends upon the fact that brief heatingat 37", or removal of the co-ferment, destroys the ability of theenzyme extract to esterify the cleavage products of the poly-saccharide with inorganic phosphate. Thus the labile hexose firstformed by the cleavage of the glycogen must first be esterified with6 5 J .Gen. Physiol., 1927, 8, 631.6 6 Biochem. Z., 1926, 178, 395, 462; A., 1927, 75.G 7 Mcyer, ibid., 1927, 183, 216; A., 6902f3) ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.phosphoric acid before splitting and lactic acid formation can occur.This is well illustrated by the delayed appearance of lactic acidwhen the muscle enzyme preparation acts upon glycogen or starch,as compared with its immediate appearance when the substrate ishexosediphosphoric acid.Meyerhof’s muscle enzyme, even in the presence of the co-enzyme, acts but slowly on the fermentable hexoses,68 but byextracting baker’s yeast with water and precipitating the extractwith alcohol, there is obtained a substance which, when added to themuscle extract, greatly accelerates the rate of formation of lacticacid from hexoses.In neutral solution a t O”, this activator can bepreserved indefinitely, but it is readily destroyed by heat and byacids and alkalis. Treatment of a h.exose with muscle extract inthe presence of the activator leads to a rapid formation of lactic acidand a, parallel disappearance of inorganic phosphate. At the pointwhen all the inorganic phosphate has been used up, the velocity offormation of lactic acid falls rapidly and subsequently runs parallelto the liberation of inorganic phosphate, that is to say, in thesecond stage lactic acid and phosphate are being formed in equi-molar proportion. If at the end of the first stage a further additionof inorganic phosphate be made, the original velocity of lactic acidformation is restored.Meyerhof and Lohmann 69 have investigated the action of themuscle extract on the hexosemonophosphates obtained from naturalsources, and upon certain synthetic hexosemonophosphates.It isan interesting fact that the muscle extract is almost without actionon the synthetic monophosphates, whereas the natural mono-phosphates undergo a transformation similar to that of the poly-saccharides, hexosediphosphoric acid, and the fermentable hexoses,there being a rapid formation of lactic acid and a disappearance ofinorganic phosphate, followed by a slower production of lactic acidrunning parallel with the reappearance of inorganic phosphate. Inthe case of the monophosphates, as with the polysaccharides, thepresence in the muscle extract of the co-ferment is necessary.Meyerhof and Meyer 70 have described a method of purifying thelactic acid enzyme of muscle and a final preparation is obtained, afteradsorption on aluminium hydroxide made according to Willstatter’smethod, which is capable of forming 1.0 to 1.5 mg.of lactic acid ineach hour per mg. of protein present in the purified enzyme extract.Since in this process of purification the co-enzyme is removed, boiledmuscle juice must be added before any action on polysaccharides and6 8 Biochem. Z., 1927, 183, 176; A,, 590.Ibid., 185, 113; A,, 697.70 J . Physiol., 1927, 64, XVI; A., 1112BIOCHEMISTRY. 261hexosemonophosphates is observed. Meyerhof and Meyer alsostate that in addition to enzyme and co-enzyme a hydrolysableester is necessary and that the latter can be recovered from thebaryta precipitate of fresh muscle extract or boiled juice.Thissubstance is not Embden’s lactacidogen (monophosphate), but isstated to be an ester which behaves as a diphosphoric ester. Itsr6le would therefore appear to correspond to that of hexose-diphosphoric acid in inducing alcoholic fermentation in yeast juice.These results, which have been described in some detail in viewof their importance, show many striking similarities to the processesof yeast fermentation and would appear strongly to suggest thatboth hexosemonophosphates and hexosediphosphates are inter-mediate stages in the enzymic degradation of carbohydrate both bymuscle extract and by yeast. In regard to this question it isinteresting to note that Harden and Henley 71 have re-examinedthe data upon which the equation of alcoholic fermentation wasoriginally based.They now find that the ratio CO,/total P esterifiedis on the average 0-9, indicating that about 10% of the phosphorusis esterified without equivalent evolution of carbon dioxide. Theysuggest that the product of this esterification is probably a mono-phosphate. The ratio CO,/diphosphate is on the average 2.38,but varies considerably in individual cases. The fact that it isalways somewhat greater than 2, as required by the original equationof Harden and Young, suggests that the diphosphate is originallyproduced in accordance with the equation, but that a portion of thisis subsequently hydrolysed with the formation of a monophosphate.Insdin and its R61e in Carbohydrate Metabolism.Crystalline Insulin.-In the Report of last year mention was madeof the claims of Punk and of Abel regarding the isolation of insulinin a pure state.72 During the past year both these workers havemade further publications of great interest.Abel and hisassociates 73 state that when pyridine is added to an acid solutionof insulin, containing brucine acetate in amount sufficient to bringthe pH to 5.55-5.65, the insulin separates in a crystalline condition.On applying this method to the purification of commercial insulinthere was obtained, by working up the pyridine precipitate and themother-liquors, 0.4548 g. of crystalline insulin from 2.001 g.of thecommercial insulin powder. Abel has naturally coxsidered thepossibility that the crystals obtained are not really insulin but thoseof an inactive compound containing a very small quantity of highly71 Biochem. J . , 1927, 21, 1216; A., 1113.72 Ann. Reports, 1926, 23, 238.73 Abel, Geiling, Rouiller, Bell, and Wintersteiner, J . Pham. Exp. Ther.,1927, 31, 66; A., 701262 ANNUAL REPORTS ON THE PROQRESS OF CHEMISTRY.active material adsorbed on their surfaces. This possibility isdismissed on what appears to be convincing evidence. Crystallineinsulin has an activity exceeding 40 international units per mg.,and it gives the biuret, Pauly, Millon, and ninhydrin reactions,Tryptophan is said to be absent. The simplest formula correspond-ing to the analyses is C4,H,,0,4NllS,3H,0, which should becompared with the earlier alternative suggestions of Funk,C69H1,2022Nl,S and C,,H, 14024N2,S.Crystallographic observ-ations suggest that insulin is dimorphous. This observation is ofinterest in view of Funk’s most recent claims.74 Funk states thatinsulin may be fractionated to yield insulin-A and insulin-B. Theformer, which is present in larger proportion, decreases the bloodsugar of normal rabbits and of those having high initial blood sugars.On the other hand insulin-B is said to increase the blood sugar andto cause dilution of the blood with large retention of water. DuVigneaud T 5 has recently published observations which corroboratein large measure the statements of Abel. For example, he has beenable to obtain a highly active crystalline preparation of insulin byfollowing the method of Abel.Du Vigneaud’s preparation con-tains labile sulphur which he states is present in a disulphide form.He regards insulin as most probably a derivative of cystine and pointsout that the behaviour of the sulphur in insulin is quite parallel tothat of the sulphur in amino-acid derivatives of cystine. It issuggested, in view of the probable presence of a disulphide grouping,that Abel’s formula should be doubled. On the basis of theseresults, it now appears highly probable that sulphur is an integralpart of the insulin molecule, a suggestion first made by Dudley 76in 1923, when he formed the impression that insulin was a complexprotein derivative.The R6Ze of Insulin.-Thaniihauser and Jenke ,7 recently reportedthat glucosone, the keto-aldehyde derivative common to glucose,mannose, and fructose, was utilised by diabetics.Hynd 78 nowreports that, unlike dihydroxyacetone, which is also utilised bydiabetics (but compare p. 263) and readily alleviates the hypo-glyczmic symptoms, glucosone produces no alleviation. On thecontrary, when it is injected into mice a condition is produced similarto that following insulin injection, resulting in convulsions, coma,and death. Lactosone and maltosone, the corresponding keto-aldehydes derived from lactose and maltose, are quite negative in74 Science, 1927, 65, 39; A., 594.7 5 J . Biol. Chem., 1927, 75, 393.78 Ann. Repow, 1923, 20, 178.7 7 Arch.exp. Path. Pharm., 1926, 110, 500; A., 1926, 317.Proc. Roy. Soc., 1927, B, 101, 244 ; A., 480BIOCHEMISTRY. 263their actions. The glucosone effect, like that produced by insulin, isslightly modified by administration of glucose, and appreciably SOby adrenaline and pituitrin. Despite the similarity between theactions of insulin and glucosone, the latter does not lower the bloodsugar; on the other hand, increases of from 0.16 to 0*24% havebeen observed in mice. Hynd interprets these observations bysuggesting that insulin is an oxidase which catalyses the conversionof glucose into glucosone, that glucosone is an obligate first step inthe oxidation of glucose, and that therefore utilisation of glucose isdiminished or lacking if insulin be deficient or absent, as it wouldbe in the blood of pancreatic diabetics.Should the concentrationof glucosone become too high, owing to excessive insulin adminis-tration, convulsions would occur just as they do when glucosone isinjected directly. On this view the convulsions of insulin hypo-glycamia are not to be ascribed to the lowered blood sugar per se,but to the conversion into glucosone of that part of the sugar whichdisappears and undergoes oxidation. The glucosone symptoms areinhibited by a previous injection, and markedly relieved by asubsequent injection of acetoacetic acid. Glucosone would appearto be functioning here as a ketolytic substance in Shaffer’s sense.These conclusions are in accord with the views of Thannhauser andJenke, since these workers formed the view that the disturbancein the diabetic is due, not to inability to convert glucose afterglycogenolysis into a utilisable form (e.g., y-glucose), but to theinability to convert glucose into glucosone, whicb.is then utilisedfor the synthesis of glycogen or oxidised. It would appear thatglucosone is capable of forming glycogen even more readily than isfructose. Lambie 79 is in essential agreement with the suggestionthat the diabetic primarily lacks the power of transforming glucoseinto some intermediate product which can be oxidised by thediabetic as well as by the normal subject. But in view of the earlierresults of Kermack, Lambie and Slater,so and of Lambie and Red-head,s1 he attaches great importance to dihydroxyacetone as theintermediate product.Markowitz and Campbell 82 have, however,arrived a t diametrically opposite views regarding the utilisabilityof dihydroxyacetone by the diabetic, stating that, when it isadministered to depancreatised dogs, its concentration in the bloodsteadily falls, while the concentration of glucose rises, andultimately the dihydroxyacetone is quantitatively excreted asglucose. They therefore do not regard dihydroxyacetone as an79 J . Sot. Chem. Ind., 1927, 46, 300; A., 989.82 Amer. J . Physiol., 1927, 80, 848, 661; A,, 693.Biochem. J . , 1926, 20, 486; 1927, 21, 40; A., 1926, 861; 1927, 282.Ibid., 1927, 21, 649; A., 693264 ANNUAL REPORTS ON TRE PROGRESS OF CHEMISTRY.intermediate in the catabolism of carbohydrate.It is, in their view,not oxidised and has no anti-ketogenic action.8ynthaZin.-Clinicians have recently devoted some attention to asynthetic preparation called “ synthalin,” which is a decamethylene-diguanidine derivative (om-diguanidyldecane), and was introducedby Frank, Nothmann, and Wagner 83 as a substitute for insulin,but having the advantage over the latter in that it could be giveneffectively by mouth. Simola 84 has published a detailed examin-ation of the physiological action of “synthalin” and finds veryconsiderable differences between the action of the natural hormoneand the artificial substitute. For example, the hypoglyczmia pro-duced by the latter is far less marked, appears only after some hours,and is more lasting than that produced by insulin. In addition toits hypoglycsmic action, “ synthalin,” like insulin, depresses theblood inorganic phosphate, but in an irregular manner.If apoisonous dose be administered, the inorganic phosphate risessharply, reaching twice its normal value after 24 hours. Lacticacid also is increased in the blood after (‘ synthalin ” administration.Toxic symptoms of guanidine poisoning often develop and it wouldappear from clinical experience on the human subject that the toxicnature of the artificial substitute is likely severely to restrict itsuse. There is, however, no doubt that it does produce someincrease of sugar utilisation in the diabetic ; for instance, Lublin 85reports that diabetics, treated with “ synthalin ” by mouth, showan increase in the respiratory quotient following the administrationof glucose.During the past year two studies have been published on theaction of galegine.Galegine is a guanidine derivative shown byBarger and White 86 to have the constitution :Simmonet and Tanret 87 have shown that subcutaneous injection ofgalegine sulphate in rabbits produces in most cases hypoglyczmia,but in some cases the condition is preceded or replaced by hyper-glycamia. The effect is very similar to that of insulin and may berelieved somewhat by an injection of glucose. Miiller and Rein-wein88 have published very similar findings. They state that,as Deut. med. Wochenschr., 1926, 52, 2067.EP 2. physiol. Chern., 1927, 168, 274; A., 900.85 Arch.exp. Path. Phawn., 1927, 124, 118; A., 896.86 Biochem. J . , 1923, 17, 827; A., 1924, i, 272.81 Compt. rend., 1927, 184, 1600; Bull. SOC. chim. biol., 1927, 9, 908;88 Arch. exp. Path. Pham., 1927, 125, 212; A., 1109.A., 991BIOCHEMISTRY. 265when administered to rabbits or when given in large doses to dogs,it raises the blood-sugar. When it is given in small doses to dogs,the blood-sugar is lowered, and in the case of depancreatised dogsboth blood and urinary sugars are lowered. The hyperglycaemicaction is antagonised by ergotamine, andwhen the two substances areadministered together hypoglycemic convulsions may be producedin both rabbit and dog.Hcemogtobin, Hcemochromogen, and Cytochrome.Although the subject of haemoglobin has been dealt with byProfessor Drummond in the Annual Reports for the two precedingyears,sg the many important advances in the study of this respiratorypigment and related substances have, until very recently, proveddifficult to correlate with one another, and it is felt that a surveyof the developments of the past two or three years is called for in thepresent Report. The Reporter is encouraged in undertaking thistask in virtue of a very helpful summary of the present positionpublished by KeiIin.goThe complex substituted tetrapyrrole compounds called porphyrinsform the basis of the respiratory pigments which we shall considerin the present section of this Report. A large series of porphyrinsof animal and vegetable origin is known, and some, notably aetio-porphyrin, have been synthesised.They form characteristiccompounds with metals for which Schummgl has suggested thegeneral name porphyratins. Hzematin or haem, the prostheticgroup of hzemoglobin, which is an iron porphyratin, exists in twoforms, oxyhzematin and reduced hzematin, the latter being thehzm of Anson and M i r ~ k y . ~ ~ These two hzematins, differing intheir state of oxidation, also differ in solubility, colour, absorptionspectrum, and gas-combining power. Furthermore, characteristicdifferences are shown by the two haematins according as they arepresent in alkaline, neutral, or acid solution. The differences in theabsorption spectra are slight in the case of reduced haematin underthese varying conditions of reaction, but, on the other hand, markeddifferences are shown by oxyhamatin under the same conditions.An important advance in the study of the relationship of these iron-porphyrin compounds to hzemoglobin and related pigments wasrendered possible by Hill and Holden93 when, in 1926, they suc-ceeded in separating from hzemoglobin the natural globin withwhich the prosthetic group is associated, and they were able to show89 Ann.Reports, 1925, 22, 237; 1926, 23, 249.@O SOC. Biol., Rdunion PldniBre, May 1927 (Reprint).91 2. physiol. Chem., 1926, 152, 147; A,, 1926, 537.O2 Ann. Reports, 1925, 22, 237.93 Biochem. J . , 1926, 20, 1326; A., 1927, 67.I 266 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.that their natural globin combined with neutral oxyhaematin, overthe range pE 5 to 10, to yield methaemoglobin.Since methzemo-globin may be readily converted into reduced haemoglobin and sincethe latter, shaken with air, forms oxyhaemoglobin, the naturalrespiratory pigment may be synthesised in this way from its com-ponents. If in place of oxyhaematin reduced haematin (i.e., haem)be used, it also combines with natural globin (at pPH 9.0) to yieldreduced haemoglobin directly. Hill and Holden were able to showthat natural globin may also combine with porphyrins other thmthat of hEmoglobin, and even with porphyrins containing, not iron,but other metals such as manganese, cobalt, nickel, copper, zinc,and tin. The absorption bands of the compounds so obtained allshow a displacement towards the blue end of the spectrum whencompared with the bands of haemoglobin.Furthermore, naturalproteins other than globin do not combine with oxyhaematin or withreduced haematin to give compounds comparable with those of thehaemoglobin series. The only known example of a natural pig-ment parallel to haemoglobin is Munro Fox’s chlorocr~orin.~~ Inthis pigment the prosthetic group contains iron, but the porphyrindiffers from that of haemoglobin. Neutral oxyhaematin combineswith a number of nitrogenous derivatives, including denaturedglobin, nicotine, pyridine, and histidine, to give a series of com-pounds which Keilin has called parahaernatin~.~5 It would appearthat helicorubin, the pigment found in the liver and gut of pul-monate molluscs and in the liver of the crayfish, belongs to thisgroup of substances.Alkaline oxyhaematin does not combine withnitrogenous substances.Hcemochrornogen.-A highly important group of compounds isencountered when we consider those substances formed by reducedhaematin interacting with nitrogenous compounds. We havealready seen that when the nitrogenous substance is natural globin,reduced haemoglobin is obtained, but with denatured globin a sub-stance of a much lower degree of molecular complexity, namelyhzemochromogen, results. Many other nitrogenous compounds inaddition to globin may enter into combination with reducedhaematin : amongst them are to be numbered other proteins suchas denatured albumin and globulin, glycine, nicotine, pyridine,piperidine, hydrazine, and ammonia.We owe to Anson andMirsky 96 the general conceptions of the relationships of these com-pounds to haemoglobin, and of the molecular structure of thehzemochromogens. The latter all differ markedly from reduced94 Proc. Roy. Soc., 1926, B, 99, 199; A., 1926, 313.95 Ibid., 1926, B, 100, 129; A,, 1926, 857.me Ann. Reporb, 1925, 22, 237BIOCHEMISTRY. 267haematin in solubility, colour, absorption spectrum , and in the com-pounds which they form with carbon monoxide. The haemo-chromogens oxidise readily in the air, and in an alkaline mediumthey dissociate into their nitrogen compound and haematin, or, asAnson and Mirsky called it, haem. Keilin has shown that in aneutral solution they do not dissociate but are transformed intoparahzmatins, which we have seen to be compounds of oxyhaematin.Until the work of Anson and =sky was published, generalacceptance was accorded t o the idea that what were then calledhaematin and haemochromogen comprised the protein-free pros-thetic group of hzemoglobin in an oxidised and a reduced conditionrespectively.Anson and Mirsky, in the work which has just beenoutlined above, clearly established the true nature of hzemochrom-ogen as a compound of globin (or, in the case of artificial hzemo-chromogens, of some other nitrogenous substance), but they weremistaken in stating that haematin was also a globin compound.It was for these reasons, one correct, the other a mistake, that theterm hem was introduced by them to designate the free pros-thetic compound, and a good deal of confusion has since resulted.A&.HCI+OsL-- ReducedAlk. reduction ,7 hsmatin (hsm) HsIlliIl Alkaline A-oxyhamatin - 7Neutral z oxyhsmatindd \‘Acid HsmochromogenReduced hzmoglobin MethEmoglobinScheme showing relationship of the blood pigments. The expressions + N and- N are intended to indicate the addition or the removal of denatured globin orother nitrogenous compound.7reduc268 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.The reader will, however, find the position quite clear if he bears inmind the identity of Anson and Mirsky’s hem with reduced hzm-atin. The cause of the original mistake was cleared up by Keilinwhen he showed that the alkaline hzematins prepared from hzemo-globin and from hzemin crystals were identical and devoid of protein,whereas acid haematin prepared from haemoglobin is a colloidalsuspension of hzematin, which is not united with globin, but isprotected by the latter from precipitation.There is appended ascheme, modified slightly from one given by Keilin, which will befound helpful in tracing the relationships which we have discussed.The term hzemochromogen in its modern usage is really a verywide one, since one may vary, not only the nitrogenous compound,but also the iron-porphyrin. It has been shown that only slightalterations in the characterist,ic absorption bands are producedwhen reduced haematin is combined with a series of nitrogen com-pounds, but, on the other hand, more marked differences resultwhen the same nitrogen compound is combined with differentporphyrins.Another factor which influences greatly the positionsof the bands is the degree of dispersion of the hzemochromogen;with increasing molecular aggregation the bands become displacedtowards the red end of the spectrum. Thus when a haemochromogenis present both in solution and in a fine colloidal suspension, theliquid shows three absorption bands, formed of two superimposedspectra, comprising two a-bands and one fused p-band.Cytochrome.-In 1925 Keilin 97 showed that a very large numberof aerobic plant and animal tissues when examined with a micro-spectroscope showed a series of bands similar to those of thehzemochromogens, and he established the origin of these bands asbeing due to a widespread respiratory pigment which he calledcytochrome.These observations were confirmed and extended bySchumm 98 and by Euler, Fink and Hell~trOm.9~ It became clearthat cytochrome was in fact a porphyratin combined with a nitro-genous substance and showed a remarkable similarity to haemo-chromogen. Keilin has shown that in reality cytochrome is amixture of three haemochromogens, or rather of the same haemo-chromogen in three different physical states, each one of whichcontributes its characteristic a- and p-bands to the complex four-band spectrum of the complete substance, bands a, b, and c beingthe three separate a-bands, and band d the three fused p-bands.Under certain conditions these three hzmochromogens may become9 7 Ann.Reports, 1925, 22, 258.98 2. physiol. Chem., loc. cit. and p. 55; 1926, 154, 171, 314; 1927, 166, 1;99 Ibid., 1927, 169, 10; A., 993.A., 685BIOCHEMISTRY. 269oxidised (in which case the bands disappear) or reduced independentlyof one another, so that the particular bands shown by cytochromeand also their relative intensities may vary with the conditionsemployed. There is also present in all cells which contain cyto-chrome free haematin, and the latter, combining under variousconditions of oxidation and reduction with different nitrogen com-pounds, gives rise to the three haemochromogen components ofcytochrome, two differing in degree of dispersion and the thirdpartly modified by the active process of oxidation and reduction.The respiratory functions of cytochrome have been carefullystudied by Keilin.The fact that the pigment is confined to aErobicorganisms, and its behaviour in them, at once suggested that it isconcerned with the utilisation of oxygen, either directly or inconjunction with an oxydase system. It has been shown that alongwith cytochrome there is found an oxydase which can be detectedby its capacity to form indophenol from dimethyl-p-phenylene-diamine hydrochloride and a-naphthol. It seems probable thatthis oxydase system is identical with the respiratory fermentdescribed by Warburg,2 which is present in yeast and cocci cellsand is inhibited by carbon monoxide. Haldane3 has shown asimilar respiratory system to be present in the wax-moth and incress plants, so that its distribution is probably a very wide one.Keilin has brought forward evidence t o show that cytochrome, orat least two of its component hemochromogens, is oxidised bythis phenoloxydase and reduced by reductases or by other cellularconstituents which become oxidised irreversibly. Cytochrome maytherefore act as a “ Hilfkatalyst ” in the sense of Oppenheimer,*or as a respiratory chromogen acting either as a peroxydase or asa catalyst.It would therefore seem that in cytochrome there isrevealed a considerable part of the complex system of oxidativecellular catalysts.The Porphyrins.-There has been described a very large numberof closely similar porphyrins and their derivatives obtainable fromnatural sources directly or by simple chemical transformations.It would seem probable that the tetrapyrrole compounds fromwhich these are derived must be capable of existing in isomericforms and of giving rise to a large number of simple substitutedderivatives. The most striking recent advance in the study ofthese porphyrins, which fully justifies these suppositions, has been1 Nature, 1927, 119, 670; A., 592.2 Biochern.Z., 1926, 177, 471; 1927, 189, 354; A,, 1926, 1277; 1927,3 Nature, 1927,119, 352; A., 375; Biochern. J . , 1927, 21, 1068; A., 1110.4 ‘‘ Die Fermente und ihro Wirkungen,” Leipzig, 1926.1221270 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.the synthesis of aetioporphyrin, identical with Willstatter’s aetio-porphyrin from natural sources, by Fischer and Klarer,, and ofisoaetioporphyrin by Fischer and Halbigm6 As a result of thisachievement Fischer is able to make a more authoritative suggestionregarding the structure of aetioporphyrin, and therefore of porphyrinsrelated to it, than has hitherto been possible.The suggestedstructure, which forms the basis of these and other porphyrins, isas follows :The structure of aetioporphyrin as demonstrated by synthesis isobtained by substituting for R,, R,, R,, and R, the C,H, radical,and for R,, R,, R,, and R, the CH3 radical. On this basis, currentviews on the constitution of coproporphyrin are expressed bysubstituting for R,, R,, R,, and R, the group -CH,*CH,CO,H,and for R,, R,, R,, and R,, -CH,. The closely related uroporphyrin issimilarly formulated by replacing each of the groups -CH,*CH,*CO,Hin the coproporphyrin formula by the dicarboxylic acid groupIt is clear that from a tetrapyrrole nucleus of this type numerousisomeric and closely related porphyrins can be derived, and it istherefore not surprising that numerous representatives of the classare reported from time to time as occurring in nature. The subjectis still in too complex a state of development t o be suitable forreview, but as illustrative of the type of investigation in progressmay be cited the recent preparation of deuteroporphyrin by Fischerand Ljndner.7 This porphyrin has been obtained by fermentingfresh ox-blood spontaneously, or with yeast, an alkaline reactionbeing preserved throughout. Evidencs is adduced of its constitu-tion and this can be expressed by substituting as follows in theformula already given : for R,, R,, R,, and R,, -CH,, for R, andR,, -H, and for R, and R,, -CH,*CH,CO,H.-CH,*CH( COZH),.Annalen, 1926, 448, 178; A,, 1926, 9G2.Ibid., p. 193; A., 1926, 063.2. physiol, Ci~em., 1926, 161, 27: A,, 1927, 262BIOCHEMISTBY. 271All these porphyrine are capable of forming the correspondingiron porphyratins, and Fischer and his co-workers have preparedsynthetic aetiohamin and isozetiohaemin from the correspondingsynthetic porphyrins by treating the latter with ferric chloride andsodium acetate. The nature of these iron compounds has yet tobe elucidated, but a recent important publication by Hill* givessome indication of their probable nature. Haematoporphyrin wasprepared from pure hzemin and the former was then reconstitutedby artificial means. The corresponding nickel and copper por-phyratins were also prepared. Whereas the nickel and coppercompounds still showed their typical two-band spectra, the ironcompound resembled reduced haematin in showing only an ill-definedregion of absorption. The hzemochromogen type of spectrumshown by compounds of haematoporphyrin with metals other thaniron is shown by Hill not to be due to the presence of nitrogencompounds, and it is suggested that the property of forming haemo-chromogens is limited to the iron-porphyrin compounds. Onaddition of denatured globin, pyridine, or ammonia the iron com-pound gave haemochromogen. Thus the artificial iron-haemato-porphyrin showed the same behaviour as hamin prepared directlyfrom blood. Nickel and copper haematoporphyrins showed nochange on the addition of denatured globin. The iron compoundof hzmatoporphyrin thus behaved exactly as hzmatin and onreduction did not give the haemochromogen spectrum shown byother metallic derivatives of hamatoporphyrin, unless some nitrogencompound was present. It is deduced from these observationsthat haemochromogen is simply the ferrous compound of the por-phyrin, corresponding with the bivalent copper and nickel com-pounds, together with a nitrogenous substance. Since iron hzemato-porphyrin gives a different spectrum according to the reagentspresent when the pigment is reduced in alkaline solution, and sincethis property is not shared by any other porphyratin so far examined,it is inferred that the iron atom alone confers on the pigment theproperty of forming molecular compounds with a large variety ofsubstances when the pigment is in the reduced state.From quantitative measurements of the combination of pyridinewith reduced haematin, Hill has shown that in carbon monoxidehzemochromogen one nitrogen-containing molecule is replaced byCO, there being two such nitrogenous molecules in hzemochromogenitself. By adding the nitrogen compound t o CO-reduced haematin,one molecule of the former is taken up, and by adding excess ofthe nitrogen compound, the CO is displaced by the taking up ofanother molecule of the nitrogen compound and haemochromogen8 Proc, Roy. SQC., 1926, B, 100, 419; A,, 1927, 66272 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.is formed. These changes occur when any nitrogen compound isused which gives a typical haemochromogen, including denaturedglobin itself. Since iron is the only element in combination withthe pigment which causes it to have the property of forming haemo-chromogen, it is simplest to assume that the nitrogen and carbonmonoxide are directly co-ordinated with the iron, which has aco-ordination number of 6. The general formulz for a carbonmonoxide-hsmochromogen and for haemochromogen are thereforewritten thus (Hph being haematoporphyrin and N the nitrogenoussubstance) :HphEFe<N= co HphgFe<NE A'-- and -The chief objection to this view, as Hill himself points out, is thefact that the carbon monoxide compound of reduced hsmatin,without pyridine or other nitrogen compound, contains not twomolecules, but only one molecule of carbon monoxide. The formulacan, however, be written :Hph_FecX, cowhere X is either another molecule of the complex or a moleculeof solvent. It may be added that there is evidence that reducedhsmatin combines with itself to form large molecules in the absenceof the specific reagents mentioned, because of its insolubility andthe slowness with which it reacts with such reagents.C. T. GIMINGHAM.JOHN PRYDE

ISSN:0365-6217    

DOI:10.1039/AR9272400218

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

CRYSTALLOGRAPHY.A REPORT of this nature cannot claim to deal exhaustively withall the work on crystallography, of direct or indirect interest tochemistry, which has appeared during the year. It is necessaryto limit the scope, so as to be able to deal adequately with thesubjects chosen. We have selected for special treatment the workon the influence of atomic size and chemical constitution on thestructure of crystals, which has been so admirably summarised inthe papers of V. M. Goldschmidt, and also the work on the structureof alloys, which, in the hands of Westgren, PhragmBn, and others,has made considerable advances since it was last dealt with in theseReports.Of great interest to all workers on crystallography is the reportby P. P. Ewald and C. Hermann on all crystlal structures in-vestigated by X-ray methods from 1913 to the end of 1926, whichis at present appearing in serial form in the Zeitschrift fur Kristal-lographie.In Vol. 65, which is just completed, the elements and anumber of binary compounds have been dealt with. The descrip-tions of the structures, given in considerable detail, are very clearand extensively illustrated. The whole, when completed, will forma most valuable compendium.Xixes of Ions in a Crystal Lattice.During the last few years a large amount of work has been doneon the sizes of the atomic domains in the crystal state. The ideaof a definite volume associated with a given atom or ion, which,in compounds of the same type, it always occupies, is becomingincreasingly important as an aid to crystal analysis.For an accountof the work which has been done in this subject up to 1926 referencemay be made to the section entitled " Grosse und Bau der Molekiile "by H. G. Grimm in Geiger and Scheel's Handbuch der Physik, XXII,Quite recently a new estimate of ionic radii has been made byL. Pauling,' who bases his work on the idea that the dimensions ofan ion are conditioned by the radius of the outer electron shell, andthat this in its turn, for ions of similar structure, is inversely pro-Proc. Roy. SOC., 1927, [ A ] , 114, 181; A,, 394; J . Amer. Chem. Soc., 1927,49, 765; A., 399.p. 499274 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.portional to the effective nuclear charge acting on that shell. Heemploys a method based on the wave mechanics t o calculate thiseffective nuclear charge, and is thus able to obtain the ratio of theradii of pairs of ions.To get the actual sizes, he uses as his startingpoint the experimental interionic distances, giving the sum of thetwo “ radii,” in NaF, KCl, RbBr, and CsI, together with an assumedvalue for Li of 0.608. obtained from the experimental distancein lithium oxide. We give in Table I a number of the ionic radii socalculated, compared with the empirical values given by V. M.Goldschmidt.2 It will be seen that the agreement on the whole isvery good.TABLE I.(Ionic radii, in Angstrom units.)Goldschmidt 1.32 1.33 1-52 0.98 0.78 0.67 0.39 0.3-0.4 0.34Pauling ...... 1.40 1.36 0.95 0.65 0.60 0.41 0.34 0.290-8.F-l. Ne. Nal. Mga. AP. Si4. P5. S6.The values used for 0-2 and F-l by Goldschmidt are those deducedby J. A. Wa~astjerna.~ Since, from empirical data from crystalswe cannot obtain the actual radius, but only the sum of two radii,we must assume the radius of at least one ion, and Wasastjerna’svalues are here taken as the starting point. The above table showsonly a few values; many more me given in the papers to whichreference has been made.The Relation between Crystal Strucfure and the Nature of theAtoms taking Part in it.In a series of papers briefly mentioned in last year’s Report,V. M. Goldschmidt has given an interesting survey of the differenttypes of crystal structure formed by the simpler compounds, andof the conditions under which one or other of these types occurs.Although many of the ideas emphasised have been implicit in agood deal of the work on crystal structure, they are summarisedvery clearly and much new matter is included.The whole is basedupon a mass of experimental work, most of which has been carriedout in Goldschmidt’s laboratory at Oslo. Reference may bemade to a good summary of the work, the material of a lecture byGoldschmidt 4 to the German Chemical Society. Goldschmidtpoints out that purely geometrical considerations, based on the ideaof an ionic radius characteristic of each ion, play a very importantpart in determining which type of structure is formed, particularly2 “ Geochemische Verteilungsgesetze der Elemente,” VII and VIII, NorskeVidenskape-Akad.(Mat. Nut. KZ.), 1926, Nos. 2 and 8.2. phyeikal. Chem., 1922, 101, 193; A., 1922, ii, 491,4 Ber., 1927, 60 [B], 1263; A., 611CRYSTALLOQRAPHY. 275when the constituents are simple ions having the inert-gas structure.It is supposed that one important condition for the stability of anionic structure is that anion and kation may touch one another.The number of ions of type X which can surround and touch an ionof type A depends on the ratio of the radii of A and X, supposingeach ion to be a sphere with a definite radius. In Table 11, which istaken from Goldschmidt’s work, are shown, in the first column thenumber of ions X which are supposed to surround and touch an ionA ; in the second the number and arrangement of the ions X aroundA, and in the third the smallest value of the ratio of the radii of theions, Rd/RY, which is permissible in order that such an arrangementmay be possible.It is to be emphasised that the essential point isthe contact of X and A.TABLE 11.Arrangement of X Ions around the Ion A.Number of Limiting ratioions X. Arrangement of X. RAIRx.3 At corners of an equilateral triangle. 0.164 At corners of a tetrahedron (ZnS) 0.224 0.416 0.418 0.73At corners of a square in the plane of A.Along the edges of a cube, A at corner (NaCl) ;At corners of a cube with A in the middle.or at corners of an octahedron.We may now consider the different types of compound AX andAX, with respect to the co-ordination of the ions one to another.In the zinc sulphide lattice, each ion has four neighbours of theopposite kind, in NaCl and NiAs, six, and in CsC1, eight.For lattices of the type AX, there are twice as many ions of theopposite sign around A as there are around X.For the differenttypes of lattice the numbers are as follows : CO,, 2 and 1; SiO,,Cu,O, 4 and 2 ; TiO, (rutile or anatase), CdI,, MoS,, 6 and 3 ; CaF,(fluorite), 8 and 4.Now, so long as we are dealing with simple ionic structures, it isfound that the type of lattice formed by a pair of ions can generallybe predicted by ascribing to each ion one of the radii discussed inthe preceding section, and taking into consideration the limitingratios of the radii for different types of co-ordination. A few ofthe many examples given may be quoted.Of the fluorides of the bivalent metals, MgF,, NiF,, CoF,, FeF,,ZnF,, and MnF, have the rutile structure with co-ordination numbers6 and 3, whereas CdF,, CUP,, HgF,, SrF,, PbF,, and BaF, have thefluorite structure with co-ordination numbers 8 and 4.The seriesas given is arranged in ascending order of RA/Rx. The value ofthe ratio for MnF, is 0.68, and for CdF, 0.77, whereas the limitingvalue of the ratio for the transition from the one type of co-ordin276 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.ation to the other is seen from Table I1 to be 0.73. Further, theoxides, sulphides, selenides, and tellurides of Mg, Cay Sr, and Ba allhave the rock-salt structure (co-ord. number 6) except MgTe, whichhas the wurtzite structure (co-ord.number 4). For the rock-saltstructure the ratio RA/Rx must be between 0.41 and 2.45; MgTe isthe only compound of this whole series in which the ratio fallsoutside these limits, its value being 0.37. The atomic radii cannotbe treated as exactly constant. There is a definite decrease as theco-ordination number decreases, and thus the limits are onlyapproximate; but there is no doubt that for a large class of com-pounds purely geometrical considerations of this kind are moreimportant than chemical considerations in determining the type ofcrystal structure.Geometry is not, however, the only factor. If one of the ions ismuch more readily polarisable than the other, so that it tends tobecome an electric dipole under the action of a field, this may havegreat influence on the actual structure, although geometricalconsiderations will remain as an important factor.Eachcadmium ion lies between six iodine ions, and the iodine has threecadmium ions as nearest neighbours.The crystal forms sheetscomposed of two layers of iodine atoms held together by thecadmium in between them. The iodine ions will be stronglypolarised by the cadmium ions. Each sheet is a very rigid structure.Adjacent sheets, however, are only lightly held together so that thecrystal has a very perfect cleavage. Lattices of this type have beentermed “ Schichtengitter,” or “ layer lattices,” by F. H ~ n d . ~The condition for such a layer lattice appears to be that one of theconstituents should be readily polarisable.This is illustrated bythe following fact. Cadmium fluoride has the fluorite structure.If we replace F’ by OH’ we get a layer lattice.6 Geometrically,OH’ occupies about the same space as F’, but it is a natural dipoleand so the layer lattice is formed. Similarly, if in SnO, or TiO,we replace 0” by S”, which is more readily polarisable, the rutilelattice changes to a layer lattice of the cadmium iodide type.’The lattices so far considered are of the purely ionic type, althoughmodified by polarisation effects. We must now consider brieflysome lattices which are certainly not ionic. One of the types ofAX lattice is typified by nickel arsenide, NiAs. The arsenic atomsare here nearly in hexagonal close-packed array. The nickelatoms lie in the gaps in the structure, between six arsenic atoms,6 2.Physik, 1925, 34, 833; Physikal. Z., 1926, 26, 682; A., 1925, ii, 1132.6 G. Nattrt, Atti R. Accad. Lincei, 1925, [Vi], 2, 495; A., 1926, 228.5 A. E. van Arkel, Physica, 1924, 4, 286; A., 1926, ii, 749,An example is given by the cadmium iodide latticeCRYSTALLOGRAPHY. 277The series of sulphides, selenides, and tellurides of Ca, Mn, Fe, Co,and Ni show a transition from the NaCl structure to the NiAsstructure with increasing atomic number of either ion. There is atthe same time a considerable decrease in the interatomic distancebelow that appropriate to an ionic lattice of the rock-salt type forthe same elements. One remarkable fact about lattices of thistype is that more or less free isomorphous replacement seems totake place between the components.For example, ferrous sulphideand sulphur form an isomorphous mixture in which the excess ofsulphur appears to be able to replace iron in a lattice of the NiAstype.* Goldschmidt and his co-workers found the same thing forCoSe, MnSb, and FeSb, and suggest that the formula of suchcompounds might better be written Fe,Sb, and so on. Suchlattices seem only to be formed when the metallic atom belongs tothe series from scandium to nickel in which there is a deficiency ofelectrons in the M-group. Goldschmidt goes so far as to suggestthat part of the negative charge of the anion either directly orindirectly tends to make good this deficiency. Assuming that adeficiency in an inner electron group in the kation, and a large andreadily polarisable anion are the essentials for this type of structure,Goldschmidt argues that compounds of metals of the platinumgroup with readily polarisable ions should show the NiAs structure.This has been verified for the compound PtSn.Another type of lattice of great interest is that in which eachcomponent has four neighbours, the zinc blende or wurtzite lattice.The geometrical condition for such a lattice is a ratio of radii between0.22 and 4.5, but there seems to be a further condition, which waspointed out by M.L. Huggins and by H. G. Grimm and A. Sommer-feld.1° The condition is that the element A must be as many places(up to three) in the periodic table before one of the elements, C,Si, Ge, Sn, Pb, as the element X is beyond it.The sum of theouter electrons of the two components must therefore be eight.The lattice which is so formed is not a simple ionic lattice, as can beseen by studying the atomic distances in the series given in Table 111,which was investigated by Goldschmidt. Grey tin forms a latticeof the diamond type ; the other compounds in the series are formedTABLE 111.Atomic number. Compound. Lattice constant. Atomic distance.60,50 SnSn 6-46 A. 2-79 8.49,51 InSb 6.452 ,, 2.793 ,,48,52 CdTe 6-463 ,, 2.799 ,,47,63 AgI 6.491 ,, 2.811 ,,N. AlsCn, Geol. F6r. Ftjrh., 1925, 47, 19.Physica2 Rev., 1926, [ii], 27, 286; A., 1926, 458.lo 2. Physik, 1926, 36, 36; A., 1926, 560278 ANNUAL REPORTS ON THE PROGRESS OF CHENISTRY.by increasing the atomic number of one component above thatof tin and decreasing that of the other by the same amount belowit, so that the sum of the atomic numbers remains 100.The mostremarkable thing about the series of compounds so formed, all ofwhich crystallise on the zinc blende (diamond-like) or wurtzitelattices, is the constancy of the interatomic distance. We should notget this constancy in a similar series of compounds of the sodiumchloride type. If we take another of the quadrivalent elementsas the starting point, we get another series, with a different constantatomic distance. We must refer the reader to Goldschmidt’s workfor a complete table of such compounds. The lattice here is not anionic lattice, neither in all probability is it, strictly speaking, atomicor molecular.Goldschmidt concludes that the individuality ofthe single elements matters but little. There seems to be a commonstructure of the whole crystal, the dimensions of which are controlledalmost entirely by the total number of negative charges, andscarcely a t all by the distribution of the positive charges on the singleatomic nuclei. I n the next section we shall see that similar con-siderations are true for alloys and intermetallic compounds. Indeed,both in the NiAs and the wurtzite types of structure many of thecrystals have a metallic lustre and appearance. Such crystals mayrepresent a transition stage between the non-metallic compound andthe true metals.The Crystal Structure of Alloys.In a previous Report l1 some account was given of the work ofA.Westgren and G. Phragmdn on the copper-zinc, silver-zinc,and gold-zinc alloys. These authors have extended this work, andhave found that four types of crystal structure are common to eachof these series of alloys, and to certain other alloy systems.12 Theseare (1) face-centred cubic, (2) body-centred cubic, (3) hexagonalclose-packed, and (4) a complex cubic structure.The face-centred structure is the structure of the pure metals,copper, silver, and gold. When small quantities of zinc, aluminium,or tin are added to these metals no change is produced in the type ofcrystal structure. The atoms of the one kind are replaced by those ofthe other kind, atom by atom, producing an arrangement which, sofar as X-ray analysis can tell, is indistinguishable from that of a puremetal.Such an arrangement is a solid solution, and is character-ised by the fact that atoms of different kinds behave in an identicalA.nn. Reports, 1925, 22, 253.If 2. Metallk., 1926, 18, 279; A., 1926, 1084. Compare also E. A. Owenand G. Preston, PTOC. Physical SOC. London, 1923,36,49 ; M. Andrews, PhysicdRev., 1921, [GI, 18, 245CRYSTALLOGRAPHY. 279manner, being distributed a t random throughout the structure.This arrangement is only possible when the alloy contains largeproportions of the parent metal, d.e., the metal which has thesame structure as the solid solution. With greater quantities of theforeign element, the structure breaks down and the atoms proceedto arrange themselves in quite a different way.One of these alternative structures is a peculiar complex cubicarrangement, which possesses many remarkable features.Thisarrangement is formed by copper, silver, or gold alloyed with zinc,and by copper alloyed with aluminium or tin. Although thestructures are very similar in each case, there is actually a progressiveincrease of complexity in passing from the zinc alloy to thealuminium alloy, and from the latter to the tin alloy.The arrangement of the atoms in the copper-zinc alloy has beendetermined.13 The type of co-ordination is remarkable, each atombeing surrounded by 11, 12, or 13 neighbours at approximatelyequal distances, each neighbouring atom being as far as possible ofthe opposite sort.This structure is stable over a wide range ofconcentrations, the zinc content varying from a value correspondingto the formula Cu,Zn, to one corresponding to Cu,Zn,. The atomsactually appear to be divided in a manner that would correspond tothe formula Cu,Zn8, any excess of zinc atoms replacing individualcopper atoms in a random manner, so that the phase is a solidsolution based on the compound Cu5Zn,. The same is true of thesilver and gold alloys, which are based on the formuls Ag5Zn,and Au 5Zns, respectively.The element manganese,l* in the a-form, bears a striking resembl-ance to these complex cubic alloys. It contains 58 atoms in a cubeof approximately the same size as the unit cube of the alloy, and thereis a somewhat similar disposition of atoms.The distance betweenneighbouring atoms, however, varies considerably. All these factsseem to indicate that a-manganese contains atoms which are in someway different in character, so that the structure is akin to that of analloy rather than to that of a true element.The complex cubic alloys of zinc with copper, silver, and goldall have compositions corresponding to the same atomic percentages,SO that the resemblance is in this case a typical instance of isomor-phism, and presents no unusual features when viewed from thenormal chemical standpoint. The relationship between the alloysof copper with zinc, aluminium or tin is, however, less simple.As the valency of the replacing atom (Zn, Al, or Sn) increases, phasescorresponding to the complex structure become richer in copper.l8 A.J. Bradley and J. Thewlis, Proc. Roy. SOC., 1926, [ A ] , 112, 678; A.,1926, 1084. 14 Idem, ibid., 1927, [A], 115, 456; A,, 814280 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.A similar shift incomposition was found in the case of the hexagonalstructures which Westgren and Phragmen investigated. Theytraced the existence of a hexagonal close-packed type of structurein binary alloys of silver with zinc, aluminium, or tin. The silvercontent of the alloy is found to be greater for tervalent aluminiumthan for bivalent zinc, and still greater for quadrivalent tin.Westgren and Phragmh suggest that the ratio of the number ofvalency electrons to the number of atoms is a significant factor indeciding the nature of the atomic arrangement in such cases as these.This is by no means unlikely, for W.Hume-Rothery l5 has alreadypointed out that the three alloys the empirical compositions ofwhich may be represented by the formulae CuZn, Cu,AI, and Cu5Snhave very similar microstructures, and has suggested that this isdue to the fact that the ratio of valency electrons to atoms is in eachcase 3 : 2. He further suggests that these alloys all possess thebody-centred cubic structure, which Westgren and Phragmkn haveshown to be typical of the p-phases of the alloys copper-zinc, silver-zinc, and gold-zinc. These alloys correspond to the formulaeCuZn, AgZn, and AuZn, so that an arrangement of the atoms as inthe case of CsCl is possible.This czesium chloride structure hasalso been shown by E. A. Owen and G. D. Preston l6 to holdgood in the case of the analogous alloys AuZn and AgMg.Two recent papers by C. H. Johansson and J. 0. Linde,l7 whohave tried to establish a relationship between crystal structure andelectrical conductivity, are of great interest. Copper can bealloyed with gold, platinum, or palladium in all proportions, givinga series of alloys which are ideal solid solutions, consisting only of asingle face-centred cubic lattice with a random distribution of theconstituent elements. I n any such series of alloys the electricalconductivity decreases continuously with a rising percentage of thesubstituent metal, until it finally reaches a minimium and thensteadily rises as the substituent metal becomes the dominant con-stituent.Johansson and Linde show, however, that, when theconstituents occur in certain definite proportions, prolonged anneal-ing at temperatures below 400" produces a remarkable increase inthe electrical conductivity of the alloys. At the same time, new linesappear on the X-ray photographs obtained from the alloys, whichshow quite definitely that a rearrangement of the atoms has takenplace, and that the constituent elements are no longer distributedin a haphazard way. For example, the alloys of copper with gold,lS J . Inst. Metals, 1926, 35, 313; A., 1926, 356.l6 Phil. Mag., 1926, 2, 1266; A,, 1927, 96.Ann. Physik, 1925, 78, 439; 1927, 82, 449; A., 1926, 112; 1927, 400.Compare also E.C. Bain, Chem. Met. Eng., 1923, 28, 21CRYSTALLOGRAPHY. 281platinum, or palladium show a f ace-centred cubic arrangement,with, in general, a random distribution of the elements; but withalloys containing 75 atoms yo of copper, rearrangement takes placeon annealing in such a way that the atoms at the centres of thecube faces are copper, and those a t the cube corners the other metal.The increased conductivity and the regular arrangement of atomsinvariably occur together. Reheating a t a temperature above 400"removes both the extra conductivity and the new X-ray lines.Similar rearrangement takes place when the alloys contain 50atoms yo of each constituent. The crystal structures differ,however, with the different elements, the gold alloy being tetragonal,the platinum alloy trigonal, and the palladium alloy cubic, with acaesium chloride type of structure.According to G.Tammann,l8 any solid solution may be expectedto produce a regularly arranged structure if annealed under suitableconditions; but the work of Johansson and Linde seems to showthat such rearrangement is exceptional and can only occur atcertain concentrations, the resulting structures being in fact inter-metallic compounds. From this point of view, an intermetalliccompound may be merely a special case of a solid solution, in whichthe random distribution has been replaced by a more regular dis-tribution of the atoms of different types.Crystal Structures of Metallic Elements.G. Asahara and T. Sasahara l9 have investigated the crystalstructures of metallic thallium, using single crystals prepared byelectrolysis.They find the structure to be hexagonal close-packed,thus confirming the work of G. R. Levi,Z0 which had been questionedby K. Becker.21The crystal structure of metallic gallium 22 has been found to betetragonal, containing eight atoms per unit cell. There are twoparameters which have not been determined.F. Simon and E. Vohsen 23 have determined the crystal structureof the alkali metals Na, K, Rb, and Cs and find them all to be body-centred cubic. The result for potassium conflicts with that givenby V. M. Goldschmidt, who finds it to be tetragonal.18 " Lehrbuch der Metallographie " (Leipzig), 2nd edn., 1921, p. 329.lo Sci. Papers Inst.Phys. Chem. Rea. Tokyo, 1926,5, 79, 82; A., 1927, 814.Zo Cim., 1924, 1, 1 ; 2. Physik, 1927, 44, 603; A., 1013.21 Ibid., 45, 450; A., 1129.22 F. M. Jaeger, P. Terpstra, and H. G. K. Westenbrink, Proc. K. Akad.28 Natumoiss., 1927, 15, 398.Wetenech. Amsterdam, 1926, 29, 1193; A., 1927, 297282 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Inorganic Crystals.Co-ordination Compounds.-The present state of the chemicaltheory of the nature of the atomic linkage in co-ordination com-pounds was summarised by N. V. Sidgwick in his PresidentialAddress to the Chemistry Section of the British Association inSeptember 1927. The investigation of these compounds by X-raymethods is a matter of difficulty, since, owing to their complexity,the detailed elucidation of their structures is limited to those ofhigh crystallographic symmetry ; but enough information hasalready been obtained to support the general conclusions as to thestereochemistry of co-ordination compounds originally put forwardby Werner.The following compounds have been examined.FIG. 1.?II*--..--II0Structure of [Co(NR,),]I,, showing unit cell. The large ojin circles representiodine atoms, the large black circles Co(NH,), groups. The partial detail ofthese groups is shown in the smaller diagram. 1 he small black circle representsthe cobalt atom, the small open circles NH, molecules.Hexa-amminocobaltic iodide, [Co(NH,) ,]I,.* The crystal is cubic,the unit cell of side 10.88 8. containing four molecules. Theatomic positions in the unit cell are shown in Fig.1, from which itwill be clear that the structure may be regarded as built on a latticewhich combines the NaCl and CaF, lattices. The lattice pointsaccommodate iodine atoms and co-ordination groups Co(NH,),.One set of iodine atoms and the Co(NH,), groups form a rock-saltlattice, whilst the other two sets of iodine atoms form with the samegroups the CaF, lattice. The ammonia molecules are arranged24 R. W. G. Wyckoff and T. P. McCutcheon, Amer. J . Sci., 1927, [v], 13,223; A., 400; H. Rentschel and F . Rime, Math.-Php. Kl. Suchs. Akad.,1927, '79, 1 ; H. Meisel and W. Tiedjo, 2. anorg. Chem., 1927, 164, 223; A.,923CRYSTALLOGRAPHY. 283octahedrally about the cobalt atom, as anticipated in the co-ordin-ation theory.This type of composite lattice is of frequentoccurrence, and reference is made to it elsewhere in the Report.Of exactly similar structural type is the compound[Co(NH3) 61(C104)3,25the side of the unit cell of the cubic crystal having the length 11.39 8.In this crystal, the oxygen atoms are arranged in fours about thechlorine atom, the perchlorate groups replacing the iodine atoms inFig. 1.An examination of (NH4)2PbC16,26 cubic (a = 10.14 A.), shows theunit cell to contain four molecules. The structure is of the CaF,type in which calcium is replaced by the co-ordination groupPba6-eaCh lead atom being surrounded by 6 chlorine atoms-andfluorine by the ammonium group. The structure is thus similart o that of the analogous salts K2PtC1, and K,SnC16.Of similar type, with obvious structural substitutions, are[ C O ( ~ , ) , ] I , , ~ ~ CS,G~F,,~~ and [N(CH3),]2PtC1,.29 Further ex-amples of co-ordination compounds occur in later sections.Water of Crystallisation.-Owing to the complexity of hydratedcompounds in general, they have not received much attention inX-ray crystallography.E. J. Cuy 30 discusses the tendency of simplecompounds to form hydrates and ammoniates, and the stabilityof such hydrates; he concludes that the question depends on therelative sizes of the ions forming the original compound.With the idea of examining the geometrical significance of waterin hydrated compounds, S. B. Hendricks and R. G. Dickinson31have determined the crystal structures of ammonium, potassium,and rubidium cupric chloride dihydrates (R2CuC14,2H20). Thecrystals, which are tetragonal, have two molecules in the unit cell.The structure is of the calcium fluoride type (the unit cell is almostcubic), in which copper takes the place of calcium and R that offluorine.Four chlorine atoms and two H20 molecules are arrangedoctahedrally about each copper atom, thus forming a cupric chloridedihydrate co-ordination group. The group is, however, somewhatdistorted, the two pairs of chlorine atoms involved being at different25 R. W. G. Wyckoff, S. B. Hendricks, and T. P. McCutcheon, Amer. J.26 R. W. G. Wyckoff and L. M. Dennis, ibid., 1926, [v], 12, 503; A., 1927,27 H. Hentschel and F. Rinne, Math.-Phys. Iil. Sachs. Akad., 1927, 70, 1.28 R.W. G. Wyckoff and J. H. Miiller, Amer. J . Sci., 1927, [v], 13, 347;Sci., 1927, [v], 13, 388; A., 502.97.A., 503.M. L. Huggins, P h y k a l Rev., 1926, [ii], 27, 638; A., 1927, 1014.30 J. Amer. Chem. SOC., 1927, 49, 201; A., 191.a1 Ibid., p. 2149; A., 1013284 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.distances from the copper atom. This distortion is regarded ascorresponding to lack of stability in the co-ordination group.0. Hassel and J. R. Salvesan 32 have examined a series of hetero-polar hexahydrates of the type MG,,LR, where G and R may beH,O and halide, respectively. Thus, in the case of zinc fluosilicate(ZnSiF6,6H,0), the structure is such that one set of ions representinga co-ordination group (Zn,6H20) occupies the corners of a rhom-bohedron of angle 96", the other complex, SiF,, being a t the centreof the rhomb.This rhomb is not, however, the true unit cell;apparently the octahe*al arrangements of the H20 molecules andfluorine atoms about the zinc and silicon respectively are such asto cause the true unit cell to be four times that of the rhomb justmentioned, and the final rhombohedra1 angle to be 112". In addi-tion to this series of compounds, the following were found to possessthe same structure : [co( NH,) ,]Co( CN) ,, [co( NH,) 5,H,0]Co( CN) 6,J. M. Cork33 has recently re-investigated the structure of thealums, KCr(SO4),,12H2O and RA1(S0,)2,12H20, where R is in turn(NH,), K, Rb, Cs, and T1. The unit cell is cubic, of average side12.2 8., and contains four molecules ; the cell dimensions vary littlethroughout the series.The structure may be regarded as beingbuilt on a distorted form of the composite lattice illustrated in Fig. 1.Each metal atom is symmetrically surrounded by six molecules ofwater, and each sulphur atom by four oxygen atoms. The sulphuratoms lie on the trigonal axes of the cell nearer to the tervalentmetal than to the univalent metal.Mixed Crystals.-Several papers have recently appeared on thecharacter and conditions of formation of mixed crystals, but thereis still considerable doubt as to the distribution of the constituentatoms in such crystals. The possibility that a mixed crystal is acomposite of pure crystals of the two constituents is unlikely,since the presence of two different lattices would be revealed byX-rays.Objections of a theoretical nature are put forward byH. G. K. Westenbrink S4 against the suggestion that isomorphoussubstitution takes place atom by atom in a perfectly regular manner.G. Lunde 35 suggests that perfect mixture of the constituents occurs,but that the manner of atomic replacement is purely arbitrary andwithout regularity. The general conclusions to be drawn from theexperimental results appear to be as follows :(a;) Mixed crystals may be formed from constituents whose[Co(NH,),,H2°1Fe(CN)8, [Co(NH,)4,(H,0)21Co(CN)6.32 2. physikal. Chem., 1927, 128, 345; A., 1014.33 Phil. Mag., 1927, 4, 688.34 Rec. trav. chim., 1927, 46, 105; A,, 400.36 BulL SOC. chim., 1927, 41, 304; A., 400CRYSTALLOGRAPHY. 285individual lattices differ considerably in size.For example, T.Barth and G . Lunde 36 were able to prepare series of mixed crystalsfrom halogen compounds of certain heavy metals (large lattices)with those of alkali metals (smaller lattices).( b ) In such cases, in general, the resulting lattice varies in 8,simple manner with the relative proportion of the constituents.Thus, L. Vegard,37 in the case of mercurous chloride and bromide,found a linear increase in the lattice constants as the molecularcontent of the bromide increased from 0 to 100%. He also foundthat the rate of precipitation affected the size of the resulting lattice,the linear law holding for slow rates.( c ) Mixed crystals may be formed from constituents whoselattices differ in character.Thus, T. Barth and G. Lunde 38 foundthat thallous bromide (body-centred cubic) and thallous iodide(rhombic) form mixed crystals the lattice of which may be cubicor rhombic according to the proportion of the constituents, bothtypes existing in the middle of the series. One crystal thus appearsto be able to accommodate itself to the structure of the othercrystal to some extent. This power of accommodation, however,is not necessarily equally shared by the two constituents. Thusin mixed crystals of silver bromide (cubic rock-salt type ; a = 5.76 8.)and silver iodide (cubic zinc-blende type ; a = 6.49 A.) both typesmay occur, but the bromide is able to include in its structure alarge percentage of the iodide, although the converse is not true.(d) In cases where the constituents are coloured, the mixedcrystals often show a deeper colour than either constituent.ThusBarth and Lunde (Zoc. cit.) found this to be true for CuI-AgI andAgBr-AgI. They regard the coloration as due to distortion of theions in fitting into the new lattice.(e) L. Vegard and T. Hauge39 find evidence by X-rays of theformation of mixed crystals when potassium bromide and chlorideor when mercurous bromide and chloride in the solid phase areplaced in contact. They suggest that an exchange of atoms betweenthe crystal lattices occurs.8iZicates.-Reference was made in last year's report to the specialr6le played by the oxygen atoms, owing to their predominant sizeand number, in many of the complex silicates.A general discussionof this subject with examples from recent new work is given in apaper by W. L. Bragg and J. West." The following examples maybe mentioned.36 2. physikal. Chern., 1926, 122, 293; A,, 1926, 895.3 1 2. Physik, 1927, 43, 299; A., 815.39 2. Phyaik., 1927,42, 1 ; A., 604.40 Proc. Roy. Soc., 1927, [A], 114,450; A,, 601 ; Proc. Roy. Inat., 1927,25,302.Norsk Geol. Tidsskrift, 1926,8, 293286 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.Cyanite (one of the forms of N,SiO,). The crystal is triclinic, theunit cell, containing four molecules, being defined by a = 7.15,b = 8.00, c = 5-55 8., a = 90" 54', F = 101" 2', y = 105" 444'.In spite of the irregular character of this cell, it was found possibleto fit it into a scheme of oxygen atoms (diameter 2-70 8.) arrangedin cubic close packing, an arrangement which was verified by anX-ray examination of the crystal.The low symmetry of thestructure is thus due to the complexity introduced by the distribu-tion of aluminium and silicon atoms amongst the interstices in theoxygen arrangement. Although this distribution is not determined,it is anticipated by analogy with other silicates that the aluminiumand silicon atoms are respectively surrounded by groups of six andfour oxygen atoms.The chodrodite series 41 [Chondrodite, Mg( OH),,2Mg2SiO,, mono-clinic ; humite, Mg( OH),,3Mg,Si04, orthorhombic ; clinohumite,Mg( OH),,4Mg,Si04, monoclinic]. The members of this series beara strong crystallographic resemblance to olivine (Mg,SiO,) and,with it, afford an interesting example of morphotropy; for, whilsttwo edges of the unit cell remain practically constant throughoutthe series, the thickness measured perpendicular to these edgesvaries in definite steps which are simply related to each other.Thethree structures may be described as being formed of alternatelayers-parallel to the c face-of Mg(OH), and Mg,SiO,, based onan arrangement of oxygen atoms and hydroxyl groups in hexagondclose packing. In this case, as in that of cyanite, the oxygen atomsappear to determine the dimensional relations, whilst the metaland silicon atoms control the symmetry in the unit cell. Thelayers of Mg,SiO, are found to possess the olivine structure.Phenacite (Be,Si0,).42 The unit cell, which is rhombohedra1 andcontains six molecules, has an angle of 108" 1' and a side of length7.68A.The arrangement of oxygen atoms differs somewhat fromthat in the preceding example in being more open. The trigonalaxes in the structure are contained within narrow channels devoidof atoms, although elsewhere there is close packing. The structuremay be regarded as built up of slightly staggered rows of oxygenatoms in contact parallel to the trigonal axes. These parallel rowsmay be divided into groups of four, arranged to form a new columnof Y-shaped section. The Y-shaped columns are then packedtogether so that one column relative to its neighbours is displacedparallel to its length (and therefore to the trigonal axes) by anamount equal to the radius of an oxygen atom (1.35 A.). The siliconatoms, and probably also the beryllium atoms, lie within groups offour oxygen atoms.4 1 W.H. Taylor and J. West, PTOC. Roy. SOC., 1928, [A], 117, 517.a W. L. Bragg, &bid., 1927, [A], 113, 642; A,, 97CRYSTALLOGRAPHY. 287A recent determination 43 of the space groups of the members ofthe dioptase group-diopfase, phenacite, willemite, and troostife-shows that all four crystals have the symmetry of C&. The simi-larity in the X-ray diffraction patterns suggests that the phenacitestructure is common to the series.An interesting paper by R. W. G. Wyckoff and G. W. MoreyUdescribes an X-ray investigation of compounds in the systemsoda-lime-silica.Of the four silicates of sodium and calcium,two-the orthosilicate, Na,CaSiO,, and metasilicate, Na4Ca(Si03)3-are optically isotropic, the third, Na2Ca2(Si03)3, is slightly doublyrefractive, whilst the fourth, Na2O,3CaO,6SiO,, differs from theothers crystallographically and optically. The X-ray difiractionpatterns of the first three, and especially of the first two, show astrong similarity, although the third is definitely not cubic, thesecond probably only pseudo-cubic, and all three differ widely inchemical composition. Advantage was taken of the high symmetryto examine the structures of the ortho- and meta-silicates. Althoughthat of the latter is not certain, it is considered probable that thesilicon atoms are surrounded by four oxygen atoms.The unit cellof the orthosilicate is cubic, of side 7.50A., and contains fourmolecules. The oxygen atoms are arranged in groups of four abouteach silicon atom. The structure may be regarded as a distortionof a composite lattice of the NaCl and CaF, type (see Fig. 1) in whichthe Ca and SiO, groups are arranged as Na and C1 in rock-salt, andthe Na and SiO, groups as F and Ca atoms in fluorspar. The authorsdirect attention to the frequency of this structure for ionic compoundsconsisting of four groups. From a consideration of such compoundsas [Co(NH,) J13, (NH,),AIF,, and Na,CaSiO,, they conclude that“ there is no obvious connection between the crystal structure of acrystal and the valency of its atoms.”A further attempt to classify the micas 45 illustrates the difficultyof assigning to the more complex silicates formulae having chemicalsignificance. In the present case, the micas are regarded as ‘‘ saltsof an acid with a constant number (six) of silicon atoms.” Thisclassification is based on the observation that the ratio R,O : SiO,=I : 6 is constant throughout the series.Isomorphous Substitution.-The substitution of one set of atomsor group of atoms for another in a series of compounds, is notonly of use in giving information of chemical value, but in the caseof isomorphous series of complex solid compounds it can be a43 G.Gottfried, Neue Jahrb. Min., 1927, [A], 55, 393.44 Arner. J. Sci., 1926, 12, [v], 419; A., 1927, 10.*j *4. F. Hallimond, Min. Mag., 1925, 20, 305; A., 1925, ii, 819; 1926,21, 25, 195; A., 1926, 816288 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.useful aid to the determination of the crystal structure by X-rays.The investigation of the alums quoted above is an example.Afurther example is that of the alkali sulphates of type R,S0,.46 Thesulphates of K, T1, (NH,), and Cs were examined. The smallscattering power for X-rays of the (NH,) group permitted the moredefinite location of the sulphur atoms, whilst the relatively largescattering power of the czesiurn atom aided the location of the Ratoms. The structure, as in other sulphates investigated, contains(SO,) groups; each R atom is surrounded by six oxygen atoms.The unit cell is orthorhombic, contains four molecules, and possessesthe symmetry of Vk6.The atomic arrangement deduced explainsthe pseudo- hexagonal character of these sulphates .Another isomorphous series recently examined is that of thetetragonal scheelite The structures of BaWO,, PbWO,,BaMoO,, and PbMoO, are found to be identical with that ofscheelite (CaWO,), in which the metal atoms may be regarded asarranged in a diamond type of lattice expanded in the direction ofthe c axis, the tungsten atoms being surrounded by four oxygenatoms. The replacement of calcium by barium or lead causes aconsiderable expansion of the scheelite lattice, the effect beinggreater for lead.The series xenotime (YPO,), zircon (ZrSiO,), rutile (TiO,), andcassiterite (SnO,) 48 is interesting as an example of a case wheremorphological isotropy is not necessarily accompanied by structuralsimilarity.The similar structures of the first two crystals arefound to differ from the similar structures of the second two.Colour and Crystal Structure.-0. R. Howell 49 points out that itis in some cases possible to predict the structure of a crystal from itscolour. It has been shown 50 that, when a metallic atom in a colour-less insoluble compound is replaced by cobalt, a pigment is obtainedwhich is blue if the cobalt is surrounded by four other atoms, andred if it is surrounded by six. From the colour of pigments, pre-pared in this way from compounds of unknown crystal structures, itwas possible to predict in some measure the structure of the com-pound from which it was derived.For example, a blue compound isobtained when cobalt replaces zinc in zinc orthosilicate, whereasfrom magnesium orthosilicate a red pigment is obtained. Thestructures of both these silicates have now been determined :46 W. Taylor, Proc. Mancheater Lit. Phil. Soc., 1927 (in the press) ; A. Ogg,Phil. Mag., 1928, 5, 384.47 L. Vegard and A. Refsum, Skr@er Norske Vdenskaps-Akad., 1927, 1,No. 2.48 L. Vegard, ibid., No. 6.4@ J., 1927, 2843.60 R. Hill and 0. R. Howell, Phil. Mag., 1924, 48, 833; A., 1924, ii, 817CRYSTALLOGRAPHY. 289W. Zachariaaen 51 finds zinc orthosilicate to be isomorphous withphenacite, Be,SiO,, in which the beryllium atom is between fouroxygen atoms,& whereas the work of W. L. Bragg and G. B. Brown 52on olivine has shown that in Mg,SiO, each magnesium atom issurrounded by six oxygen atoms.Other examples are given inHowell's paper.Crystal 8tructure of Boron Nit~ide.~~-Prepared crystals of BNwere found to show a similarity in form and structure to graphiteand not to diamond as was previously expected.54 Each nitrogenatom is surrounded by three equidistant boron atoms and vice versa.Solid O~ygerc.~~-X-Ray examination at -252" reveals a body-centred orthorhombic cell of dimensions a = 5.50, b = 3.82, c =3.448., containing two molecules. This is considered to be thelower-temperature modification.Theoretical Determinations of Crystal Par~meters.~~J. E. Lennard-Jones and (Miss) B. M. Dent have extended theirwork on the determination of crystal parameters from the inter-atomic forces, of which an account was given in last ybar's report,to other crystals with one parameter-the rutile group, chloro-stannate and chloroplatinate of potassium, and solid carbon dioxide.Their results for the last are of interest, since they show a distanceof 0.90 8.between carbon and oxygen; this is in fair agreementwith the value obtained by X-ray analysis by J. de Smedt andW. H. M. Keesom,57viz., 1-05 8., but appears to negative the resultsof H. Mark and E. P0hland,~8 who obtained 1.59 8.Organic Crystals.The investigation of the detailed structure of organic crystals ispeculiarly difficult. They are in general of relatively low crystallo-graphic symmetry, the molecules are complicated, and a completedetermination involves the fixing of a large number of parameters.This can only be done by measuring the intensities of the X-rayspectra, and for organic crystals such measurements are usuallynot easy to make (suitable specimens being difficult to obtain),and extremely difficult to interpret.Most of the investigations of51 Nor8k Geol. TicEeskrift., 1926, 9, 65.52 2. Krist., 1926, 63, 638; A., 1926, 995.63 V. M. Goldschmidt and 0. Hwel, Suer. Nor8k Geol. Tids., 1926, 268.64 H. G. Grimm and A. Sommerfeld, 2. Phyeik, 1926, 36, 36; A., 1926,66 J. C. McLennan and J. 0. Wilhelm, Phil. Mag., 1927, [vii], 3, 383; A.,ti6 Phil. Mag., 1927, [vii], 3, 1204; A., 716.67 Proc. K . Akad. Wetensch. Amsterdam, 1924, 27, 839; A , , 1925, ii, 484.68 2. Krist., 1925, 61,293.REP.-VOL. XXIV.K660.297290 ANNUAL REPORTS ON THE PROQRESS OF CHEMISTRY.the structures of organic crystals have not attempted to go beyondthe space group.Space-group determinations may give useful information concern-ing the symmetry of the organic molecules. Of interest in thisrespect is recent work on the structure of a number of methanederivatives. On theoretical grounds a pyramidal structure, havingthe carbon atom at the vertex and the hydrogen atoms all in oneplane, has been assigned to the methane molecule itself.59 Workon the crystal structure of pentaerythritol, C(CH,*OH),, appearedto be in agreement with this; the arrangement of the groupsaround the single carbon atom was stated to be pyramidal,60 andwork on the external symmetry of the crystals61 was supposedto confirm this.Quite recently I. Nitta and S. B. Hendricks 63have published work in which they show that the space group ofthe crystal is Cf and that the molecule may have a fourfold alternat-ing axis of symmetry. This makes a tetrahedral molecule with thecarbon atom in the centre a possibility. Support to this view isgiven by some work of A. Schleede and E. Schneider G4 who concludefrom the growth of single crystals of pentaerythritol that thesymmetry is Sa or tetragonal alternating. The balance of evidenceat present appears to be in favour of a tetrahedral carbon atom inthis compound.In tetranitromethane H. Mark and W. Noethling 65 find that themolecule has a threefold axis. The carbon atom is thus tetrahedral,but only three of the nitro-groups are equivalent.The symmetrycorresponds to the structural formula O*NO*C(NO,),. In tetra-methylmethane they find a tetrahedral group. W. H. George 66has studied the isomorphism of the series carbon, silicon, germanium,and lead tetraphenyl. The crystals are tetragonal, and the unit cell,which contains two molecules, has an alternating fourfold axis ofsymmetry, parallel to the c-axis. The size of the square base of thecell increases and the height decreases with increasing atomicnumber of the quadrivalent element. The phenyl groups are in allcases arranged tetrahedrally about the central atom.V. Guillemin, jun.; Ann. Phy&ik, 1926, 81, 173; A., 1926, 1083.O0 H. Mark and K. Weissenberg, 2.Physik, 1923, 17, 301; A., 1923, i,1055; M. L. Huggins and S. B. Hendricks, J . Amer. Chem. SOC., 1926, 48,164; A., 1926, 227.O1 H. G. K. Westenbrink and F. A. van Melle, 2. Krist., 1926, 64, 648;A. Giebe and E. Scheibe, 2. Phy&k, 1925, 33, 346.O3 Bull. Chem. SOC. Japan, 1926, 1, 62; A., 1926, 665.63 Z. KTiSt., 1927, 66, 131.O4 Natumoise., Dec. 2nd, 1927.66 2. Krist., 1927, 6S, 436.Proc. Roy. Soc., 1927, [A], 113, 686CRYSTALLOGRAPHY. 291Long-chain Cmpounds.-A notable advance has been made byA. Muller 67 in the study of the structure of the long-chain com-pounds. He has succeeded in obtaining rotation X-ray photo-graphs and Laue photographs from small single crystals of stearic,bromostearic, stearolic, and behenolic acids. All the crystals aremonoclinic-prismatic. Chains of carbon atoms exist in all fourcrystals. The chains are packed in the crystal with their axesparallel to one another or nearly so, the distance between carbonatoms in the chains being much less than the distance betweenneighbouring chains. The crystal molecule appears in all casesto be a chain of carbon atoms, the number of atoms in the chainbeing the same as that in the chemical molecule. It will readily beseen that an arrangement of this kind will give parallel sheets ofcarbon atoms very closely and evenly spaced within the unit cell.The true unit spacing perpendicular t o the sheets will be large, butit will be very nearly exactly divided by the sheets of carbon atomsinto a much smaller spacing. Suppose, for example, that the chainconsisted of 19 exactly similar carbon atoms followed by LL carbonatom united with a different group A, and that this was repeatedindefinitely. The true spacing would be from an atom A to thenext atom A, and there would be a large number of orders of spectraon the rotation photograph corresponding to this very long spacing.Had all the carbon atoms been alike, only the 20th, 40th, 60th ofthese spectra would have appeared. Actually the atoms are notall alike, and the intervening spectra do occur, but only those nearthe 20th, 40th, 60th spectra are at all strong, since it is only forthese spectra that the contributions from all the carbon atoms arenearly in phase. Thus, by studying the periodic waxing and waningof the intensities of a large series of spectra, valuable information asto the arrangement of the carbon atoms can be obtained, evenalthough exact measurements of intensity cannot be made.It is interesting to note that the molecular cross-section parallelto the basal plane of the crystal, as determined by Muller, agreesvery closely with Adam’s estimate of the cross-section in his work onunimolecular surface films.In conclusion the authors wish to express their indebtedness toProf. W. L. Bragg, F.R.S., for many helpful suggestions during thepreparation of this Report.R. W. JAMES.J. WEST.A. J. BRADLEY.67 Proc. Roy. SOC., 1927, [A], 114, 642

ISSN:0365-6217    

DOI:10.1039/AR9272400273

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

MINERALOGICAL CHEMISTRY,GROTH is dead. Paul Heinrich Ritter von Groth (1843-1927)died on December 2nd at the ripe age of 849 years. He was Pro-fessor of Mineralogy in Strassburg during 1872-1883, and since1883 in Munich, and his laboratory was long the centre of trainingfor students from all parts of the world. In 1877 he founded theZeitschrift f u r Krystallographie und Mineralogie (carried on since1921 by Prof. Paul Niggli of Zurich under the title Zeitschrift furKristallographie), in which he obtained the willing co-operation ofworkers in all countries. As marking the jubilee of that periodical,he gave in vol. 66, only shortly before his death, an interestingreview of the work that had been done. His monumental work,‘‘ Chemische Krystallographie ” (5 vols., 1906-1919), collectstogether the crystallographic data for some 7350 substances.Theextent to which this is now being used by X-ray workers couldscarcely have been foreseen even by Groth himself. His well-known text-books “ Physikalische Krystallographie ’’ and “ Tabel-larische Ubersicht der Mineralien ” each passed through foureditions, and only last year he gave an interesting essay on thehistorical development of the mineralogical sciences.1 He held aunique position as a leader, and he did more than anyone else inco-ordinating and stabilising crystallographic nomenclature andmethods. His name will for ever stand out as a landmark in thehis tory of crystallography .The deaths have also to be recorded of two distinguished mineralchemists, who both did valuable work, but on entirely differentlines.William Francis Hillebrand (1853-1925), as chemist onthe United States Geological Survey, had made many analyses ofminerals and rocks, including several rare and new minerals collectedby members of the survey in new country. The careful and detailedanalytical work for which he was noted led to the recognition ofseveral chemical elements not previously suspected to be presentin rocks. In 1888-1892 he made a number of very detailedanalyses of uraninite (pitchblende), in which he found a gas. This“ Entwicklungsgeschichte der mineralogischen Wissenschaften,” Berlin,L. J. Spencer, “ Biographical Notices of Mineralogists Recently Deceased ”1926.(third series), Min. Mag., 1927, 21, 229MJXERALOClICAL CHEMISTRY.293gas evidently puzzled him, and he concluded that it was mainlynitrogen. Sir William Ramsay afterwards, in 1895, identified it ashelium, and uraninite was the first known terrestrial source of thiselement. Hillebrand’s well-known book “ Analysis of Silicate andCarbonate Rocks” was first issued in 1907 as a Bulletin of theUnited States Geological Survey, and has passed through severaleditions. Working as a student in Heidelberg under Bunsen heprepared metallic cerium in 1875 and discovered its pyrophoricproperty, a property which now has an extensive practicalapplication.Gustav von Tschermak (1836-1927), of Vienna, died on May 4th,at the advanced age of ninety-one years. As distinct from the workof Hillebrand, his work consisted largely in correlating the largeamount of data accumulated by analytical chemists and in deducinggeneral principles.The current views of the text-books on theconstitution of many of the main groups of silicates are due to him,and were developed in a series of classical papers extending overmany years : plagioclase felsprs (1865), pyroxenes and amphiboles(1868), micas (1877), scapolites (1884), chlorites (l890), vermiculites(1891), tourmaline (1899), zeolites (1917-1918). In later years,with the help of his pupils (including his daughter Silvia Hillebrand),he endeavoured to determine the composition of silicic acids isolatedfrom natural silicates. The valuable periodical TschermahMineralogische und Petrographische Mitteilungen was commenced byhim in 1872, and his well-illustrated “ Lehrbuch der Mineralogie ’’passed through nine editions.Mineralogical jubilees are now falling due.That of the Miner-alogical Society of Great Britain and Ireland (instituted February3rd, 1876) was celebrated last year: and was attended by severaldistinguished foreign mineralogists. The Socihth frangaise deMinhralogie was founded on March 21st, 1878, and the fifty volumesof its Bulletin show a record of brilliant work. As noted above,Groth’s Zeitschrift and Tschermaks Mitteilungen were commencedin 1877 and 1872 respectively. The Russian Mineralogical Societydates from a much earlier period (1817), whilst those of Vienna(1901), Germany (1908), America (1919), and Switzerland (1924) arelater.Account of the jubilee celebration, Min.Mag., 1926, 21, 99-148. Refer-ence is there made to the earlier British Mineralogical Society (1799-1806),which consisted of a small group of chemists, including Arthur Aikin, whooffered to “ examine, free of expense, all specimens of earths or soils, witha view to determining the nature and proportions of their different contents.’That society led to the foundation of the Geological Society of London in1807294 ANNUAJi REPORTS ON THE PROGRESS OF CHEMISTRY.Geochemical Distribution, of the Elements.The series of elaborate papers under this title has been continuedby V. M. Goldschmidt,4 but in the later numbers the scope of theinvestigation has been gradually changing-dealing with X-raydeterminations of the crystal structure of the rare-earth oxides,the laws of crystal chemistry, etc.It is suggested that elementsshowing some homceomorphous relation between the crystal struc-ture of their compounds should be found in association in nature.However, work on the original lines has been continued by someof his collaborators. G. Lunde 5 has examined a variety of mineralsand basic igneous rocks from Norwegian localities for traces ofplatinum metals, finding 04000074% Pt in an olivine-rock and inhornblende-gabbro, and 0~000006% in tantalite. The wide dis-tribution of traces of iodine has been further investigated by T. vonFellenberg and G. Lunde.g In meteoric irons and stones, amountsof iodine up to 0~000018% have been detected, together with up toOW056% of bromine, the latter especially in the stones.Systematicsearch for such elements, which are widely distributed althoughnever found in concentrated quantities, is, of course, of someeconomic importance.Constitution of Silicates.A comparative study of mineral silicates with the more tractableorganic silicon compounds would no doubt throw some light on theconstitution of the former. Some comparisons of this kind weremade by the late J. Emerson Reynolds, and by the oxidation ofthe compound CaSi,Al, (analogous to CaC,N,) he synthesisedanorthite by an interesting method. A long series of valuablepapers by F. S. Kipping and his co-workers on organic derivativesof silicon has appeared in the Jourml of this Society since 1901.G.N. Ridley,’ in a brief outline of some of the present views on theconstitution of the silicates, has compared ethyl orthosilicate,Si( OC,H,),, with olivine, Mg,SiO,, and ethyl metasilicate,SiO(OC,H,),, with enstatite, MgSiO,. On similar lines, W. Wahlhas compared aluminosilicates with alumino-oxalates , tracing, itwould appear, a close analogy. He had recently proved8 thatcertain alkali aluminium trioxalates of the typeAI,(C,O4)3 3R1&&04 nH20 Y4 “ Geochemische Verteilungsgesetze der Elemente,” Nos. I-VIII, Viden-skapssel. Skrifter, Kristiania (later Skrifter Norske Videnskaps-Akad. Oslo),1923-7 ; compare Ann. Report, 1923, 20, 262.6 2. anorg. Chem., 1927,161, 1; A,, 439.6 Biochem. Z., 1926,175,162; A., 1926,1022; 1927,187,l; Beitr.Cfeophgsik,Chem. News, 1925,131, 305; A., 1925, ii, 1130.8 Ber., 1927, 60, [B], 399; A., 339.1927, 16, 413MINERALOGICAL CHEMISTRY. 295usually regarded as “double salts,” can be split up into opticaIZyactive enantiomorphous isomerides. It therefore becomes necessaryto write a co-ordination formula, witha central sexavalent (“ co-ordimtionnumber ” 6) aluminium atom, the six C20,an octahedron to form the tervalent anion.One of the nine possible types of alumino-oxalates is here shown with two aluminium atoms. In some othercases a central quadrivalent aluminium atom forms with two C,O,groups a univalent anion, giving the complex [C,O4:Alxv:C2O4]R1.The aluminosilicates are suggested9 to be analogous to these alumino-oxalates, and formule on the same lines are given for numerousminerals, a “ silicyl ” group, SiO,, or a “ bisilicyl” group, Si,O,,taking the place of the oxdato-group.Some of the formula?,e.g., for the micas, are written to show the polymerisation of themolecule, and these are so large and complex that they are given astext-figures. The following examples may be quoted :groups being arranged as at the corners ofA1IV :Si20Leucite, Orthoclase, GsI.net,[Al,(Si0,)41KZ* [A1,(SiO*)z(SizOs)*IK,. [AIzOa(SiOa )a ICaa.These formulze suggest an explanation for the breaking down oforthoclase into leucite and silica at a high temperature, for thealteration of felspar to kaolin, of garnet to chlorite, etc. Thealuminosilicates being all high-temperature compounds, suchformulze cannot be tested by the methods of stereochemistry, &E)in the case of organic compounds.They are essentially differentfrom the co-ordination formule proposed by J. Jakob.9aIt is further suggested10 that silicon is not always quadrivalentin the silicates. In the fluosilicates the silicon atom is surroundedby six fluorine atoms and the co-ordination formula is [SiVrE’6]R*2.If the fluorine is replaced by oxygen, the compound [Siv10,]R12,with the same empirical composition as a metasilicate, is obtained.This is assigned to clinoenstatite, which at a high temperaturebreaks down into forsterite and silica. A compound similar tothis, together with “ syntagmatite ” and an addition product ofW. Wahl, Finska Kemistsamfundets Meddelanden, 1927, Nos.1 & 2,40 pp.; 2. Krist., 1927, 66, 33, 173. * Helv. Chim. Acta, 1920, 3, 669; A., 1920, ii, 764; 2. Krist., 1921 56,296; see Ann. Report, 1923, 20, 266.lo W. Wahl, Ann. A d . Sci. Fennicae, Ser. A, 1927, 29, No. 22296 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.jadeite, would give molecules with sufficient structural similarityto form isomorphous mixtures, and so explain the presence ofaluminium in the amphiboles.CI inoenstctti te,[Si20,lMg2. of Tschermak.Addition productof jadeite.Here there is a replacement of silicon atoms with a co-ordinationnumber of 6 by aluminium atoms also with a co-ordination numberof 6. Such a replacement had indeed been suggested for thealuminous amphiboles by P.A. von Bonsdorff in 1821, but thiswas acceptable only before the current ideas of valency haddeveloped, and these, it seems, must now be modified.An interesting attempt to elucidate the constitution of the silicateshas been made by W. L. Bragg,11 who has attacked the problemfrom an entirely new point of view. From the results arrived a t bythe determination of crystal structures by X-ray methods, it issuggested that the structure of silicates is governed by the arrange-ment of the oxygen atoms. These are assumed to be the largestof all the atoms that enter into the composition of the silicates,and the diameter assigned to them is 2.7 8. A symmetrical arrange-ment of such atoms, according to either the cubic or the hexagonalplan of closest packing, is supposed to form the foundation of mostsilicate structures.The smaller atoms of silicon and of the con-stituent metals merely fall into the interspaces between the oxygenatoms. In most cases it appears that the silicon atoms lie at thecentre of a tetrahedral group of four oxygen atoms, as in the buildingunit assigned to g-quartz 12 and tridymite.13 In determining thestructure by X-ray methods of any particular mineral, an attemptis made to locate the precise position of each atom. The relativepositions of the several atoms will then give some idea of the chemicalconstitution.In 1920 W. L. Bragg,f* in a series of calculated atomic diameters,gave that of oxygen (1-30 8.) as the smallest of all the elements.To be told now that it is the largest of all is somewhat disconcerting.If oxygen is to play the governing part in the structure of the silicates,25, 302.406; A,, 1926, 13.11 PTOC.ROY. ~ o c . , 1927, [A], 114, 460; A,, 601; PTOC. Roy. Inat., 1927,12 (Sir) W. H. Bragg and R. E. Gibbs, Proc. Roy. SOC., 1925, [A], 109,18 R. E. Gibbs, ibid., 1926, [A], 113, 351; A,, 1927, 10.14 Ann. Report, 1920, 17, 201MINERALOGICAL CHEMISTRY. 297it should presumably also do so in the many other oxygen salts;and we might consequently argue that there would be only minordifferences in structure between CaSiO,, CaCO,, CaSO,, NaNO,, andNaClO,, or between ZrSiO,, CaSO,, AlPO,, KClO,, etc. As a.matter of fact, these are all very different, the only striking similaritybeing between CaCO, and NaNO,.Further, it is difficult toaccustom ourselves to the idea that silicon is not an essential andreally important constituent of the silicates. In many of theircharacters silicates are markedly different from other oxygensalts. They are, for example, usually distinguished by a highdegree of hardness,l5 as compared with the relatively soft car-bonates, sulphates, etc. The considerable difference in hardness(5 and 7 on Mohs's scale) in two directions on the same face of acrystal of kyanite presents a peculiar problem; and it must notbe forgotten that talc is the softest of minerals.V. M. Goldschmidt,lG on the other hand, points out similaritiesin crystal structure between Z%SiO, (willemite) and Li,BeF,, andbetween CaMgSi,O, (diopside) and NaLiBe,F,.These are evidentlyhomocomorphous relations depending on nearness of molecularvolume, as pointed out for many similar,cases by J. I). Dana in1850. In the same place V. M. Goldschmidt suggests that diopsideis the calcium salt of " diopside " acid, H,MgSi,O,, and jadeite thesodium salt of " jadeite " acid, HAlSi,O,. In another directionhe argues,l' from certain similarities in structure between Mg,SiO,(olivine) and K,SO, on the one hand and A1,BeO4 (chrysoberyl) onthe other, that the first is an orthosilicate. For the metasilicatesMgSiO, (enstatite) and CaSiO, (wollastonite) he finds no othercompounds ABX, of the same crystal type, and it is suggested thatMgSiO, is not a metasilicate, but may be Mg,SiO, + SiO,, and thatorthoclase, KAlSi,O,, may be KAlSiO, + 2Si0,.Crystallographic similarities, based on " comparative externalmorphology" as shown by the development of zones and crystalfaces, are used as a basis of classification by P.Niggli in the secondedition of his " Lehrbuch der Mineralogie " (vol. 2,1926). Here wefind silicates ranged with a variety of other minerals : e.g., phenacitewith cuprite, wollastonite with borax, kaolin with graphite, tour-maline with aragonite, etc. When the imagination is given fullplay, crystallography appears to open out endless possibilities.By the skilful manipulation of axial ratios and neglecting dis-crepancies corresponding with angles up to 74' (i.e., half the1 6 The relation between hardness and crystal structure has been diacuaaedby V.M. Goldschmidt, Skrifter Noreke Videmkaps-Akad., 1927 (for 1926),No. 8, p. 102.16 Ibid., p. 131. l7 Ibid., 1926, No. 1, p. 110.K 298 ANNU& REPORTS ON THE PROGRESS OF CHEMISTRY.difference between 30" and 45"), it is of course possible to demon-strate crystallographically any similarity that may be desired.18Helvine, as dark brown tetrahedra associated with fluorite andgarnet in pegmatite from a new occurrence in Argentina, has beenEtnalysed by W. Fischer,lg who also gives a full discussion of thevarious formula that have been proposed for this and the closelyallied minera1 danalite. This analysis [SiO,, 32.65 ; BeO, 12.20 ;MnO, 30-79; FeO, 14.75; ZnO, 4-89; MgO, 2.24; S, 6.01; total(less 0 for S), 100*54], in showing the presence of some zinc, indicatesa transition from helvine to danalite.When ignited in air themineral gains 3.18% in weight, and water then extracts iron andmanganese sulphates. The formula of helvine was formerlyexpressed as a double compound of the orthosilicate and mono-sulphide of the bivalent metals 3(Mn,Be,Fe),SiO4,(Mn,Be,Pe)S.Since, however, Be : (Mn,Fe) is in the constant ratio 3 : 4, the formula,is better written as3 (Mn,Fe)BeSiO,, (Mn,Fe)S or (Mn,Fe),Be,( SiO,),S,representing an isomorphous mixture of 3hlnBeSi04,MnS and3FeBeSi04,FeS. This formula was written by Brogger and Back-strom (1890) in the form (Mn,Fe)2(Mn,S)UBe,(Si04), in order toshow a relation to the garnet group R1',Rm2(SiO4),, where Be, takesthe place of AI,, etc.J. Jakob (1920) gave a co-ordination formula,which was modified by W. Fischer, the two being, respectively,(Moe,Zn), 0 0p e (Ofii0) , ] 2 and pe(SiO,),] (Fe,Mn)S *But, as pointed out by V. M. Goldschmidt,20 this formula correspondswith the ratios 1Be : 6(Mn,Fe) : 3Si : 120 : lS, whilst the analysesgive Be,(Mn,Fe),Si,012S.are very similar to those given by sodalite, and the unit cubes ofedges 8-19 and 8-85 8. contain two molecules, Be,Mn,Si,O,,S, andA16Na,Si6024C1, (sodalite), respectively. C. Gottfried?, however,finds only one such molecule of helvino in a unit cell of edge 8.52 8.Another mineral belonging to the same group and also crystallisingas regular tetrahedra is the zunyite from Zufiy mine, Colorado. Anew analysis 2, agrees very closely with the earlier analyses ofW.F. Hillebrand (1883) and S. L. Penfield (1893), from which thel* An example that has always acted personally as a warning in this direc-tion is that given by the comparison of the axial ratios of andorite(PbAgSb3S,), aeschynite, coluxnbite (FeNb,OJ, and chalcostibite (CuSbS,)(see Min. Mag., 1897, 11, 286; 1907, 14, 320).lS Bol. Ac&. Nac. Ciencias, Cbrdoba, 1926, 28, 133; Centr. Min., [A],1926, 33.I1 T. Barth, Norsk Gml. Tidsskr., 1926, 9, 40.z2 2. Krist., 1927, 65, 425.es B. Gossner and F. Mussgnug, Centr. Min., [A], 1926, 149.X-Ray powder photographs of helvine20 Centr. Min., [A], 1926, 148MINERALOCIICAL CHEMIS!CRY. 299empirical formula H18A1,,Si,( 0,F,Cl),5 was deduced by Hillebrand.This was modified by Brogger and Backstr8m asto correspond with the garnet formula.B. Gossner and F. Mussgnugdevised a formula, SiO,,AlF( OH),,2A102H or 2SiO2,2Al0F,3A10,H,in which SiO, is partly replaceable by A10,H or A1OF (as suggestedby the hommomorphism of TiO, and MgF,). Later,24 however, onthe ground of X-ray examination of the material analysed, theformula was adjusted so that six molecules3Si0,,3AZO(F,C1),4AlO2H,2Al( OH),shall be contained in the unit cube of edge 13.92 A. Surely thisis only leading to greater complexity, if not confusion.B. Gossner has also employed X-ray methods for the purpose ofdeducing the probable chemical formulae of some other complexsilicates, the formula being readjusted so as to give a whole numberof molecules in the unit cell.For example, for the mineral leifite(of 0. B. Barggild, 1915), as calculated from the original formulaNa2A12Sig0,,,2NaF (M = 788*5), the unit hexagonal cell of dimen-sions a = 14-34, c = 4.93 8. would contain 1-78 molecules. Adop-tion of a formula Na,Si,O,,AlOF (H = 359.5) gives 3433 moleculesin the unit cell, and this is considered a sufficiently close approxim-ation to 4 to justify the new formula.25An exhaustive discussion on the chemical composition of thenumerous minerals of the complex group of chlorites has beengiven by J. Orce1.26 After a detailed historical review of the varioustheories of their constitution, he comes to the conclusion that beforethese theories can be thoroughly tested more data must be accumu-lated. He therefore gives a series of new analyses, with density andoptical determinations, for nineteen chlorites belonging to varioustypes, including two new types-an aluminous sheridanite and amagnesian thuringite.These and earlier analyses (290 in number)are calculated to the ratios SiO,/R,O,, FeO/MgO, Fe,O,/Al,O,, andCr,O,/Al,O,, and only empirical formula are given. On thesoratios is based a new classification of the chlorites : I, Amesite, withSiO,/R,O, = s = 1. 11, Corundophyllite group, s = 1.33 to 1.66.111, Prochlorite group, s = 1-66 to 2.33. IV, Prochloriteclino-chlore group, s = 2.33 to 2-66. V, Clinochlore group, 8 = 2.66 to3.33. VI, Clinochlore-pennine group, s = 3.33 to 3-5. VII,Pennine group, s = 3.5 to 4.5. VIII, Chlorites poor in alumina,s>4*5.Each of these groups is sub-divided according to theratios FeO/MgO and Fe,O3/A&O3; but for the ratio Cr,O,/Al,O,[Al(oH,F,c1)2]~Al2(sio,),24 B. Goswer, Jahrb. Min. Bei1.-Bd., [A], 1926, 55, 319.86 B. Gossner and F. Mussgnug, Centr. Min., [A], 1927, 221.86 Bull. Soc. fraw. Min., 1927, 50, 75; ThAse, Paris, 1927, 380 pp.; A.,1923, ii, 647; 1924, ii, 621; 1926, ii, 821; A., 1926, 42, 933, 1119300 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.the chromiferous chlorites are treated in the text as a special group,IX. To fit this classification certain chlorites (aphrosiderite,thuringite, bavalite, daphnite, delessite, diabantite, leuchtenbergite,kotschubeite) have been re-defined, whilst other terms (rumpfitechloropite, protochlorite, dumasite, pseudophite) are regarded assuperfluous.Optical data are tabulated with the chemical ratiosgiven above, and it is shown that chlorites of different chemicalcomposition may differ in some cases only slightly optically (e.g.,grochanites, clinochlores, and prochlorites). Also dehydrationexperiments (time-heating curves and pressure of aqueous vapourwhen the mineral was heated in a vacuum) led to no definite results.Chlorites are usually thought to be secondary minerals, but theymay also occur as primary constituknts of igneous rocks.The work of H. S. Washington and H. E. Merwin on the chemicalcomposition and optical and other data of the pyroxenes and amphi-boles has been extended to the acmitic pyroxenes, 27 and valuabledata, all determined on the same sample of material, are recorded.They find that the molecules acmite (Ac = Na20,Fe203,4Si02),jadeite (Jd = Na2O,AI20,,4SiO2), vanadous acmite (Vac =Na,0,V20,,4Si02), diopside (Di = Ca0,Mg0,2Si02), and heden-bergite (Hd = Ca0,Fe0,2Si02) may mix in all proportions.Forexample, an “ acmitic diopsidic hedenbergite ” is represented bythe formula AclO,Jd6,Di17,Hd60,A7, where A represents the sumof such molecules as FeO,SiO, ; Fe203,3Si02 ; A120,,3Si02, etc.Excess of sesquioxides is assumed to be present as Rj20,,3Si0,,rather than in the molecules E”e0,Pe,03,4Si02 and Fe0,A1203,4Si02,or in solid solution uncombined with silica. Arfvedsonite fromGreenland has been the, subject of detailed determinations byS.G. Gordon.28 The analyses are interpreted as mixtures of thearfvedsonite molecule (R20,3R0,4Si02), riebeckite molecule(R,0,R20,,4Si0,), and usually an excess of R203, where R20 islargely Na20, and RO and R203 are chiefly FeO and Fe203respectively.Examination of Minerals by X-Ray Methods.The crystal structures of a large number of minerals have nowbeen determined by X-ray methods, and a considerable mass ofdata has been accumulated and in part tabulated.29 Unfortunately,t 7 Amer. Min., 1927, 12, 233.2s L. J. Spencer in “ Tables annuelles de constantes et donndes numdriques,”vol. 6 (for 1917-22), p. 1391, Pans, 1926; vol. 6 (for 1923-4), p. 1226,Paris, 1928. R. W. G. Wyckoff in “ International Critical Tables,” vol. 1,p. 338, Washington, 1926.And in greater detail by P. P. Ewald and C.HermaM, “ Strukturbericht, 1913-26,” issued as separately-paged supple-ments in 2. K~ist., 1927, 65 et seg.PTOC. Acad. Nat. Sci. Philadelphia, 1927, 79, 193MINERALOGICAL CHEMISTRY. 301however, these data have only rarely been correlated with constantsdetermined by other methods on the same sample of material.The majority of original papers give very little idea as to the kindof material that has been used in the experiments, and sometimesit is not clear whether artificially prepared material or a naturalmineral has been employed. Due attention does not seem to havebeen always paid to the careful selection of material, and in a fewcases even the identity of the mineral appears to be open to doubt.Most X-ray workers are content to quote the crystallographicdata and density, and even the chemical composition of the materialin hand, from P.Groth's " Chemische Krystallographie '' (5 vols.,1906-1919). This is a most useful standard work of referencefor the crystallographic constants of artificially prepared chemicalcompounds ; but for minerals it is admittedly incomplete, withonly a few of the more important references to the original literature,the idea being that the full information was already available inthe text-books on mineralogy. For example, under the heading" Berylliumaluminiummetasilicat = SisOleAlzBe3," Groth gives avery inadequate account of the mineral species beryl. There areseveral varieties of this mineral.Some contain up to 5% ofalkalis (usually czsium) and most contain up to 2% of water.The text-book formula of beryl can be regarded as only approxi-mate, and it may be doubted if the mineral is really a meta-silicate. The density of beryl is given by Groth as 24----2.7, butrecent determinations show a range from 2.545 to 2.910. Thehexagonal crystals, although well developed, sometimes show opticalanomalies and a complex intergrowth in sectors. Now, based onthis information taken from Groth, a most elaborate structure hasbeen built up for beryl as deduced from the examination of a crystal(or crystals 1 ) by X-ray methods.30 Not the slightest indication isgiven in the original paper of the kind of material used for thisinvestigation; there is no mention of colour (a useful guide to thevarieties of beryl), density, or other characters." The X-raymeasurements lead to a value 2.661 for the density "-but a directdetermination would have been more useful.The same authors31 have also, on data quoted from Groth,deduced structures to explain the morphotropic relations of thehumite group of m'inerals. This group has frequently been quotedas a classical example of a morphotropic series. These morpho-tropic relations are based on the chemical formulz of Penfield andHowe (1894), which have never been confirmed; and recently they30 W. L. Brrtgg and J. West, Proc. Roy. SOC., 1926, [A], 111, 691; A,,1926, 889.31 Idem, ibid., 1927, [A], 114, 450; A., 501302 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.have been called into question by G.Ce~iiro,~~ who has deducedother formulae from the original analyses. Further, H. Sjogren’s“ prolectite ” (1895), supposed to be an end member of this series,has been proved to have no existence.% The three mineralschondrodite, humite, and clinohumite are not easy of determinationand distinction, and it would not appear that the X-ray methodaffords a practical test.It is evident that in the examination of minerals exclusively bya single method, such as the X-ray method, a too narrow view isbeing taken. The same undue importance is often also attached tooptical methods in mineralogy. The only papers on minerals inwhich the materials have been completely examined by all availablemethods, including X-ray methods, are those by G.Aminoff. Forthe minerals br~mellite,~~ magnetoplumbite,35 swedenborgite,36 andtrimerite,37 the crystallographic constants, crystal structure, opticaldata, density, chemical composition, etc., have all been determinedon the same sample of material. The history, origin, and para-genesis of the minerals are concisely stated, and the main factsand data are clearly set out, for the benefit of the reader or recorder,without being confused with a mass of more or less irrelevantspeculation. Further, the papers are presented once for all in acompleted and finished form. There are no preliminary notices,reprints with minor modifications and corrections, and translationsin other journals. This simplifies the literature and the work ofthe bibliographer.These excellent papers may well be taken as apattern.Several minerals of the pyroxene group have been examined andcompared by the X-ray powder method; 38 and here in severalcases the work was done on material that had been previouslycompletely determined chemically and optically by the sameauthors. These minerals give patterns of four main types :(1) Diopside (including hedenbergite, acmite, jadeite, augite) ;(2) Enstatite (and hypersthene) ; (3) Wollastonite (and bustamite,pectolite, schizolite) ; (4) Rhodonite (and calcium-rich rhodonite).Some others (clinoenstatite, spodumene, alamosite, pyroxmangite,sobralite, babingtonite) give other types of pattern. It was foundthat the replacement of MgO by FeO produces practically no changeBull.Acad. TOY. Belg., 1926, 12, 350; A,, 1927, 336.33 P. Geijer, CTeol. P6r. P6rh., 1926, 48, 86.s4 2. Krist., 1925, 62, 113; Ann. Report, 1925, 22, 277.35 Qeol. F6r. FGrh., 1925, 47, 283.8 8 Ibid., 1926, 48, 19.37 2. Krkt., 1924, 60, 262; Ann. Report, 1925, 22, 279.38 R. W. G. Wyckoff, H. E. Merwin, and H. S. Washington, Amer. J . Sci.,1926 [v], 10, 383; A., 1926, ii, 1126MINERALOGICAL CHEMISTRY. 30 3in the structure; MnO has a slightly greater volume, and CaO anappreciably greater volume. In augite the excess of Al,O, andFe,O, has no appreciable effect.The unit-cell dimensions of the isomorphous members of thegarnet group have been determined by G. Menzer39 and also byC. H. Stock~ell.*~ The latter has determined for 40 garnets therefractive index, specific gravity, and the edge of the unit cube(by the X-ray powder method).In only two cases, however, werethe determinations made on analysed material; but with the aidof the previous work of W. E. Ford (1915) on the refractive indexand specific gravity of the garnets, a correlation was obtainedwith the chemical composition. Plotting refractive index againstspecific gravity, Ford found that the garnets fall into two series(almandine-pyrope-spessartine and grossular-andradite), and thisis emphasised by plots of the cell dimensions against either therefractive index or the specific gravity. From these data, (with,in some few cases, a supplementary qualitative test for manganese),Stockwell was able to determine the nature of a given garnet, andthe percentage molecular composition can be calculated.Thecalculated values for the pure molecules are :Pyrope, Mg,Al,(SiO,), ............... 1.705 3-610 11.430 A.Almandine Fe,Al,(SiO,),. ........... 1-830 4.260 11.493Spessartine, Mn,Al,(SiO,), ......... 1.800 4.180 11.668Grossular, Ca,Al,(SiO,), ............ 1.736 3.630 11.840Andradite, Ce,Fe,(SiO,), ............ 1.895 3.760 12.040A good example of how X-ray methods may come to the aid ofmineralogical description when ordinary crystallographic methodshave failed is given in the case of the new mineral aramay~ite,~~Ag(Sb,Bi)S,. Distinctly developed crystals are not available andfrom the cleavages it could only be concluded &hat the mineralwas perhaps tetragonal. Laue photographs, taken by (Miss) K.Yardley 42 through the perfect basal cleavage, showed an absenceof symmetry, and spectrometer and powder measurements provedthe mineral to be triclinic (pseudo-tetragonal).By these means thedimensions of the unit cell and the crystallographic constants werecompletely determined.So many workers are now engaged on X-ray research that itoften happens that the same mineral has been examined independ-ently several times. For example, the following determinations ofthe unit orthorhombic cell of baryte (BaSO,) show a very satisfactoryagreement.9%. d. a.3s Centr. Min., [A], 1926, 344; 1926, 343.40 Arner. Min., 1927, 12, 327.41 L. J. Spencer, Min. Mag., 1926, 21, 166; A., 1927, 226.42 Min.Mag., 1926, 21, 163; A,, 1927, 190304 ANNUA4L REPORTS ON THE PROGRESS OF CHEMISTRY.a. b. C.L. Pauling and P. H. Emmett 4 5 .................. 8.846 5.430 7.10R. W. G. Wyckoff and H. E. Merwin 46 ......... 8.89 5.45 7-17F. Rinne, H. Hentschel, and E. Schiebold 4 7 ... 8.88 5-45 7.15W. Basche and H. Mark 48 ........................ 8.85 5-45 7-14S. K. Allison 43 ....................................... 4.449 5.448 7.170 A.R. W. James a d W. A. Wood 44 ............... 8.852 5.430 7,132With one exception, all these authors agree in taking a doublevalue for the a-axis, and the axial ratios a : b : c, usually acceptedas 0.8152 : 1 : 1.3136, become 1.6304 : 1 : 1.3136. This means thatthe rarer prism n(120) becomes the unit prism instead of the prismparallel to the perfect cleavage, which by crystallographers isnaturally taken as a primitive form. The reason for the markeddifference in this case is not clear.In this connexion we arereminded of the well-known similarity between the crystal formsof baryte and sulphates, selenates, chromates, perchlorates, andpermanganates with the same type of formula, vix., PbSO,, BaSeO,,BaCr04, KClO,, -no4, etc. F. Rinne 49 has referred to these asisotypes of the baryte type, and he points out a remarkable relationbetween the interfacial angles of the crystals. In baryte the meanof the three angles (110) : (110) = 78" 22', (011) : (01T) = 74" 34',(102) : (T02) = 77" 43' is 76" 53'; and in all the other salts themean of the corresponding angles is, perhaps by a mere coincidence,also 76" 53'.This angle is near to that (77" 19') of the cubicpentagonal-dodecahedron (540), which in combination with thecube closely resembles the baryte habit. The fact that some ofthese salts change into a cubic modification a t a higher tem-perature is perhaps related to this approximation to cubic angles.Based on the above similarity, A. E. H. Tutton 50 has calculatedfrom the topic axes the dimensions of the unit cells of variousperchlorates.In contrast with the above example of close agreement obtainedindependently by X-ray workers in different countries, an examplemay be quoted of lack of agreement. For the indirect determin-ation of density from the structure of mercury telluride (butwhether on artificially prepared HgTe or on the mineral coloradoite43 Amer.J . Sci., 1924, [v], 8, 261 ; A., 1925, ii, 18.44 Mem. Mamhster Phil. SOC., 1925, 69, No. 5; Proc. Roy. SOC., 1925, [A],45 J . Amer. Chem. SOC., 1925, 47, 1026; A., 1925, ii, 485.46 Amer. J . Sci., 1925, [v], 9, 286; 2. Krist., 1925, 61, 452; A., 1925, ii,4 7 2. Krist., 1925, 61, 164.48 Ibid., 1926, 64, 1.49 Centr. Min., 1924, 161.60 Proc. Roy. SOC., 1926, [A], 111, 462; A,, 1926, 888.109, 598; A,, 1926, 13.485MINERALOGICAL CHEMISTRY. 305is not in all cases quite clear) the following values have beenobtained :d.W. Hartwig 61 ....................................... 8.026W. F. de Jong 62 .................................... 8-20W. Zachariasen 53 ....................................8-42Microscopic Examination of Opaque Minerals.The examination under the microscope of polished sections ofore-minerals by reflected light, following the methods of metal-lography, has been much developed during recent years. Thissubject, or rather method of investigation, has been called " mineral-ography " or " mineragraphy '' in America and " chalcography ''(Chalkographie) 54 in Germany. Text-books have been written byJ. Murdoch (New York, 1916), W. M. Davy and C. M. Farnham(New York, 1920), H. Schneiderhohn (Berlin, 1922), and R. W.van der Veen (The Hague, 1925), and a useful outline with detailedbibliography has been given by J. O r ~ e l . ~ ~ Various chemicalreagents are applied to the polished surfaces for the purpose ofdistinguishing one mineral from another.More recently, themethod has been extended by the use of polarised light, it beingpossible to distinguish between isotropic and anisotropic crystalsand to determine the directions of the principal axes of refringenceand of absorption. The method has been extensively applied inAmerica and Germany to the study of ores and ore-deposits. Inaddition to identifying the various minerals present in the ore,much can be learnt from their mutual relations and order ofdeposition.Various obscure and doubtful metallic minerals examined bythis method have been proved to be really mixtures, and the com-plex chemical formulae that have been applied to them are thusreadily explained. The formula of bornite has been usually givenas Cu3FeS3; but the mineral is frequently intergrown with chalco-pyrite, chalcosine, etc., and even well-developed crystals oftencontain a nucleus of chalcopyrite.Recent analyses made onmaterial proved microscopically to be homogeneous have giventhe formula C U ~ F ~ S , . ~ ~ In argentiferous galena it has been shown61 Sitzungsber. Preuss. Aka&. Wiss. Berlin, 1926, 79; A,, 1926, 664.62 2. Krist., 1926, 63, 466; A,, 1926, 996.63 Norsk Geol. Tidsskrift, 1926, 8, 302; also 2. physikal. Chem., 1926, 124,s4 The term chalcography has been in use in English since s t least the66 Bull. SOC. frarq. Min., 1926, 48 (for 1925), 272-361 ; Rev. Mdt., 1926,m J. Orcel, Bull. $oc.frmw. Min., 1926, 48 (for 1926), 340.277 ; A,, 1927, 96, where the value 8.123 is given.year 1661 for the art of engraving on copper.23, 637, 618306 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.that the silver is present as specks of tetrahedrite or argentite, orsometimes, in richer samples, as veinlets of ruby-silver.Theexamination of polished sections of the selenium ores from theHarz Mountains has led to the identification of umangite (Cu,Se,)in addition to the selenium minerals previously known from thislocality. In polarised light the umangite shows a strong pleo-chroism, from cherry-red to grey.57 The complex intergrowths ofarsenides and sulpharsenides of cobalt, nickel, and iron occurringa t Cobalt in Ontario have also been studied by this method.5*The two modifications of silver sulphide, the cubic argentite andthe orthorhombic acanthite, were found by H.Schneiderhohn 59 in1922 to be optically anisotropic and both presumably orthorhombic.Crystals of argentite show a complex lamellar structure and areevidently paramorphs after the high-temperature cubic modification,as is the case with leucite. The inversion temperature for silversulphide is 180". Similarly, cuprous sulphide is dimorphous asrepresented by orthorhombic crystals of the mineral chalcosineand by artificially prepared cubic crystals, the latter being stableabove 91". In the copper ores of Tsumeb in South-West Africa,Schneiderhohn found in 1920 that the chalcosine is of two kinds :(1) a more abundant form with a granular structure and presumablyof secondary formation ; (2) one showing a complex lamellar struc-ture with an octahedral arrangement, very similar to the structureshown by meteoric irons.The latter he concluded was the primaryore which had crystallised as the cubic modification a t a temperatureabove 91", and which on cooling passed over into the orthorhombicmodification. The presence of " lamellar argentite " or of " lamellarchalcosine " fixes two points (180" and 91') on the " geologicalthermometer " in any discussion on the origin of ore-deposits.These conclusions, arrived at by the metallographic method, onthe dirnorphous relations of the silver and cuprous sulphides, havesince been amply confirmed by the X-ray method when the materialswere examined a t different temperatures.60Forms of Calcium Carbonate.While " conchite " and " ktypeite " are evidently compact formsof aragonite, the artificially prepared vaterite is doubtless distinctfrom both calcite and aragonite, and it appears to be identical withthe p-CaCO, of Johnston, Merwin, and Williamson (Ann.Report,6' G. Frebold, Centr. Min., [A], 1927, 16, 196; J. Olsacher, ibid., p. 170.s8 E. Thomson, Univ. Toronto Studies, Geol. Ser., 1926, No. 20, 54.69 Arner. Min., 1927, 12, 210.3'. Rinne, 2. Krist., 1924, 60, 299; L. S. Ramsdell, Amer. Min., 1926,10, 281; R. C. Emmons, C. H. Stockwell, and R. H. B. Jones, ibid., 1926,11, 326; T. Barth, Centr. Nh., [A], 1926, 284MINERALOGICAL CHEMISTRY. 3071917, 14, 241). More recent.ly, Gibson, Wyckoff, and Merwin6lfind by the X-ray powder method that the spherulitic material, towhich the name " vaterite " has been applied, includes two forms :" vaterite A " prepared by the method of Johnston, Merwin, andWilliamson is spherulitic calcite ; whilst " vaterite B " (i.e., thetrue vaterite), obtained from colloidal calcium carbonate at 5" inthe presence of an excess of potassium carbonate, is p-CaCO,.The latter was obtained by Johnston, Merwin, and Williamson ashexagonal plates.F. Heide 62 finds that the gelatinous precipitategiven by solutions of N/2-potassium carbonate and 2N-calciumchloride a t 5" changes after l+-2 hours to minute (3-10 p)radially-fibrous spherulites of vaterite. Heated a t 100" in water,this is transformed into calcite, but the dry material is stlabJe upto 430-440". X-Ray powder photographs show a structuredifferent from that of both calcite and aragonite.The hexagonalcell of vaterite has dimensions a = 4.120, c = 8.556 8., and containstwo molecules of CaCO,; the calculated density is 2.645. Afterheating a t 430--440", the material shows the lines of calcite in theX-ray ph0tographs.6~At higher temperatures the rhombohedra1 calcite is the onlystable modification, but transformation into ct-CaC03 a t 970" underpressure in an atmosphere of carbon dioxide was recorded byH. E. Boeke in 1912. Such a transition point could, however, notbe found by F. H. Smyth and L. H. ad am^,^^ and they placed themelting point of calcite at 1339" under 779,000 mm. pressure.This has an important bearing on the question of the occurrenceof primary calcite in igneous rocks, the so-called magmatic calcite,about which there has recently been much discussion.Magmaticcarbonate rocks (" carbonatites ") were described by W. C. Bragger(1921) from the Fen district in Norway; and E. Schuster (1919)and R. Brauns (1919) have described calcite-pegmatite and calcite-syenite from the Laacher See district in Rheinland. This hasbeen disputed by N. L. B ~ w e n , ~ ~ who considers that such occur-rences represent secondary replacement of silicates, particularlyfelspars, by calcite. When limestone rocks are invaded by igneousmagmas, there appears no reason why calcium carbonate shouldnot be incorporated in the mass and melted.There is, for example,abundant evidence of this in the pegmatite veins and nephelinc-61 Amer. J . Sci., 1925, [v], 10, 325; A., 1925, ii, 1183.62 Centr. Min., 1924, 641.63 F. Heide, ibid., [A], 1925, 198.64 J . Amer. Chem. SOC., 1923, 45, 1167; A , , 1923, ii, 490.66 Amer. J . Sci., 1924, [v], 8, 1; Centr. Min., [A], 1926, 241; Amer. J.Sci., 1926, [v], 12, 499; and replies by R, Brauns, Cen,tr. Min., [A], 1926,1 and 245308 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.syenites of Canada. Some authors66 have further attempted toprove that such calcite shows peculiarities of structure markingits inversion from a-CaCO, as the temperature fell below 970°,this being taken as a point on the "geological thermometer," inthe same way that the change from @-quartz to ct-quartz67 fixesthe point 575".The distinction appears, however, to be basedmainly on lamellar twinning and optical anomalies, such as maybe produced artificially in calcite by pressure. The name elatolite 68has been applied to what is believed to have 'been ct-calciteleached out of tree-like cavities in the nepheline-syenites of theKola peninsula in Russian Lapland.The minerals hydroconite, hydrocalcite (trihydrocalcite, penta-hydrocalcite), and lublinite periodically come to be regarded asdoubtful minerals, because when re-examined on museum materialthey are found to be merely calcite. Hydrated calcium carbonate(CaCO,,GH,O) is stable only below 5", and in nature it is but rarelyobserved in the winter as a mould-like efflorescence on limestoneand chalk.To preserve such a mineral a refrigerator would berequired. In addition t o the he~ahydrate,~~ crystals of the penta-hydrate have also been prepared ; whilst a trihydrate, perhapsstable between 17" and 25", could not be isolated.70Determinative Tables.E. S. Fedorov's method of crystallo-chemical analysis (Ann.Report, 1923, 20, 289), on which great hopes were laid, has notcome into general use. The symbols he uses are not generallyintelligible, and the introduction to his volume " Das Krystall-reich " is so written that from the volume itself it is not possibleto understand his method. A. K. Boldyrev, in a pamphlet pub-lished by the Russian Academy of Sciences,71 explains doubtfulpassages in this introduction and gives supplementary explanationsfor the instruction of the reader. Boldyrev 72 has also published66 T.L. Walker and A. L. Parsons, Univ. Toronto Studies, Ceol. Ser., 1925,No. 20, 14; J. L. Gillson, Amer. Min., 1927, 12, 357.67 Unfortunately there is here some confusion in nomenclature : a-CaCO,or a-calcite is the high-temperature modification, whilst in quartz the high-temperature modification is denoted as &quartz and the low-temperaturemodification &s a-quartz.O 8 A. E. Fersman, 1922-3 ; Ann. Report, 1925, 22, 278.6 ) Ann. Report, 1923, 20, 277.70 J. Hume, J., 1925,127, 1036; A , , 1925, ii, 697; J. Hume and B. Topley,J., 1926, 2932; A., 1927, 12.7 1 " Kommentarien zum Werk von E. S. Fedorow : ' Das Krystallreich ' "[Russian with German r6sum61, Leningrad, 1926, 72 pp.[Min. Mag. (Abstr.),1927, 3, 3261.72. M6m. SOC. Russe Min., 1924, 53, 261 [Min. Mag. (Abstr.), 1926, 3, 1SS-JMINERALOUICAL CHEMISTRY. 309a criticism of the method in which he points out that there is somedifficulty in arriving at the correct complex-symbol. He hastherefore suggested and worked out in some detail another methodof “ crystallo-chemical analysis.” This method is based on inter-facial angles taken in conjunction with other characters. Some9000 substances have been entered on catalogue cards and sortedaccording to the angles in each crystal system. The cards givefor each substance : (1) a list of the common crystal forms in theorder of their importance, cleavage, twinning, etc.; (2) physicaland optical data ; (3) the important crystal angles. In the opticallyuniaxial systems the angles given are those to the basal plane, andin the remaining systems the angles t o the axial planes (fromwhich the latitude and longitude, p and 9, angles of two-circlegoniometry can be deduced if wanted). The method is explainedin the French resume, and sample cards are printed in German inthe Russian text. The data have been largely compiled fromP. Groth’s “ Chemische Krystallographie.” One of the examplesgiven for the orthorhombic system is “ orthorhombic tin ” (“ /%tin ”).If the cards had sorted out properly it would have been noticedthat this is identical with stannous ~ulphide.’~Determinative tables or keys of various kinds have long beenused in mineralogy.They have been based on obvious externalcharacters, such as lustre, colour, and streak, supplemented byhardness, specific gravity, system of crystallisation, optical charac-ters, etc. In one ingenious device a number of perforated sheetseach corresponding with a certain character are laid over a sheeton which are printed the names of minerals until at last the nameof the mineral wanted appears in the only opening left. Rule-of-thumb methods of this kind only lead to error, and any table orkey must be used with a certain amount of understanding andintelligence. The main use of a table is in suggesting what agiven mineral may or may not be, and then some special test mustbe applied. E. S. Larsen’s tables of optical data (Ann.Report,1923, 20, 290) are perhaps the most practical and useful that haveyet been devised for determinative purposes. A table of specificgravities may also be a useful aid for the identification of minerals.A recent table 74 gives a numerical list of 2277 determined valuescollected from the literature for the period 1910-1927; and analphabetical list of mineral names gives the minimum and maximumvalues recorded for each mineral.A useful table might be compiled from the data given by theunit -cell dimensions (in Angstrom units) of crystals as determined73 Compare Min. Mug., 1921, 19, 113.74 L. J. Spencer, Min. Mag., 1927, 21, 337310 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.by X-ray methods. In such a table, with a numerical arrangement,there would be a considerable differentiation of the various kindsof materials.The X-ray patterns given by the powder method ofvarious known minerals have already been used by several workersas standards for comparison for the purpose of identifying theminerals present in intimate mixtures (Ann. Report, 1923, 20, 282).A reference collection of the X-ray powder patterns of chemicallyanalysed samples of minerals has been commenced in the Depart-ment of Geology of the University of Wisconsin.75New Minerals.A considerable number of " new " minerals have been describedmore or less completely since the last Report. The following listis limited to those that appear to be distinctive and well established.The ten lists of new mineral names that have been published a tthe end of each volume of the Mineralogical Magazine since 1897include all names not recorded in Dana's " System of Mineralogy "(6th ed., 1892) and show a total of 1506 names.These are nowall collected together in a general index to the set of volumes.76Undoubtedly many more minerals remain to be discovered,although it is of course not to be expected that all known inorganiccompounds will be found in the native state. P. N. Chirvinsky,77in a note on the prediction of minerals by mineral synthesis, givesa list of 163 chemical elements and compounds that had beenprepared artificially before they were known as minerals. He alsogives statistical data of the new minerals described during the past20 years, and finds that silicates and phosphates predominate.The suggestive work of the late Baron A.de Schulten might beextended in this connexion. He prepared artificially a number ofminerals in a crystallised form and determined the crystallographicand physical constants for the pure compounds. He then proceededto prepare the analogous compounds in the same isomorphousseries. For example, having obtained crystals of artificial monetite,CaHPO,, he then prepared the corresponding compounds in whichstrontium, barium, or lead takes the place of calcium, and arsenicthe place of phosphorus. I n this series he determined the crystal-lographic constants and optical data for CaHPO,, SrHPO,, BaHPO,,PbHPO,, SrHAsO,, and PbHAsO,. Crystals of CaHAsOp werealso obtained but they were too small for measurement. Any ofthese compounds might be expected to occur in nature, but hitherto76 A.N. Winchell, " ' Finger Prints ' of Minerals," Amer. Min., 1927, 12,261.76 L. J. Spencer, Min. Mag., 1926, General Index to vols. 11-20 (1896-1925).?7 P. Tschirwinsky, 2. KT~s~., 1926, 64, 644MINERALOGICAL CHEMISTRY. 311only monetite has been known. Recently his " arsenical leadmonetite " has been found as a mineral and named schultenite(p. 313 below).Two recently found minerals, not yet completely described,appear to represent new compounds of palladium. One of them,of sparing occurrence in the diamond washings of British Guiana,was determined by the late Sir John Harrison 78 to be a palladiummercuride with the probable formula PdHg.The small silver-white nuggets and grains have a density up to 15.82, i.e., consider-ably higher than that of either palladium or mercury. This mineralhas since been named potarite, from the Potaro River in BritishGuiana. A palladium antimonide,79 Pd,Sb, has been found, inassociation with fine large crystals of sperrylite (PtAs,), in thePotgietersrust platinum fields, Transvaal, where minute silver-white grains were detected in pannings of the platinum ore.Ammoniojarosite 81 is one of the few minerals containing ammon-ium and is interesting in illustrating the wide range of isomorphousreplacement in the jarosite group.Jarosite ....................................... K20,3Fe20s,4S0,,6H20Natrojarosite .................................Na20,3Fe,0,,4S0,,6H20Plumbojarosite ........................... Pb0,3Fe20,,4S0,,6H,0Argentojarosite .............................. Ag20,3Fe,0s,4S0,,6H20Ammoniojarosite ........................ ( NH4)20,3Fe203,4S0,,6H20Ammoniojarosite was found as small ochre-yellow nodules withtschermigite (ammonium alum) in lignitic shale; and, like allthe other members of the group, it comes from Utah. Stillanother member of the same group is probably carphosiderite,H20,3Pe2O3,4S0,,6H2O. Replacing ferric oxide by alumina,another section of this isomorphous group is represented by aluniteand natroalunite. Further, the sulphate may be partly or whollyreplaced by phosphate, giving several sulphato-phosphates (beud-antite, svanbcrgite, etc.) and phosphates (hamlinite, florencite,etc.), all of which are closely related crystallographically to jarositeand alunite.Aramyoite, 82 sulphantimonite and sulphobismuthite of silver,Ag(Sb,Bi)S,, is found in a silver-tin vein in Bolivia as iron-blackplaty aggregates with brilliant metallic lustre on the perfect basalcleavage.It breaks up into square (or nearly square) platesJ. B. Harrison and C. L. C. Bourne, OJ'. Gazette Brit. Uuiana, Feb. 27,1925, No. 71 ; A . , 1926, ii, 693.?@ H. R. Adam, J . Chem. Met. SOC. S. Africa, 1927, 27, 249; A., 861.*O L. J. Spencer, Min. Mag., 1926, 21, 94.89 L. J. Spencer, Min. Mag., 1926, 21, 156; A,, 1927, 226; E. Kittl,E. V. Shannon, Amer. Min., 1927, 12, 424.Revista Minera de Bolivia, 1927, 2, 53312 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.bounded a t the sides by fibrous pyramidal cleavages.In theabsence of definite crystal faces for goniometric measurement, itappeared to be tetragonal, but as determined by X-ray methods 83it is shown to be triclinic (pseudo-tetragonal), and the crystallo-graphic constants have been completely determined.Avogadrite, potassium fluoborate, KBF4, occurs as minute ortho-rhombic plates (homeomorphous with baryte, BaSO,, KMn04,and KCIO,) in saline sublimations from the floor of the crater ofVesuvius. The detection 84 spectroscopically of notable amountsof cmium together with potassium in the aqueous extract of thesesublimations led to the discovery of the new mineral, and itscharacters were more completely determined on material recrystal-lised from this solution.85 A comparison of the data so obtainedwith the physical constants of pure potassium fluoborate and ofpure casium fluoborate suggested that the crystals of avogadritecontained KBF,, 90.5yo, and CsBF4, 96y0.A later crop of re-crystallised material gave data (d 2.498, nsa 1.325) agreeing moreclosely with those for pure potassium fluoborate.86 The refractiveindex is less than that of water.B~ltgenbachite,~~ a complex copper salt,2CuC12,Cu(N03),, ~~CU(OH)~,~H,O,differs from connellite [2CuC1,,CuS04,15Cu(OH),,4H,0] in contain-ing nitrate in place of sulphate. It is found as a fine felt of sky-blue needles with native silver in cavities in cuprite a t Likasi,Belgian Congo.The crystals are hexagonal, and buttgenbachiteis optically negative, whilst connellite is positive. The two mineralsare the end members of an isomorphous series in which mixedcrystals occur; previously, W. E. Ford and W. M. Bradley, in1915, had found o.72y0 of N,O, in connellite from Arizona.FZuoborite,88 a fluoborate of magnesium, 3Mg0,B203+ 3Mg(F,OH),,has been found as colourless hexagonal prisms in an iron mine a tNorberg, Sweden.IanthiniteYs9 hydrated uranous oxide, 2U0,,7H20 ( ?), represent-ing an intermediate alteration product of pitchblende at the Kasolo83 (Miss) K. Yardley, Min. Mag., 1926, 21, 163 ; A,, 1927, 190.84 F. Zrwnbonini and L. Coniglio, Atti (Rend.) R. Accud. Lincei, 1926, [vi],86 C. Carobbi, ibid., 4, 382; A,, 1927, 129.87 A.Schoep, Compt. rend., 1925, 181, 421; Bull. SOC. chim. Belg., 1926,34, 313; A . , 1925, ii, 1196; H. Buttgenbach, Ann. SOC. gkol. Belg., 1926, 50,Bull. 35; A. Schoep, ibid., 1927, 49 (for 1926), Bull. 308; 1927, 50 (for88 P. Geijer, Geol. F6r. F'cirh., 1926, 48, 84 ; Arsbok Sveriges Geol. Unders.,8s A. Schoep, Natuurwetensch. Tijds., 1926, 7 (for 1925), 97; ibid., 1927,3, 521; A., 1926, 816. 86 F. Zambonini, ibid., p. 644; A., 1926, 934.1926-7), Bull. 216.1927, 20 (for 1926), No. 4.9, 1; Ann. SOC. gdol. Belg., 1927, 49 (for l926), Bull. 188, 310MINERALOGICAL CHEMISTRY. 313mine, Katanga, Belgian Congo, forms minute orthorhombic crystalswith a micaceous cleavage in one direction. The crystals areblack with a violet tinge and semi-metallic lustre ; the pleochroismis intense-dark violet to colourless. Some of the crystals arebordered by a yellow zone and others are completely changed to ayellow material. A crystal of ianthinite heated a t 50" in a drop ofwater changes from violet to brown and finally to yellow. Theseyellow alteration products are perhaps becquerelite and schoepite(U0,,2H20), although they differ from these in their optical char-acters. The refractive indices of ianthinite are wa = 1.674, n;e =1.90, n, = 1.92. A specimen acquired in 1922 for the mineralcollection of the British Museum has since been identified asianthinite. It shows a velvet-like pile of minute needles on pitch-blende. When acquired, the colour was purple, but now (1927) itis greenish-yellow; crystals that had been mounted in Canadabalsam still retain their original colour and intense pleochroism.The change is evidently due to oxidation in the air of a hydrateduranous oxide to a hydrated uranic oxide.Kernite 91 is hydrated sodium borate, Na2B40,,4H20, containingless water of crystallisation than borax. As large orthorhombiccrystals and as clear cleavage masses, it has been found in somequantity in bore-holes in Kern Co., California.MaZk~Zrite,~~ sodium fluosilicate, Na2SiF,, occurs as minutehexagonal prisms, together with hieratite (K,SiF,) in materialcollected from fumaroles on Vesuvius. The recrystallised materialshows regular growths of the cubic potassium salt on the hexagonalsodium salt. Another fluosilicate, cryptohalite [ (NH,),SB',], hadbeen previously observed on Vesuvius.Sch~Ztenite,~~ lead hydrogen arsenate, PbHAsO,, colourless mono-clinic crystals of platy habit, is found on pseudomorphous crustsafter mimetite and anglesite a t Tsumeb, South-West Africa. Thetable of angles for the several crystal forms is set out to give theangle from each face to the three axial planes, this method com-bining the advantages of both the arrangement of interfacial anglesin zones and the latitude and longitude angles of two-circleg~niornetry.~~?L. J. SPENCER.90 V. Billiet, Natuurwetemch. Pijds., 1926, 7 (for 1925), 112; Bull. Soc.91 W. T. Schaller, Amer. Min., 1927,12, 24; H. S. Gale, Engin. Mining J.,92 F. Zambonini and G. Carobbi, Atti (Rend.) R. Accad. Lincei, 1926, [vi],g3 L. J. Spencer, Nature, 1926,118, 411 ; A., 1926, 1022; Min. Mag., 1926,fraw. Min., 1926, 49, 136.1927, 123, 10.4, 171; A., 1926, 1119.21, 149; A., 1927, 226. s p Compare A. K. Boldyrev, p. 309 above

ISSN:0365-6217    

DOI:10.1039/AR9272400292

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

CHEMICAL KINETICS.ALTHOUGH in extent the subject of chemical kinetics is expandingalmost to constitute a separate and specialised branch of science,its general interest, so far from contracting in proportion, is widen-ing. Indeed its central problem, the interpretation in physicallyintelligible terms of the inner mechanism of chemical reaction, isperhaps that which presents the greatest common measure ofinterest to physicists and to chemists. Since the early days, whenthe mystery of slow chemical changes first began to attract atten-tion, many lines of advance have been opened, and it is ratherstriking to observe how practically all of these are still being activelyfollowed. First, there was the quantitative expression of reactionvelocities in terms of the law of mass action, and the analysis ofstoicheiometric equations into their component parts ; the correctrepresentation of reaction velocities in solutions where concen-trations and “activities” differ is the modern development of theformal side of this, and the discussions which still continue aboutthe equations expressing the velocity of such common reactionsas the union of hydrogen and chlorine show how far the work ofvan ’t Hoff is from completion.Then came the explanation of theremarkable effect of temperature on chemical reaction velocity,the introduction of the idea that only molecules with a certaincritical energy can react, and the application of the kinetic theory;all this started with Arrhenius many years ago, and is only nowreaching its full development.The drawing of a clear distinctionbetween homogeneous and heterogeneous reactions was an essentialstep forward. It was followed by the recognition of the fact thatthe law of mass action has to be applied in a quite different wayto heterogeneous reactions ; the development of the adsorptiontheory and its application to the kinetics of surface reactions stillproceed rapidly, and attention has lately been directed to the finerpoints about such reactions, e.g. their relation to the correspondinghomogeneous reactions, and the nature of catalytic surfaces. Van ’tHoff found long ago that many gas reactions take place only incontact with the walls of the containing vessel. This led to thebelief that no homogeneous gas reactions exist.It is now recognisedthat they exist, but are comparatively rare. The discovery of newexamples continues to be the object of many researches. Thusthere is a remarkable historical continuity about most of the aspectsof the subjectCHEMICAL KINETICS. 315The phenomena of chemical change are extraordinarily diverse ;and the last few years have seen many theories, perfectly valid forone set of facts, mistakenly applied beyond their proper scope.Their failure when thus misapplied has not infrequently led to anunduly agnostic attitude towards all attempts at theoretical explan-ation. Three theories, for example, have been proposed about themechanism of unimolecular reactions, and the suggestion and dis-cussion of each was a definite advance.Two of them appear notto be applicable, and this has caused them to be regarded, in somequarters, as valueless. This judgment, however, is mistaken in itsturn, since the ideas contained in each have provided the explanationof quite different classes of reaction.The phenomena of chemical change are not only diverse but alsocomplex. A result of this is that some of the most important lawsare to be distinguished, through a mass of minor complications, astendencies only. They are not the less important for lack ofquantitative exactness; but they can only be recognised by aclear-sighted consideration of the facts as a whole, and recognitionis not always immediate. A most striking example of this is tobe found in the history of Einstein’s law.The special sections of this Report deal as far as possible withsubjects in which definitely clearer views have emerged from thework and discussions of the last year or two.Thus only relatedgroups of investigations have been dealt with. This explains theomission of references to papers which, howcver important inthemselves, are of more specialised interest.Ionisation and Chemical Action.Since the nature of chemical combination ,is electrical, it islegitimate to inquire whether there is any general and fundamentalconnexion between chemical reactions and ionisation processes.Ever since the early days of the electron theory experiments totest this have been made from time t o time and there is now anaccumulation of evidence that any ionisation accompanying ordinarychemical reactions is of a secondary nature.J.J. Thomson originally suggested that flames were propagatedby the emission of electrons from the parts already burning, butextremely few or no ions could be detected in the combination ofhydrogen and chlorine (Thornson), the decomposition of ammonia(Kirkby and Marsh), the combination of carbon monoxide andoxygen (de Muynck), or the combination of hydrogen and oxygen(Haselfoot and Kirkby). Attempts have been made to stop orslow down the propagation of explosions by removing electronswith an electric field (Lind) or with a magnetic field (Dixon, Camp316 ANNUAL REPORTS ON THE PROGRESS OB CHEMISTRY.bell, and Slater), but with negative results. Malinowski, however,working with feebly explosive mixtures of certain hydrocarbonsand air, thought he could suppress the explosion in this way.A.K. Brewer,l using a much more delicate experimentaltechnique, succeeded in measuring the ionisation accompanyinga number of reactions, the interaction of nitric oxide and oxygenand of nitric oxide and ozone, and the decomposition of ozone,nitrogen peroxide, and nitrogen pentoxide. One pair of ions wasalways formed for the reaction of about 1013 molecules. Althoughthe ionic current was always proportional to the applied voltage,showing that a good deal of recombination occurred, this proportionis so small as to leave little doubt that the ionisation is of a secondarycharacter. W. E. Garner and S. W. Saunders2 found that thesmall ionisation produced in the explosion of hydrogen and oxygenwas more or less what might be expected for the purely thermalionisation at the maximum temperature of the explosion as calcul-ated from Saha’s equation.S. W. Saunders and K. Sato 3 measuredthe conductivity of exploding mixtures of carbon monoxide andoxygen, and Saunders4 of mixtures of acetylene and oxygen, andof methane and oxygen; the results all indicate that the ionisationis mainly thermal.The ionisation produced by burning bodies and by the escape ofgases from liquids has long been recognised as thermal or mechanicalin origin. (The accepted explanation of the ionisation accompany-ing the oxidation of phosphorus as due to an indirect photoelectriceffect has, however, recently been questioned by W.B ~ s s e . ~ )The only established example where there is any copious ionisationaccompanying a chemical change is the curious reaction betweenthe liquid alloy of sodium and potassium and gases such as carbonylchloride. Recent experiments of 0. W. Richardson and M.Brotherton6 confirm the view that we have here a unique case ofdirect chemical ionisation.There is nothing very puzzling about all these results i f we reflectthat in chemical reactions between substances not already ionisedthere is a re-arrangement of the electronic orbits constituting someof the non-polar links in the molecules. While there is no necessityfor any electrons to be detached in this process, a few may, inexceptional circumstances, escape, giving rise to the minute ionis-References1 J .Amer. Chem. SOC., 1924, 46, 1403; A., 1924, ii, 745.3 Tram. Paraday SOC., 1926, 22, 342; A,, 1926, 654, 1205.t o emly work are to be found here.Ibid., 1927, 23, 248; A., 605.Ibid., p. 256; A., 605.Proc. Roy. SOC., 1927, [A], 115, 20; A., 713.ti Ann. Physilc, 1927, [iv], 82, 873; A., 633WEMICAL KINETICS. 317ation observed in experiments such as those of Brewer. In Richard-son’s experiments, it is presumably the free electrons of the metalwhich escape.We conclude, then, that, in general, chemical change is in noway dependent upon, or necessarily accompanied by anythingmore than a small ionisation of a secondary or accidental character.*On the other hand, if fast-moving ions or electrons are intro-duced into or produced in a gas, marked chemical effects may bebrought about by their collision with other molecules. A gooddeal of work has lately been done on this subject.S.S. Joshi 7 has investigated the decomposition of nitrous oxidein the silent electric discharge (6000-12,500 volts; 150 cycles persecond) in respect of the influence of gas pressure and current;E. Warburg and W. Rump 8 have studied the formation of ammoniafrom its elements in a Siemens tube-though this appears to belargely a catalytic reaction. G. A. Elliott, S. S. Joshi, and R. WLunt 9 have worked out expressions for the velocity of a reactionin the silent discharge, assuming that transformation takes placewhen a gas molecule collides with an ion the kinetic energy ofwhich exceeds a certain critical value. W.K. Hutchison andC. N. Hinshelwood lo find that ammonia is 5 to 7 times as stablein an electric discharge as nitrous oxide, a fact which is parallelwith the greater stability of ammonia to the ordinary molecularimpacts which cause the thermal decomposition. G. I. Finchand I;. G. Cowen l1 find that for electrolytic gas up to a pressureof 180 mm. there is an inverse proportionality between the pressureand the minimum direct current required to ignite the mixture ina discharge tube. From this they conclude that ignition is deter-mined by the attainment in some portion of the gas of a definiteIn a well-known experiment of H. B. Baker’s, a silver wire is heated to its meltingpoint in an initially dry mixture of hydrogen and oxygen.Rapid combin-ation takes place a t the surface of the wire but visible drops of water areformed without any explosion in the bulk of the gas. For many years acomplete misinterpretation of this experiment has been current in certaintext-books, which state that no explosion occurs because the water formedin the experiment is pure and non-conducting. The experiment is supposedto prove some kind of pseudo-electrolytic or “ three-body ” theory of chemicalcombination. As we are dealing with ionisation and chemical change, atten-tion may be called to the fact that H. B. Dixon in his Presidential Address tothe Chemical Society in 1910 (J., 97, 661) gave the real explanation, which ismerely that, by the time drops of water are formed, the wire is surroundedby steam, and there is hardly any hydrogen and oxygen left to explode.* This is a convenient place for an historical observation.Trans.Paraday SOC., 1927, 23, 227; A., 635.Trans. Paraday SOC., 1927, 23, 5 7 ; A., 212.lo Proc. Roy. Soc., 1927, [A], 117, 131.* 2. Physik, 1926, 40, 557; A., 1927, 215.l1 lbid., 116, 529; A., 1146318 ANNUAL REPORTS ON THE PROGRESS ow CHEMISTRY.concentration of ions, and make the generalisation, which scarcelyseems justified, that flame propagation is essentially an electricalphenomenon. H. F. Coward and E. G. Meiter,12 studying theignition of methane by spark discharges, conclude that the sparkacts simply as a source of thermal energy.A.L. Hughes and A. M. Skellett l3 have studied the rate ofproduction of atomic hydrogen by electrons of energy considerablygreater than the critical dissociation value. The rate is directlyproportional to the pressure, whence they conclude that dissoci-ation depends upon a simple collision between an electron and amolecule. The combination of nitrogen and hydrogen under theinfluence of thermions has been measured by A. Caress and E. K.Rideal,14 who suggest that reaction may occur in several differentways, catalytically, and through the agency of hydrogen ions,ionised nitrogen molecules, and atoms, produced respectively atsuccessively increased voltages.Experiments of a rather different kind have been made byE. Rabinomitsch l5 who attempted to decompose solid metallicoxides by the impact of electrons.He finds that electrons with1000 times the velocity corresponding to the heat of formation ofthe oxides have an efficiency of the order of only one in 400 indecomposing the oxides.Having considered reactions in the gaseous and solid states, wecome to catalytic surface reactions. N. R. Dhar, in a theoreticalpa,per,lG revives the idea that in the adsorption of gases by solidcatalysts, ions and electrons are produced and are the active chemicalagents. G. T. Finch and J. C. Stimson,17 following up some earlierwork of H. Hartley,lB have examined the electric charge impartedto metal surfaces by gases. They measured the time-charge andtemperature-charge curves for H,, O,, CO, CO,, H,O, and for themixtures 2H2 + 0, and 2CO + 0, in contact with silver and goldup to 850".One of the most interesting results is that a t highertemperatures the curves for steam and for carbon dioxide are thesame as those for 2H, + 0, and for 2CO + 0,, respectively, indicat-ing that there is dissociation of water and of carbon dioxide on thesurface. The charged molecules on the surface are referred to as'' active " molecules, but it is very much to be doubted whetherthey have any connexion with chemically active molecules. Thel2 J. Arner. Chem. SOC., 1927, 49, 396; A., 318.l3 Physical Rev., 1927, [ii], 30, 11; A., 811.l4 Proc. Roy. Soc., 1927, [A], 115, 684; A., 943.lii 2. Elektrochem., 1927, 33, 186; A., 708.16 2. anorg. Chem., 1926, 159, 103; A., 1927, 216.l7 Proc.Roy. SOC., 1927, [A], 116, 379; A,, 1136.I* Ibid., 1914, [A], 90, 61; A., 1914, ii, 330CHEMIOAL KINETICS. 319magnitude of the charge is independent of the gas pressure for allthe gases ; this is very different from the reaction-velocity relation-ships. The results are interesting but it is probable that theirrelation to catalytic phenomena will be found to be a very complexone.Reproducibility of Reaction Rates : InJluence of Moisture andOther Impurities.Examples are known of chemical and physical effects which areonly produced in the presence of a trace of “impurity.” Theglowing of active nitrogen is apparently a phenomenon of thiskind.19 The stability of hydrogen peroxide in aqueous solution isvery variable, and F.0. Rice and M. L. Kilpatrick 2O have recentlyexplained this by showing that under ordinary circumstances therate of decomposition is mainly determined by the catalytic action ofdust particles. The rate of corrosion of metals is extremely sensitiveto impurities. Facts like these make it legitimate to raise thequestion whether chemical reaction velocities in general have anyabsolute significance. Several considerations, however, show thatmore often than not they have. First, it is quite easy to ascertainwhether the reaction velocity in any given example is reproducibleor not, and the lack of reproducibility which would indicate depend-ence on traces of impurity is very far from being the general rule.Secondly, the rates of certain reactions calculated theoretically arenot only in too close agreement absolutely with the experimentallyobserved values, but these values exhibit too coherent a relation-ship among themselves to leave much probability in the hypothesisof accidental catalysis.It is really a matter of the greatest ease for an experimenter todecide whether he is dealing with a reaction of the “ reproducible ”or of the “non-reproducible” class, but perhaps not quite easyto convince those who are not in direct experimental contact withthe matter.Fortunately, therefore, one of the most discussedreactions of recent years, the decomposition of nitrogen pentoxide,has been investigated under a great variety of circumstances by in-vestigators in different parts of the world, and it is now possible tocompare their results.H. S. Hirst21 found a velocity coefficientof 7.11 x lo3 at 35.4, compared with the value 7-71 xcalculated for this temperature from the data of 3’. Daniels and1* K. F. Bonhoeffer and G. KRminnky, 2. physikal. Chem., 1927, 127, 386;4o J . Physical Chem., 1927, 31, 1607; A,, 1164.11 J., 1926, 127, 657; A., 1926, ii, 664.A., 801320 ~ N U B L REPORTS ON THE PROQRESS OF CHEMISTRY.E. H. Johnston.22 The results of E. C. White and R. C. Tolman 23can be compared with those of Daniels and Johnston over a rangeof temperatures :Ic X 10, (W. & T.) ...... 103 219 837 1480k x lo6 (D. & J.) ......... 117 203 808 1510More recently a very complete study of the matter has been madeby F. 0.Rice and D. M. get^.^^ At 65", they find E = 0.286, com-pared with the value 0-292 of Daniels and Johnston. In order totest the possibility that the reaction might, depend on catalysis bydust, they compared the velocity coefficientpa for filtered and un-filtered nitrogen pentoxide and for gas which had been passedthrough an electrical dust precipitator. In some experiments thegas was dried with phosphorus pentoxide, in others not. Since allprevious workers had prepared the nitrogen pentoxide by thedehydration of nitric acid with phosphorus pentoxide, and sincethe gas might therefore always have contained the same impurityin the same amount-although this supposition is unlikely enough-they also used nitrogen pentoxide prepared by the action ofchlorine on silver nitrate.Finally they showed that there was noevidence of any catalytic effect of nitric acid on the decomposition.The principal results of these experiments are illustrated by thetable given below, all data referring to 65" :" Ordinary runs ........................................................... 0.286Gas filtered through blue asbestos .................................... 0.284Gas passed through electrical precipitator ........................... 0.278P,O, in reaction vessel ................................................... 0-278N,O, made from AgNO, and chlorine ................................. 0.291Last year, doubt was cast upon the validity of Bodenstein'sclassical work on the bimolecular gas reactions involved in theformation and decomposition of hydrogen iodide.B. Lewis andE. K. Rideal25 stated that when hydrogen iodide decomposed inpresence of phosphorus pentoxide, it gave, not the equilibriummixture, but hydrogen and iodine corresponding to completedecomposition. This was taken to prove that drying inhibitedthe union of the elements but not the dissociation of the com-pound. If this were correct, Bodenstein's measurements of therate of union would lose any absolute significance, and, incidentally,the second law of thermodynamics would be untrue. M. Boden-stein and W. Jost,26 however, point out that the results are entirelyTemp. 20" 25O 36" 40'k.zp J . Amer. Chem. Soc., 1921, 43, 53; A., 1921, ii, 249.23 Ibid., 1925, 47, 1240; A., 1926, ii, 682.2p J .Physical Chem., 1927, 31, 1672.26 J . Amer. Chem. SOC., 1926, 48, 2553; A., 1926, 1111.2 s Ibid., 1927 ,49, 1416; A., 737CHEMIOAL KZNE’MCS. 32 1accounted for by chemical reaction between the phosphorus pentosideand the heated gases.The thermal decomposition of ozone is an important reactionabout which our knowledge at the moment is not as certain asmight be desired, and there is some discrepancy between the resultsof different observers. The inhibiting effect of oxygen, originallyfound by Jahn and not found by Chapman and Jones, is now foundagain by 0. R. Wulf and R. C. Tolman,27 who suggest that theoxygen of Chapman and Jones contained a catalyst which counter-balanced the effect of the oxygen itself. They find a certain vari-ation in the velocity coefficients for different samples of gas, notso great, however, as to prevent them from inferring what is prob-ably the true value from a consideration of all their results.Itmust not be forgotten that this reaction, although predominantlyhomogeneous, is on the verge of being heterogeneous; and indeed,with certain kinds of glass the wall-reaction predominates. It isstill not quite clear that some of the difficulties do not arise fromthis cause.Discussion still continues about the necessity for moisture inchemical change, but there is no longer any general belief in it asa “universal catalyst.” The view is spreading that the mostcommon cause of inhibition by drying is the removal of a catalytic-ally active film of moisture from a boundary surface in a reactionbetween two phases, or from the wall of the containing vessel ingaseous reactions such as the combination of ethylene and bromine.28It is probable that the union of ammonia and hydrogen chloride isa surface reaction, catalysed by glass covered with a layer ofadsorbed water molecules.29 In these circumstances the influenceof the first trace and the ineffectiveness of additional amounts ofwater are readily understandable.Other polar substances wouldhave almost certainly the same effect as water, the r6le of whichis most probably not unique. Nearly all the examples of inhibitionby drying, which have been collected during the last few decades,are heterogeneous reactions of one kind or another. The onlyhomogeneous reactions, apart from explosions, which have beenstated to be retarded by drying are those between nitric oxide andoxygen and between hydrogen and chlorine.With regard t o thefirst, E. Briner,30 reviewing all the work that has been done on theJ. Amer. Chem. SOC., 1927, 49, 1183, 1202; A., 631.28 E. J. Bowen, J., 1924, 125, 1233; A., 1924, ii, 540; R. G. W. Norrish,Com-Unpublished experiments of R. E. Burk, summarised by C. N. Hinshel-J . Chim. physique, 1926, 23, 848; A, 1927, 214.REP. ---VOL. XXTY. LTram. Farday SOC., 1926, 21, 575; A., 1925, ii, 1080; A,, 1926, 584.pare also 0. M. Reiff, J. Amer. Chern. SOC., 1926, 48, 2893; A,, 1927, 67.wood, “ School Science Review,” 1927, p- 169322 ANNUAL REPORTS ON THE PROQRESS OF CHEMISTRY.reaction, concludes that, although water can catalyse the reaction,it is not essential to it.The second reaction is a photochemicalchain reaction of great complexity, in which it is not certain whetherany of the stages are heterogeneous; nor is it certain whetheradsorbed water on the walk, or water in the gas phase is the activeagent. The results quoted above in connexion with nitrogen pent-oxide seem to show that water can play no part in its decomposition.The pentoxide is an " auto-drying " substance, probably moremarkedly so than phosphorus pentoxide, and any trace of waterwould probably form nitric acid. If a trace of nitric acid and thestill smaller trace of water in equilibrium with it were necessaryfor reaction, the rate would be proportional to the nitric acid con-tent.Rice and Getz, however, find that nitric acid is not a catalystfor the decomposition. Moreover, the rate of reaction approachesthe maximum that can be accounted for on any molecular hypo-thesis (see next section), so that if the calculated rate had to be cutdown some thousands of times to allow for the chance of collisionbetween molecules of pentoxide and molecules of water present inexcessively minute concentration, it looks at present as if any ideaof interpreting the facts would have t o be abandoned.With regard t o gaseous explosions, water vapour has long beenknown to catalyse the reaction between carbon monoxide andoxygen in the! flame or in the explosion wave. Dixon showed thatthis was due t o indirect oxidation by way of the water-gas reaction.F.R. Weston31 has recently investigated the conditions both ofthe direct and of the indirect oxidation. He finds from spectro-scopic examination of the flames that both reactions are possible,as Dixon supposed. Water, although providing an easier reactionpath in this instance, is by no means essential; indeed at higherpressures the direct oxidation tends t o predominate.*W. E. Garner and C. H. Johnson 32 have examined the infra-redspectra of wet and dry carbon monoxide burning in oxygen. Theyfind that small amounts of water vapour, which increase the rateof reaction, depress the infra-red emission, and suggest that thewater increases the rate of reaction by causing more energy to beretained in the system.Unimolecular Reactions.There are only three possible reasons why a unimolecular chemicalEither the molecules must be* Compare also C.F. R. Harrison and J. P. Baxter, PhiE. Mag., 1927, [vii],81 Proc. Roy. SOC., 1926, [A], 109, 176, 623.8s Phil. Mag., 1927, [vii], 8, 97; A., 184.reaction should take place slowly.3, 31 ; A., 211UHEMICAL KINETICS. 323in a suitable internal phase before they can react, or they mustwait their turn to come into contact with a catalyst present insmall concentration, or they must be “ activated ” by the acquisitionof energy. Since Arrhenius explained the law of variation ofreaction velocity with temperature in terms of “ active molecules ”it has been recognised that the third condition is the essential one,whether or not the other two come into play as well.The law inquestion is log k = C - E/RT, where C is a constant, and E isthe “ energy of activation,” the form of the equation being explainedby the fact that, according to the kinetic theory, the fractionalnumber of molecules which possess energy, of any kind, exceedingQ is e-Q‘RT multiplied by a factor which does not vary very muchwith temperature. Q is thus nearly the E of the Arrhenius equation,there being a correction which is usually not very large. Thenature of the energy of activation,” and the method by which itis communicated to molecules is now the important question.With bimolecular gas reactions it is plausible t o assume that thekinetic energy of the impact between the two molecules providesthe energy of activation, and on this assumption we find for thenumber of molecules reacting : (number of collisions) x e-E’ap.This equation, in five out of the six known examples, is as nearlytrue as experiment can decide-within a factor of three or fourtimes.= Thus there is no absolute necessity to look any furtherfor the interpretation of bimolecular reactions.As is well known, unimolecular reactions presented a moredifficult problem.J. Perrin’s argument 34 that collisions couldplay no part, and that therefore absorption of radiation must bethe cause of reaction, provoked two important suggestions formechanisms whereby molecules might be activated by collisionand yet react according to a unimolecular law.F. A. Lindemann 35showed that if a molecule received energy by collision but couldnot decompose until it passed through some suitable internalphase, before which it would most frequently lose its excess energy* In view of several statements in the literature of the last year, it is notirrelevant to point out that the energy of activation, or critical energy, is acharacteristic of a reaction, not of a substance. There is an energy of activ-ation for the bimolecular homogeneous decomposition of hydrogen iodide,another for its catalytic decomposition in contact with gold, and yet anotherfor the catalytic decomposition by platinum; but to speak of the energy ofactivation of hydrogen iodide is meaningless.3* W. C. McC. Lewis, J., 1918, 113, 471; A., 1918, ii, 263; C.N. I-finshel-wood, “ Kinetics of Chemical Change in Gaseous Systems,” 1926; R. C.Tolman, J. Amer. Chern. Soc., 1925, 47, 1524; A., 1926, ii, 799; J. A.Christiamen, Proc. Cumb. PhiE. SOC., 1926, 23, 438.84 Ann. Physique, 1919, [ix], 11, 5; A., 1919, ii, 177.ab Trans. Paradag Sm., 1922,17, 698324 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.again in a second collision, then the reaction would appear uninaole-cular over a large range of pressure. At low pressures, however,where the time lag between activation and reaction became com-mensurate with the average time between collisions, the velocitycoefficient would begin to decrease. J. A. Christiansen and H. A.Kramers 36 showed that if “ activated ” molecules of the products ofa reaction could pass on their energy and immediately activate freshmolecules of the reacting substance, thus giving rise to a “ reactionchain,” then also the reaction will follow the unimolecular law.The radiation theory will not be discussed here in detail : it failsin two ways-first, because of the inadequacy of the amount ofradiation in an isothermal system to provide the energy of activ-ation at the required rate, and secondly, because experiments onthe acceleration of reactions by irradiation with the appropriateinfra-red radiation lead t o negative results.The latest investig-ation of this kind is that of G. N. Lewis and J. E. MayerF7 thereaction studied being the racemisation of pinene in the gaseousstate. The pinene was passed a t low pressure through a vesselintensely irradiated with infra-red radiation. The result was thatnone of the racemisation which would have been expected fromthe theory took place.Lindemann’s mechanism demands that the velocity coefficientshall fall at low pressures, but does not predict at what pressurethe effect should begin to be noticeable, since this depends upona specific factor, namely, the average life of an activated molecule.Two years ago the only unimolecular reaction known was thedecomposition of nitrogen pentoxide. H.S. Hirst and E. K.Rideal38 found that at low pressures the velocity coefficient did notdiminish but actually increased. J. H. Hibben,39 however, nowfinds that there is no such increase, but that at pressures between0.2 and 0.002 mm.the velocity coefficient is the same as that foundby Daniels and Johnston for normal pressures. The questionappears to be open : it must be remarked that the difficulties ofavoiding interference by surface reactions at such low pressuresmust be very great indeed. The discrepancy between the resultsof Hirst and Rideal and those of Hibben may be due to some suchcause.Several new examples of unimolecular reactions have, however,now been discovered : the decomposition of gaseous acetone 4036 2. physikal. Chem., 1923, 104, 451; A., 1924, ii, 28.57 Proc. Nat. Acad. Sci., 1927, 13, 623; A., 948.38 Proc. Roy. SOC., 1925, [A], 109, 626; A., 1926, 32.39 Proc. Nat. Acad. Sci., 1927, 13, 626; A,, 948.40 C.N. Hinshelwood and W. K. Hutchison, Proc. Roy. SOC., 1926, [ A ] ,111, 245; A,, 1926, 691CHEMICYAL KINETIOS. 325and the racemisation of pinene41 were the first, and neither ofthem was investigated with respect to the decrease in the velocitycoefficient a t low pressures. The decomposition of gaseouspropaldehyde 42 then proved to be a homogeneous reaction,following the unimolecular law at higher pressures, but falling offin rate at pressures below about 80 mm. The decompositions ofdiethyl ether& and of dimethyl ether44 are similar, the rate ofreaction being independent of the initial pressure above about150 mm. for the first, and above about 300 mm. for the second.These reactions thus appear to behave in the manner predictedby Lindemann’s theory.A remarkable fact about all three is thatin presence of a sufficient concentration of hydrogen the velocitycoefficient does not diminish but retains its normal value exactly.This can hardly be attributed to a direct chemical effect of thehydrogen, since it can only keep the coefficient a t the normal valueand cannot increase it beyond that. In keeping with this, W. F.Busse and F. Daniels 45 find that the nitrogen pentoxide reaction,where the coefficient does not show the diminution, is totallyuninfluenced by hydrogen. The hydrogen thus appears to actmerely by keeping up the Maxwell distribution of energy amongthe molecules of the reacting gas, when the supply of active mole-cules would otherwise begin to fall short of that required to keepthe coefficient constant.All this is in complete accordance withthe theory; but it is remarkable that the action of hydrogen is sospecific, and that helium, nitrogen, and other gases do not havea similar effect. There is, however, great specificity in energytransfers between gas molecules. To quote an example of quitea different kind, the fluorescence of mercury vapour under certainconditions can be reduced to one-half by 0.2 mm. of hydrogen,but only by 30 mm. of nitrogen.46 Again argon and nitrogen havelittle effect on the decomposition of ammonia sensitised to the2537 line by mercury vapour, but small amounts of hydrogen havea large retarding effect.47 The de-activating action of oxygen inthe chlorine-hydrogen combination is another example, since i t4 1 D.F. Smith, J. Amer. Chem. Soc., 1927, 49, 43; A., 212.42 C. N. Hinshelwood and H. W. Thompson, Proc. Roy. Xoc., 1926, [ A ] ,113, 221 ; A., 1927, 26 ; C. N. HinsheIwood and P. J. Askey, ibid., 1927, [ A 1,116, 163; A., 1036.P3 C. N. Hinshelwood, ibid., 1927, [A], 114, 84; A., 212.44 C. N. Hinshelwood and P. J. Askey, ibid., 1927, [A], 115, 216; A., 630.4 = J . Arner. Chem. SOC., 1927, 49, 1257; A., 635.46 H. A. Stuart, 2. Physik, 1926,32, 262; A., 1925, ii, 629; R. Mannkopff,4 7 A. C. G. Mitchell and R. G. Dickinson, J . Amer. Chew&. SOC., 1927, 49,ibid., 1926, 36, 316; A., 1926, 667.1478; A., 739326 ANNUAL REPORTS ON THE PROURESS OF CHEMISTRY.is not at all certain that the inhibiting effect is due to removal ofatomic hydrogen as Nernst suggested.Another unimolecular reaction which behaves in accordancewith the theory has been discovered by H.C. Ramsperger,48 inthe decomposition of azomethane. The constant does not diminishas soon as in the other examples: at 290" k: a t 0-259 mm. hasfallen to one-fourth of its value a t 707.9 mm., and a t 330" over thesame pressure range it falls to one-tenth.There appears thus to be a definite class of reactions to whichLindernann's theory applies; it is significant that all involvemolecules of fairly complex structure, for which a time lag betweenactivation and reaction is not improbabIe a priori. Whether thenitrogen pentoxide decomposition belongs to this class is a t presentan open question, at least as far as the experimental evidence goes.Nature of the Energy of Activation.We have already seen that there is general agreement that therate of nearly all bimolecular gas reactions could be accowted forby assuming that the energy of activation is the translationalkinetic energy of a '' head-on " collision-whether or not this isthe only possible hypothesis. This means, in the language of thekinetic theory, that the total energy of activation is in two degreesof freedom, being made up of the sum of the components of thekinetic energy of each molecule along the line of approach.* Fortwo degrees of freedom of translational energy, the fractionalnumber of molecules-or pairs of molecules in collision, regardedas one system-which have a total energy greater than E is exactlygiven by the factor e--E'RT, and the maximum possible rate ofreaction is 2 .e-E'Rf, where 2 is the collision number.Unimolecular reactions in general proceed a t a rate many timesgreater than this expression requires, e.g., lo5 for the decompositionof acetone,36v40 a fact which a t first sight seemed very difficultto explain. The difEculty can be surmounted by taking intoaccount all the internal degrees of freedom of the molecule. Whenthis is done, a very much greater possible rate of activation isfound.49 The way this comes about is as follows. When energy* The older idea of separate values E, and E, for each molecule disappears48 J . Amer. Chem SOL, 1927, 49, 912, 1496; A., 426, 737.49 G. N. Lewis and D. F.Smith, ibid., 1926, 47, 1608; A., 1926, ii, 799;C. N. Hinshelwood, Proc. Roy. SOC., 1926, [A], 113, 230; A,, 1927, 26; R. H.Fowler and E. K. Rideal, ibid., 1927, [A], 113, 670; A,, 114; J. A. Christian-sen, see Ref. 33.in this way of regarding the matterCHEMICAL KINETICS. 327in a, large number of internal degrees of freedom can count asactivation energy, a total E can be made up in a great many waysowing to the enormous number of possible permutations. Thusthe number of molecules with energy greater than E comes out t oe-E\RT . (E/BT)f”l/l$n - 1, which, for large values of n, is muchgreater than the fraction e-E/RT for two degrees of freedom only;n is the total number of energy terms. (There are two energyterms for each vibrational degree of freedom, since, as Fowler pointsout, there is no reason why potential energy should not count.)The important thing about this expression is that although it maybe much greater than the simple exponential factor, the temperaturecoefficient is about the same.Thus the calculation of E from theArrhenius equation is not much altered, there being a correctionof (4% - 1)RT only. When, therefore, many degrees of freedomparticipate in the activation process, we can have a much greatermaximum rate of reaction for the same experimental value of E .For those unimolecular reactions of which k decreases below acertain pressure, an idea can be obtained of the number of energyterms involved. It may be assumed that, a t the point where thediminution starts, the rate of activation is just great enough tokeep up the normal rate of reaction. (This is merely an approxim-ation, of course.) In this way it can be found that about 12 energyterms* are needed to account for the behaviour of propalde-hyde, 8 for that of diethyl ether, and 11 for that of dimethyl ether.That is to say, 4 to 6 internal vibrations might be involved, whichis a plausible enough result.Fowler and Rideal calculate that even at the lowest pressuresthere are enough collisions to account for the rate of reaction, butonly if the assumption is made that all the energy of two collidingmolecules can flow into one of them.They consider this assump-tion, though not proven, as not impossible. It mould be valid ifthe effective radius of a molecule for de-activation were very manytimes greater than for activation, as is easily shown.On the faceof it, this condition seems an unlikely one, although to explain thevariation with pressure of the polarisation of the resonance radiationof mercury vapour, the effective radius of the mercury atom hasto be assumed many times greater than that indicated by thekinetic theory.50The following table shows how the unimolecular reaction mechan-ism tends to be characteristic of molecules with a more complexstructure.* In some of the original papers theae are inaccurately referred to as degrees6o V. von Keussler, Ann. Physik, 1927, [iv], 82, 793; A., 491.of freedom328 ANNUAL REPORTS ON THE PROURESS OF CHEMISTRY.Unimolecular : Decomposition of N20s, CH,*CO*CH3, C,H,-CHO,C2Hs*O*C2H5, CH,-O*CH,, CH3*N=N*CH3 ; racemisation of C,,H,,.Bimolecular : Decomposition of ZHI, Cl,O, N20, 0,, CH3*CH0.Finally, it should be mentioned that Sir J.J. Thomson 51 hasput forward a theory of unimolecular reactions based upon theidea that the internal energy of a molecule may fluctuate even inthe absence of collisions or of absorption or emission of radiation.The principle of the conservation of energy is abandoned exceptas a statistical result. Whilst the development of this idea willbe watched with great interest by chemists, they will perhapshardly venture to apply it yet., while there is a chance that theirproblems may be solved without the introduction of new physicalprinciples.Bimolecular Gm Reactions.If the theories outlined in the last two sections about the activ-ation of molecules prove to be generally applicable, the distinctionbetween unimolecular and bimolecular gas reactions will becomeone of degree only.* Molecules of simple structure, with a smallenough time-lag between activation and transformation, will reactat once a t a rate proportional to the collision number and thusgive second-order reactions; more complex ones suffer many de-activations and thus give first-order reactions.It has been pointedout42 that two independent facts indicate the soundness of thisway of regarding the matter. First, the approximate correctnessof the calculation of bimolecular reaction rates from the simpleexponential formula for activation in only two energy terms indicatesthat the activation process is one free from complication, andtherefore unlikely apriori to be attended with a time-lag.Secondly,the bimolecular nature of the reaction shows a posteriori that thereis no such time-lag.The decomposition of ozone appears to be a bimolecular processin which rather more energy terms are involved than two of trans-lational energy.52 The heat of activation is, according to recentdkterminations, rather greater than could be supplied by simpleimpact. This reaction would appear therefore to be of a transitionalcharacter, and it is perhaps not without significance that it showsretardation by oxygen, and acceleration by hydrogen, and to asmaller extent by helium and argon.52 It is also stated that chlorine* This does not apply of course to bimolecular reactions where two moleculesare necessary for the reaction to be chemically possible.5 1 Phii!.Mag., 1927, [vii], 3, 241; A,, 212.53 J. W. Belton, R. 0. Griffith, and A. McKeown, J., 1926, 3153; A,, 1927,114; 0. R. Wulf and R. C. Tolman, J. Amer. Chern. SOC., 1927, 49,1650; A,,834CHEMICAL KINETICS. 329retards the reaction a t lower temperatures and accelerates it athigher temperatures. 53Chain Reactions.In oneform it was introduced to explain the enormous deviation of thehydrogen-chlorine combination from Einstein’s law ; and chainreactions are now generally supposed to occur wherever manymolecules are transformed per quantum absorbed in a photo-chemical reaction.Weigert and Kellermann obtained directevidence of the propagation of these chains, and more recentlyF. Porter, D. C. Bardwell, and S. C. LindS4 have found strikingconfirmatory evidence. Over a wide range of conditions they haveshown that the relative amounts of combination of hydrogen andchlorine, provoked by light and by or-particles, are the same. Thisis strong evidence for the propagation of a definite thermal chain,for, as they say, we have “ two entirely distinct physical agents,light and a-particles, acting through different primary steps, excit-ation and ionisation, producing total reaction greatly in excess ofthe unit quantities involved in the primary steps, and yet the totalquantities of action referred back to the unit in each case are equalt o each other.”In a different connexion the chain mechanism was introducedby Christiansen and Kramers36 to account for a kinetically uni-molecular reaction with activation by collision, and to overcomethe difficulty then felt about accounting for the rate of activation.Although the theory has not on the whole found favour in thisparticular application-it is, however, by no means disproved-Christiansen 55 has applied it further in developing a theory ofnegative catalysis. A reaction chain is set up by the handing onof energy from “ hot ’’ molecules of reaction product to moleculesof the reacting substance which thereby become activated andreact in their turn.According to the theory, if a substance iscapable of breaking such a chain by taking away the energy fromone of the “ hot ” molecules, then it can act as a negative catalyst.Although all examples of negative catalysis are certainly not ofthis kind, H.L. J. Biickstrom 56 has recently found interestingevidence that such processes do occur. In the photochemicaloxidation of benzaldehyde, heptaldehyde, and of solutions of68 A. Pinkus and A. Radbill, Bull. SOC. chim. Belg., 1926,35, 461 ; A., 1927,64 J . Amer. Chem. Soc., 1926, 48, 2603; A., 1926, 1111.66 J . Physical Chem., 1924,28, 146; A., 1924, ii, 242.6u J . Amer. Chem. SOC., 1927, 49, 1460; A,, 737. Also Medd. K . Veten-skapsakad. Nobel-Inst., 1927, 6, Numbers 15 and 16; A., 1151.The idea of chain reactions originated in two ways.320.L 330 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.sodium sulphite, there are very high quantum yields, amountingrespectively to 10,000, 15,000, and 50,000 molecules per quantum.This shows that the light probably sets up chain reactions, andthe question arises whether chains are set up in the dark reactionsalso.The photochemical reactions are markedly subject to theaction of inhibitors, which presumably cut short the chains, andthe important point is that the dark reactions are subject to theinfluence of the same inhibitors in an almost exactly parallel way.It looks, therefore, as though we have here an example of chainmechanisms in ordinary thermal reactions.In connexion with the question as to whether chains occur inthe decomposition of nitrogen pentoxide, it should be mentionedthat no inhibitors are known for its decomposition.Busse andDaniels 45 find that not only hydrogen, but also carbon monoxide,bromine, and chlorine are without influence on the reaction, whilstcertain organic vapours promote rapid decomposition and arethemselves attacked.Reactions in Solution.There are several striking facts of a general character aboutreactions in solution. Erst, as Menschutkin showed long ago, thevelocity of a reaction may vary several hundredfold with changeof solvent. No general explanation of this has been found, andit must be concluded that reaction rates are subject to highlyspecific influences of solvent molecules.*Secondly, if we assume that the frequency of collision betweenmolecules A and B is of the same order of magnitude in solutionas a t corresponding concentrations in the gaseous state, and furtherthat the heat of activation is a simple quantity determinable directlyfrom the temperature coefficient, then, as Christiansen has pointedthe effectiveness of collisions in bimolecular reactions isseveral powers of ten smaller in solution than in gases.The assump-tions, especially the second, are, of course, not free from uncertaintyas regards any single example, but from the fact that the result isa general one we must conclude that a large proportion of de-activations occur in solution. I n this connexion it is perhapssignificant that in several unimolecular reactions, where the rateof activation and de-activation does not come into the expressionfor the rate of reaction as long as it is large enough, the velocity* For recent experimental work see W.Blakey, H. McCombie, and H. A.Scarborough (J., 1926,2863 ; A., 1927, 27), H. McCombie, H. A. Scarborough,and F. F. P. Smith (J., 1927, 802; A., 624), B. W. Bhide and H. E. Watson(J., 1927, 2101 ; A., 1036), and G. Muchine, R. Ginsburg, and C. Moissejeva(Ukraine Chem. J., 1926, 2, 136; A,, 1927, 624).67 2. phy&ikal. Chem., 1924, 113, 35; A , , 1925, ii, 47coefficients are the same in solution as in the gas. This was foundby R. H. Lueck 58 for the decomposition of nitrogen pentoxide incarbon tetrachloride solution, and by Smith *l for the racemisationof pinene both in the pure liquid state and in solution.R. G.W. Norrish and F. F. P. Smith au have recently studiedtwo carefully chosen reactions, namely, the interactions of tri-methylamine with m- and with p-nitrobenzyl chloride in non-polarsolvents, with a view to correlating the absolute rates of changewith the values for the energy of activation as calculated from thetemperature coefficients. They find here also that there is amarked de-activating effect of the solvent, which, as they pointout, is not surprising since in solution the mean free path is of thesame order as the molecular diameter, and ‘c nearly every collisionbetween potentially reactant solute molecules must therefore ofnecessity partake of the nature of a ternary collision at least, inwhich the third body is a solvent molecule.”The third important general fact is the marked effect of neutralsalts on the rate of many ionic reactions, which can be accountedfor in terms of the effect of the neutral salt on various activitycoefficients.One of the centres of interest in the past few years has been theproblem of how far, by the introduction of “activities” intoreaction-velocity equations, we can progress towards a satisfactorytheory of ionic reactions and reactions in solution generally. Thefirst to introduce an “activity” theory into considerations ofreaction velocity were van ’t Hoff and Dimroth, who showed that,if concentrations are memured in terms of solubilities, equilibriumconstants become independent of the solvent.Various recenttheories may be briefly discussed.If we consider a reaction A + B A’ + B’, the ordinaryexpression for the equilibrium constant may not hold, in whichcircumstance we shelve the question by writing a,arJa,a,instead of cAcB/cA,cBB,.It is then possible, but by no manner ofmeans necessary, that the rate of the forward reaction should beof the form. . . . . . . . . . h = k,a,a, ’ (1)h = k,c,c, (2)instead of(The fact that the van’t Hoff-Dimroth equation cannot be splitup in this way to give the separate velocities seems to throw somedoubt on this.) The rate of the reaction must be proportional to. . . . . . . . . .s8 J. Amer. C’hern. SOC., 1922, 44, 767; A., 1922, ii, 433.baa J., 1928, 129332 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.the number of encounters between A and B; when the gas lawsare not followed this number is not proportional to cAcB, but thereis no theoretical reason why it should be proportional to a thermo-dynamic function such as aAa,.The question really is, then,whether, when cAcB fails, aAaB gives an empirically better approxim-ation.J. N. Bronsted 59 turns the flank of the difficulty by making therate of reaction proportional to the concentration of a critical com-plex X, formed by the collision of A and B. Thus h = constant . cx.Also ax/aAa, = constant = cxfx/cAfAcBfB : whencewhere fA, fB, and fx are the activity coefficients. Now in generalwe do not know anything whatever about fx, so that we are leftwhere we were, except in so far as equation (3), which is theoreticallyfairly sound, brings out the inadequacy of equation (1) by showingthat the latter assumes an unknown factor fx to be constant.Bronsted has shown, however, that in the special case of reactionsbetween ions the problem becomes soluble in an elegant manner.The activity coefficients of ions in dilute solution are governedmainly by the charges and only to a minor extent by the specificproperties of the ions themselves.Whatever the properties of Xmay be, its charge is simply the sum of the charges of A and B.Thus for fx we use merely the general value for an ion of thatcharge; fA, fB, andf, can now be calculated from the Debye-Huckelequation 6o - logf = A . z21/y where x is the valency of the ion,p the ionic strength 61 of the solution.A is about 0.5. Thush = kCACBf*f,/fX . . . . . . . . . . (3)log (fAf,/f,) = ZAZB2/F . . . . . . . . (4)If A and B have the same sign, X has a greater charge than either,and since the activity coefficient of a highly charged ion diminisheswith the total salt concentration very rapidly compared with thatof an ion of small charge, the factor fAfB/fx increases with the saltconcentration and there is a “ positive salt effect,” and vice wersa.If A or B is a neutral molecule there should be little or no salteffect .Some of the more recent experimental work will now be con-sidered. First, with regard to ionic reactions, the Debye-Hiickellaws only hold a t great dilutions. At moderate dilutions specificeffects come into play which cannot be theoretically predicted.Consequently the only crucial tests of equation (3) are those made69 2.physikal. Chem., 1922, 102, 169; A., 1922, ii, 699; N. Bjerrum,ibid., 1924, 108, 82; A., 1924, ii, 240.60 P. Debye, Physikal. Z., 1924, 25, 97; A., 1924, ii, 386.81 G. N. Lewis and M. Randall, “ Thermodynamics,” New York, 1923CHEMICAL KINETICS. 333in very dilute solution. Two very good examples have beenstudied by J. N. Bronsted and R. Livingston,62 in the reactions[CoBr(NH,),]" + OH' -+ [Co(OH)(NH,),]" + Br' andZ[CoBr(NH,),]" + Hg" + 2H20 -+ ~[CO(NH,)~,H~O].** + HgBr,(undissoc.)Both proceed a t a measurable speed a t the ordinary temperatureand can be followed colorimetrically ; both are bimolecular, therate of the second being determined by the process[CoBr(NH,),]** + Hg" 4.From equations (3) and (4) it can be seen that the logarithm ofthe velocity coefficient plotted against the square root of the ionicstrength should give a straight line of slope xlzz, or - 2 and + 4,respectively, for the two reactions.The experimental results arein excellent agreement with these predictions. Measurements onthe cobaltammines are particularly appropriate, because many ofthem are so sparingly soluble that activity measurements by thesolubility method can be made a t great dilutions, and the applic-ability of the Debye-Hiickel equation can be directly tested by anindependent method.63A. von Kiss and V. B r ~ c k n e r , ~ ~ studying the reaction betweenpersulphates and the iodine ion, find Bronsted's theory confirmedin general outline with specific effects superimposed, and C.V.King 65 finds general agreement with the theory in the oxidationof ammonia by persulphates, catalysed by the silver ion. Numerousspecific effects of various ions on the velocity of decomposition ofpotassium persulphate in aqueous solutions are described by A.Kailan and L. Olbrich.66 H. S. Harned,67 using the data of A. B.Manning68 for the rate of hydrolysis of ethyl formate, assumesthe rate to be given by E[ester]c,. Manning's li: varied with saltconcentration: Harned makes it constant and works back tocalculate yHyB/yBF for formic acid a t different salt concentrations.The results are plausible, more so, Harned thinks, than if a, hadbeen used in the velocity equation.Studying the reaction betweenN-chloroacetanilide and hydrochloric acid, F. G. Soper and D. R.PrydeG9 conclude that the rate is best expressed by kaAaB. Thevalues used for the activity of the chloroanilide were those pre-62 J . Amer. Chem. Soc., 1927, 49, 435; A., 319.63 5. N. Bronsted and V. K. LaMer, ibid., 1924, 46, 655; A., 1924, ii, 306;G2 2. phy/sikal. Chem., 1927, 128, 7 1 ; A., 945.65 J . Amer. Chem. SOC., 1927, 49, 2689.66 Monatsh., 1927, 47, 449; A., 213.G 7 J . Amer. Chem. Soc., 1927, 49, 1 ; A., 206.s8 J., 1921, 119, 2079.V. K. LaMer, C. V. King, and C. F. Mason, ibid., 1927, 49, 363; A., 314.6* J., 1927, 2761334 AHNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.vailing in presence of the hydrochloric acid, determined by anindirect method.These varied by 13% over the hydrochloricacid concentration range (0.1-1*5M), whilst k was constant. Theauthors point out that if Bronsted’s equation were to apply here,the activity coefficient of the intermediate complex would have t,obe assumed constant, which they consider unlikely in view of thevariation in the coefficient of the chloroanilide itself.Dawson and his collaborators 70 have shown in a series of papersthat the classical mass-action equations are capable of giving Rquantitative description of a great number of facts relating t o theaction of iodine on acetone in presence of acetic acid-sodium acetatemixtures (occasionally chloroacetic acid), and to the hydrolysis ofethyl acetate.The dissociation constants used t o calculate pxvalues are those based upon conductivity measurements, and theseare assumed not t o vary with the salt concentration. It is necessaryto assume a specific catalytic action of the hydrogen ion, the acetateion, the hydroxyl ion, and of the undissociated acetic acid. Thevery satisfactory results, however, will not bear very definitely onthe activity problem until the work is extended to the action of“ strong ” acids.The “ dual ” theory of acid catalysis, illustrated by Dawson’swork, has lately been applied again to the hydrolysis of sucrose.71The value of k, the unimolecular velocity coefficient, appears, more-over, to be raised or lowered by glycerol according as the catalystis a strong or a weak acid, but t o be uniformly increased by thepresence of neutral salts.A. Hantzsch and A. Weissberger 7laalso have dealt with the sucrose inversion and put forward a theorythat water forms with strong acida complexes which ionise and arecatalytically active, and with weak acids ester-like complexeswhich are inactive.Soper and Pryde 69 point out that electrolytes may exert aconsiderable influence on the solubility of a non-electrolyte andtherefore, according to the activity theory, should alter its rate ofreaction. In this connexion we may note that J. C. Andrews andF. P. Worley 72 find that sodium chloride has no effect on themutarotation of a-glucose in water : this agrees with Bronsted’stheory.70 H. M. Dawson and J. S. Carter, J., 1926,2282; A., 1926,1108; H.M. D.arld N. C. Dean, J., 1926, 3872; H. M. D. and C. R. Hoskins, J., 1926, 3166;H. M. D., J . , 1927, 213, 455, 756, 1290; H. M. D. and W. Lowson, J . , 1927,2107, 2444; A,, 27, 117, 214, 320, 527, 737, 1150.71 H. Colin and A. Cheudun, J . Chim. physique, 1926, 23, 808; 1927, 24,716 2. physika7. Chem., 1927, 125, 261; A., 525.7s J . Physical Chem., 1927, 31, 882; A., 736.607; A*, 26, 835CHEMICAL KINETIOS . 335Finally, it should be mentioned that the theory attributingcatalytic activity principally to the unhydrated hydrogen ion doesnot seem to be receiving experimental support.73The situation might be summarised as follows. There is notheoretical reason why concentrations should simply be replacedby activities in velocity equations.Empirically, this proceduregives sometimes better and sometimes worse results, as might beexpected when minor complications abound. Bronsted’s equationinvolving the activity coefficient of an intermediate complex is notopen to experimental test except in ionic reactions. Here at lowconcentrations it gives excellent results. (Bronsted’s is essentiallya concentration hypothesis although the equation involves activitycoefficients.) At higher concentrations specific effects are super-imposed. Numerous catalytic reactions proceed a t any rate asthough both the hydrogen ion and the undissociated acid, as wellas the acid anion, had specific catalytic properties. Por weak acids,even in presence of their salts, the classical equations seem to beapplicable over a considerable range.MisceEZaneous Reactions.-Kinetic studies have been made, whichcannot be adequately summarised under one heading, of a numberof various reactions, including the Landolt reaction 74 ; the decom-position and oxidation of dithionic acid 75-the first stage in oxid-ation is hydrolysis ; oxime formation 76 ; the conversion of ammon-ium thiocyanate into thiourea and vice versa 77-both unimolecularreactions ; and many others.Heterogeneous Reactiom.Numerous studies made during the past year continue to showhow equations based upon the adsorption theory can give anadequate description of the kinetics of surface reactions.R. E.Burk 78 finds the decomposition of ammonia on the surface of aheated molybdenum wire to be a reaction of zero order-completecovering of active surface-with a true heat of activation of 53,200cals. G .M. Schwab 79 finds the rate of decomposition of ammoniaat low pressures to be proportional to the presence of ammoniaand inversely to a linear function of the pressures of nitrogen73 M. Bergstein, Physical Chem., 1927, 31, 178; A., 321; G. Schmid and74 A. Skrabal and A. Zohorka, 2. Elektrochem., 1927, 33, 42; A,, 319.7 5 D. M. Yost and R. Pomeroy, J. Amer. Chem. Soc., 1927,49,703; A., 426.7 6 A. Olander, 2. physikal. Chem., 1927, 129,l; A., 1036.77 A. N. Kappanna, J . Indian Chem. SOC., 1927, 4, 217; A., 943.78 Proc. Nat. Acad. Sci., 1927, 13, 67; A., 426.7s 2. physikal. Chem., 1927, 128, 161; A., 946.R.Olsen, 2. physikal. Chem., 1926, 124, 97; A., 1927, 21336 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.and hydrogen. According to A. F. Benton and J. C. Elgin 80 therate of reaction between hydrogen and oxygen in contact withmetallic silver is proportional to the pressure of hydrogen, andindependent of that of the oxygen. It is reduced by the presenceof steam. The decomposition of hydrogen peroxide vapour 81 incontact with quartz is of zero order, and retarded by oxygen, andin contact with platinum, of the first order. The velocity of inter-action of hydrogen sulphide and sulphur dioxide in Pyrex vesselsvaries as the pressure of sulphur dioxide and as the + power of thepressure of hydrogen sulphide.82 A. F. Benton and T. L. Williams 83find a much smaller rate of interaction of carbon monoxide andoxygen in contact with quartz glass than that originally found byBodenstein and Ohlmer, and conclude that pure quartz glassis a relatively inactive catalyst.They find the rate to vary as[O,][CO]l/2. Bodenstein and Ohlmer had found inverse proportion-ality to carbon monoxide pressure. This illustrates the varyingadsorptive properties of different kinds of quartz.Evidence is still accumulating to show that catalytic surfaceshave centres of varying activity. Direct measurements of theadsorption of carbon monoxide and of oxygen by powdered quartzglass indicate that less than 3% of the surface can be involved inthe catalytic oxidation.83 J. A. Almquist 84 estimates that onlyabout one atom in 1000 of pure iron is active in catalysing theammonia synthesis, and (Miss) W.M. Wright 85 concludes that&8y0 of the area of charcoal is effective in catalysing the oxid-ation of various organic acids. F. H. ConstableYs6 from the factthat two simultaneous reactions undergone by ally1 alcohol whenpassed over heated copper are differently influenced by changesin the physical state of the catalyst, concludes that there are twoindependent centres of activity for the two reactions. Similarly,G. I. Hoover and E. K. Rideal 87 find that the two alternative decom-positions of ethyl alcohol by thoria show a specific behaviour withregard to poisons which points to the same conclusion. Burk 78finds that the rate of decomposition of ammonia on molybdenum,although strongly retarded by nitrogen, does not approach zero asthe surface becomes saturated with nitrogen; thus there must be80 J .Amer. Chmn. SOC., 1926, 48, 3027; A,, 1927, 118.81 L. W. Elder, jun., and E. K. Rideal, Trans. Paraday SOC., 1927,23, 545;82 H. A. Taylor and W. A. Wesley, J . Physical Chem., 1927,31, 216; A., 318.83 Ibid., 1926, 30, 1487; A., 1927, 28.84 J. Amer. Chem. SOC., 1926, 48, 2820; A., 1927, 29.8 5 J., 1927, 2323; A,, 1039.8 6 Proc. Roy. SOC., 1926, [A], 113, 254; A., 1927, 27.87 J , Amer. Ciwm. SOC., 1927, 49, 104; A,, 215.A., 1035CHEMICAL KINETICS. 337a reaction on certain parts of the surface which the nitrogen cannotpoison, or else the nitrogen film itself has a certain catalytic property.The possibility that unimolecular gas films on catalysts have, ingeneral, some specific catalytic activity should not be left out ofconsideration ; in many examples it would provide an alternativeto the hypothesis of non-uniformity of the surface--though cumul-ative evidence of a varied kind seems to show that this latterassumption cannot be dispensed with.It is not surprising thatthe study of the more complex phenomena of biochemistry leads tosimilar conclusions. A number of organic substances reducemethylene-blue under the influence of Bacillus coli, which, exposedto adverse conditions of different kinds, loses its activity notsuddenly but step by step towards one after another of thesubstances.8The energy relationships of heterogeneous reactions are rathercomplex : it is necessary to distinguish between the true and theapparent heat of activation, the latter being, in the most generalcase, a function of the heats of adsorption.Since this was clearlyrealised, a good deal of work has been done on the measurement ofheats of adsorption both directly 89 and by indirect methods.90The general results of these show that the differential heat ofadsorption is usually greatest for the first amounts adsorbed, isoften of considerable magnitude, and is changed by various agencieswhich alter the catalytic activity. Quantitative applications tocatalytic reactions are hardly possible yet.A good deal of interesting information has been obtained aboutthe many physical and chemical influences which cause or modifycatalytic activity.A method has been proposed for finding theabsolute surface of a supported metallic catalyst, based uponthe determination of the electrical condu~tivity,~~ and applied tostudy the changes which occur when a copper catalyst is oxidisedand when it is allowed to sinter. Adsorption measurements havebeen applied to obtain an estimate of the area, of the internal surfaceof charcoal.92 According to G. Bredig and R. All0li0,~~ X-rayO 8 J. H. Quasteland W. R. Wooldridge, Biochem. J., 1927, 21, 148, 1224.8D G. B. Kistiakowsky, E. W. Flosdorf, and H. S. Taylor, J. Amer. Chem.SOC., 1927, 49, 2200; A,, 1021 ; W. A. Dew and H. S. Taylor, J. PhysicalChem., 1927, 31, 277; A., 306; S. J. Gregg, J . , 1927, 1494; A., 820; R.A.Beebe, J. Physical Chem., 1926, 30, 1638 ; A., 1987, 23 ; G. B. KistiakowskyProc. Nut. Acad. Sci., 1927, 13, 1; A., 314.*l F. H. Constable, Nature, 1927,119,349; A., 322; J., 1927,1678; A,, 839.O2 W. E. Garner, D. McKie, and B. C. J. G. Knight, J . Phy8ical Chem.,*a 2. physikal. Chem., 1927,120, 41; A,, 602.W. G. Palmer, Proc. Roy. SOC., 1927, [ A ] , 115, 227; A,, 722.1927, 31, 641 ; A,, 617338 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.examination fails to throw any light on structural differencesbetween active and inactive catalysts. An interesting observation,related to promoter action, is that zinc oxide, mixed with copperoxide, is completely reduced by hydrogen at 300°.94It is an important fact that in a heterogeneous catalytic reactionbetween two substances both must usually be adsorbed and broughtunder the direct influence of the catalyst. This appears to beexemplified in an interesting way by some considerations putforward by H.Remyg5 in discussing the catalytic combination ofoxygen and hydrogen. If metals are arranged as far as possiblein the order of their capacity for taking up hydrogen and oxygenrespectively, it appears that those with a large affinity for hydrogenare most active when charged as far as possible with oxygen andvice versa.Comparatively little work has been done on reactions actuallyoccurring in the solid state. W. Jander 96 has worked out a theoryof the interaction of two solids, based upon the laws of diffusion,which he finds to be coniirmed experimentally.J. Hume andB. Topley 97 have studied the dehydration of calcium carbonatehexahydrate. The rate increases to a maximum at about 50%decomposition in accordance with the view that reaction occurs atthe interface between the two solid phases. The presence ofdifferent adsorbed substances has a pronounced effect.Photochemical Reactions.Since the last report on Photochemistry was written (1925),photochemical researches have proceeded principally along estab-lished lines, but with improving technique and an increasinglyclear theoretical background. Measurements of the number ofmolecules transformed for each quantum of light absorbed continueto claim attention. It is now realised that there is no point inregarding individual measurements as a test of Einstein’s law,which is really axiomatic as far as it goes.Such experimentalevidence as it requires is t o be found in the fact that it represents alimiting rule to which a majority of photochemical changes tend toconform. This approximate conformity is due to the accident thatusually the primary photochemical process and the gross result ofthe change are very simply related. The important thing is thatconspicuous deviations allow the detection of more elaboratereaction mechanisms such as chain reactions (see special section).94 W. Rogers, jun., J . Amer. Chem. SOC., 1927, 49, 1432; A,, 737.96 2. anorg. Chem., 1926,157, 329; A., 1927, 28.96 Ibid., 1927, 163, 1; 166, 31; A,, 736, 1037.O 7 Proc. Leeds Phil.Lit. SOC. (Sci. Sec.), 1927, 1, 169; A,, 626CHEMIOAL KINETICS. 339Quantum efficiencies approaching those indicated by the lawof equivalence are found in the decomposition of aqueous formicacid solutions 98 ; they vary somewhat with the wave-length, butit is interesting to note that the two alternative decompositionsof formic acid occur in proportions which do not vary with thewave-length. The photodecomposition of chlorine-water has anefficiency of 1.6 to 2.0, which varies little with wave-length g9 ; theconversion of lactic acid into acetaldehyde and carbon dioxide inpresence of uranyl salts has an efficiency of about unity,l whilstthe decomposition of oxalic acid solutions has a small and variableone, de-activation apparently occurring very easily.2 For thephotolysis of potassium nitrate solutions the quantum efficiencyis very small for wave-lengths greater than 280 pp but increasesrapidly for shorter wave-lengths; at 254 pp it is a function of thehydrogen-ion concentration.Very small efficiencies have beenfound for two examples of the inverse process, chemiluminescence,the oxidation of phosph~rus,~ and of luciferin.Systematic studies of a number of photochemical reactions inrelation to the influence of concentration, addition of foreign sub-stances, temperature, and other factors have been made whichcannot be adequately summarised here.6The influence of intermittent light has been studied by M. Padoaand N. Vita,' who conclude from their results that molecules whichabsorb light in one period of illumination by a given kind of lightmay suffer different fates according to the nature of the light towhich they are exposed in the interval.The oxidation of hydriodic acid in presence of iodine is anotherexample of a reaction involving a halogen where the rate is pro-portional to the square root of the light intensity.Thus theA. J. A h a n d and L. Reeve, J., 1926, 2852; A,, 1927, 29.9D A. J. Allmand, P. W. Cunliffe, and R. E. W. Maddison, J., 1927, 655;A,, 427.R. H. Miiller, Biochem. Z . , 1926, 178, 77; A., 1927, 119.A. J. Allmand and L. Reeve, J., 1926, 2834; A., 1927, 29.D. S. Villara, J . Amer. Chem. Soc., 1927, 49, 326; A., 323.E. J. Bowen and E. G. Pells, J., 1927, 1096; A,, 633.E. N. Harvey, J . Qen.Physiol., 1927,10, 875; A., 901.A. J. A h a n d and collaborators, refs. 98, 99, 2; J. L. R. Morgan andR. H. Crist, J . Amer. Chem. SOC., 1927, 49, 16, 338, 960; A., 216, 323, 428;D. E. Wobbe and W. A. Noyes, jun., J . Amer. Chem. Soc., 1926, 48, 2856;A., 1927, 30; F. Wachholtz, 2. physikal. Chem., 1927,125, 1 ; A,, 323; E. J.Bowen and C. W. Bunn, J., 1927, 2353; A., 1040; A. Berthoud and J.BBraneck, Helv. Chim. Acta, 1927,10, 289; A., 528; J . Chim. physique, 1927,24, 213; A., 528; A. Berthoud a d G. Nicolet, Helv. Chim. Acta, 1927, 10417; A., 739.7 Gazzetta, 1927, 57, 187; A., 528340 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.primary process seems to be the dissociation of the iodine moleculesto give atoms which catalyse the oxidation.8has shown that in illuminatednitrogen peroxide an equilibrium 2N0, s 2N0 + 0, is set up,and suggests that in the photocatalytic decomposition of nitrogenpentoxide the NO, first gives NO which then reacts with N,05 togive 3N0,.Several new investigations on the sensitising actions of mercuryvapour in photochemical changes have been made.Excitedmercury atoms appear to be able to cause the disruption of thelinkings GH, N-H, and 0-H in such compounds as the alcohols,ammonia, and so on.lo A. L. Marshall l1 has studied the synthesisof formaldehyde from carbon monoxide and hydrogen, and con-cludes that atomic hydrogen is first produced, since the rate dependsupon the square root of the hydrogen pressure. R. G. Dickinsonand A. C . G. Mitchell l2 have also studied the decomposition ofammonia under similar conditions.If a quantum hv is given to a diatomic molecule which requiresenergy D to decompose it, the excess, (hv - D ) , should appear astranslational energy.T. R. Hogness and J. Franck have shownthat when sodium iodide vapour a t 650" is decomposed by ultra-violet light of shorter wave-length than the critical value, theDoppler effect of the light emitted by the sodium increases with thefrequency of the activating light in accordance with theoreticalexpectations.The relation between photochemistry and the phenomena offluorescence is a close In this connexion, it is of interest tonote that E. Gaviola has devised a method for measuring theduration of fluorescence,15 and that measurements 16 on varioussubstances give values for the duration of the order 5 x 10-9 second.The combination of hydrogen and chlorine is still, after morethan half a century, a plentiful source of problems.The activefrequencies appear not to be confined to any restricted regions,Recently R. G . W. Norrish8 A. Berthoud and G. Nicolet, Helv. Chim. Acta, 1927, 10, 476; A., 736.9 J., 1927, 761; A., 528.10 H. S. Taylor and J. R. Bates, Proc. Nat. Acad. Sci., 1926, 12, 714; A.,1927, 217. Compare also H. S. Taylor, J . Amer. Chem. SOC., 1926, 48, 2840;A., 1927, 30.11 J . Physical Chem., 1926, 30, 1634; A., 1927, 216.12 Proc. Nat. Acad. Sci., 1926, 12, 692; A., 1927, 217.1s 2. Physik, 1927, 44, 26; A,, 947.14 J. Perrin, Compt. rend., 1927, 184, 1097; A,, 609; F. Perrin, ibid.,1 5 2. Phy&k, 1927, 42, 853; A., 712.16 E. Gaviola, ibid., p. 862; A,, 712; E. Gaviola and P. Pringsheim, ibid.,p. 1121 ; A., 609.1927, 43, 384; A., 510CHEMICAL KINlTICS. 341since, when light is filtered through chlorine, its photochemicalactivity falls rapidly, not towards zero, but towards a definiteresidual value, Thus some of the very feebly absorbed frequenciesmust be active.17 G. B. Kistiakowsky 18 states that intensivedrying of chlorine does not affect the absorption ; nor is any appreci-able part of the absorbed light re-emitted by fluorescence. Thusit seems hard to believe that water can play any part in the dissoci-ation of chlorine molecules. Theref ore in the hydrogen-chlorinereaction water must play a part at some other stage.There has always been some disagreement about the form of theequations for the rate of reaction. N. Thon l9 now questionsChapman's result that excess of hydrogen has a slight retardingeffect ; in a critical survey of the whole problem, he suggests 2o thek[C1212EH21 and shows that, on the general formula - =whole, the apparently divergent results of different investigatorscan be regarded as special cases of this general equation. Withregard to the inhibition by oxygen, he calculates 2 1 that the amountof water formed under ordinary conditions is negligible in comparisonwith the hydrogen chloride produced.E. Cremer 22 suggests the reaction scheme : (1) Cl, + light =C1" + C1; (2) Cl" + C1, = Cl,. ; (3) Cl3= + H, = 2HC1 + Cl" ; (4)Cl" + 0, = 0,. + C1; (5) C l j + 0, = 0,. + C1, + C1; (6) Cl,.=The possible intervention of water vapour is not taken intoaccount. In this mechanism the oxygen no longer acts as a removerof atomic hydrogen-a r6le which the smallness of the water form-ation makes improbable-but degrades the energy of the chlorine asin the original theory of Chapman. Certain discrepancies betweenthe results of various investigators are explained by the suggestionthat reaction (6) may be catalysed by the walls of the reactionvessel. Possibilities of this kind certainly ought to be taken intoaccount.This Mona Lisa of chemical reactions still smiles its bewitchingsmile, leaving us in doubt whether even yet the secret has beencompletely fathomed.dxdt ~"H,l[O,] + k'"C1,Ic1, + c1; (7) C1" = c1.C. N. HINSHELWOOD.17 W. Taylor, Trans. Paraday Soc., 1927, 23, 31 ; A., 216 ; W. Taylor andA. Elliot, ibid., pp. 38, 683; A., 216, 1039.J . Amer. Chem. SOC., 1927, 49, 2194; A,, 1040.lQ 2;. physikal. Chern., 1926, 124, 327; A., 1927, 323.2o " Die Chlorknallgasreaktion," Fortschritte der Chemie, Physik undphysikalische Chemie, Band 18, Heft 11 (Berlin, 1926).21 op. cit., p. 21.4a 2;. ph&kal. Chem., 1927, 128, 285; A,, 947

ISSN:0365-6217    

DOI:10.1039/AR9272400314

出版商:RSC    

年代:1927

数据来源: RSC

摘要:

INDEX OF AUTHORS’ NAMESAAGAARD, C., 81.Abel, 261.Ackermann, C. L., 60.Adam, H. R., 311.Adams, L. H., 307.Adams, R., 87, 182.Adan, R., 216.Adickes, F., 90, 138.Aeschlimann, J. A., 166,183.Al, J., 27.Albrecht, H., 103, 107.Albrecht, O., 100.Alder, K., 179.Allardyce, W. J., 198.Allison, S. K., 304.Allmand, A. J., 339.Allolio, R., 337.Almquist, J. A,, 336.A l s h , N., 277.Alvarado, A. M., 213.Amelung, H., 223, 224.Aminoff, G., 302.Anderegg, F. O., 217.Andersin, M., 104.Anderson, 250.And&, E., 62.And&, G., 238.Andreevski, J., 43.Andrews, J. C., 334.Andrieux, L., 48.Angelescu, B. N., 213.Angeletti, A., 206.Angern, O., 178.Anson, 266, 266.Appleman, C. O., 232, 233.Armstrpng, E. F., 80.Arrhemus, O., 237.Asahera, G., 281.Asahina, Y., 162.Asai, T., 223.Aschan, O., 125.Askenasy, P., 64.Askey, P.J., 325.Aston, F. W., 11, 41.Athanasiu, I., 216.Austin, H. E., 95.Autenrieth, W., 178.Avery, J., 70.Axtmayer, 244, 245.181, 182,Bach, 226.BBckstrom, H. L. J., 329.Baer, E., 64.Baker, H. B., 19, 20, 38, 40.Baker, J. W., 160.Baker, W. E., 220.Balaban, I. E., 182, 188.Balarev, D., 20, 46, 204.Balas, F., 127.Ball, T. R., 216.Balls, A. K., 213.Baly, E. C. C., 14, 40, 225.Balz, G., 49.Bancroft, W. D., 22.Bannister, C. O., 199.Bardwell, D. C., 329.Barger, 264.Barnicoat, C. R., 96.Barrett, A. W., 88.Barriga Villalba, A. M., 195.Barth, T., 286, 298, 306.Barthel, C., 221.Barton-Wright, E. C., 234.Barwind, H., 20.Basche, W., 304.Bassett, H., 66.Bates, J.R., 340.Bauer, R., 209.Baxter, G. P., 42.Baxter, J. P., 30.Bayer, O., 166.Bayliss, L. E., 216.Beck, J. van der, 159.Becker, J. E., 521.Becker, K., 281.Beebe, R. A., 337.Behr, H., 136.Belasio, R., 216.Belche, E., 203, 204..Bell, E. V., 103.Bell, F., 100, 101.Bell, F. K., 261.Bell, R. P., 23.Belton, J. W., 328.Bender, P., 66.Benedetti-Pichler, A., 197.Bengtsson, W., 221.Bennett, G. M., 103.Bennett, J. A. J., 31, 32.Benrath, A,, 60.34344 INDEX OF AUTHORS’ NAMES.Benton, A. F., 336.BBraneck, J., 339.Bercham, R. G., 88.Berg, L., 46.Berg, R., 201, 202, 204, 208.Berger, G., 166, 167, 190.Bergershoff, K., 193.Bergman, A. G., 69.Bergmann, M., 81, 83, 90.Bergstein, M., 36, 336.Berk, L.H. van, 200, 208.Bernardi, A., 187.Berthoud, A,, 339, 340.Bertram, S. H., 86.Bertrand, G., 238.Bezssonoff, 247.Bhagvat, M. B., 122.Bhattacharya, A. K., 229.Bhide, B. W., 330.Biach, O., 96.Bicskei, J., 207.Bilicke, C., 98.Billiet, V., 313.Bilowitzki, G., 83.Biltz, H., 179, 180, 181.Biltz, W., 60.Binz, A., 182.Birch, S. F., 110.Birckenbach, L., 42.Bjerrum, N., 23, 332.Bladergroen, W., 57.Blakey, W., 330.Blanchetidre, A., 214.Block, R., 60.Blunt, D. L., 241.Boas, 246.Bobrownicka-Odrzywolska, A,, 238.Bocchi, C., 187.Bodenstein, M., 320.Bodforss, S., 164.Boedecker, F., 139.Boeseken, J., 84, 87, 104.Bohm, J., 216.Bolli, E., 178.Boelsing, F., 88.Boettcher, E., 192.Bottger, K., 208.Bottger, W., 201, 208.Bogert, M.T., 182.Bohne, A., 128, 141.Bolapv, A. K., 308, 313.Bone, W. A,, 28, 29, 33.Bonhoeffer, K. F., 319.Bonot, A., 213.Boord, C. E., 32.Borsche, W., 97, 134, 136, 138, 139,Bortels, H., 226, 239.Bossuyt, (Mlle.) V., 213.Bourne, C. L. C., 311.Bowen, E. J., 64, 321, 339.Bowen, N. L., 307.Boyd, T. A., 32.140.Boyer, S., 60.Bradley, A. J., 279.Brautigam, M., 60.Bragg, (Sir) W. H., 296.Bragg, W. L., 286,286, 289, 296, 301.Branch, G. E. K., 107.Braun, J. von, 166, 173.Brauns, R., 307.Brazier, S. A., 155.Bredig, G., 337.Bredt-Savelsberg, M., 122.Brenchley, W. E., 239, 240.Brewer, K., 316.Bridel, M., 81.Brindley, W. H., 175.Briner, E., 321.Brinkmann, E., 97.Brintzinger, H., 201, 216.Briscoe, H.V. A., 41.Bristol-Roach, B. M., 226.Britton, H. T. S., 207, 217.Brodkorb, F., 46, 104.Bronsted, J. N., 332, 333.Brotherton, M., 316.Brown, G. B., 289.Browning, C. H., 186.Bruchhausen, F. von, 170, 173.Bruckner, V., 333.Briickner, H., 84.Briill, W., 203.Brukl, A., 206.Brunetti, R., 49.Brunken, J., 148.Brunner, K., 177.Brunotte, H., 126.Buddenberg, O., 169.Buehrer, T. F., 207.Bulow, H., 180.Bunn, C. W., 339.Burger, A., 168.Burgers, W. G., 106.Burgess, W. M., 69.Burk, D., 228.Burk, R. E., 321, 335, 336.Burrell, R. C., 288.Burschtein, R. H., 208.Burton, H., 182, 183, 185, 187.Bmse, W., 316.Bmse, W. F., 64, 326, 330.Butkewitsch, W. S., 222.Butler, F. R., 93.Buttgenbach, H., 312.Buznea, D., 199.Cady, L.C., 198, 204.Caglioti, V., 60, 198.Cahn, R. S., 173.C a b , T., 213.Callendar, H. L., 32.Campbell, 263.Cannegieter, D., 18.Cantelo, R. C., 26INDEX OF AUTHORS’ NAMES. 345Capato, E., 122, 124.Carani, N., 187.Caress, A., 318.Carobbi, G., 312, 313.Carr, F. H., 174.Car&, M. H., 233.Carter, J. S., 334.Casdino, A,, 66.Cassal, A., 57.Cassar, H. A., 212.Cavanagh, B., 216.Cecchetti, B., 187.Cernatesco, R., 199, 205.CesBro, G., 302.Chace, E. M., 233.Chakravarti, S. N., 169, 171.Chalk, L. J., 55.Challenger, F., 223.Chamot, E. M., 200.Chan, S. B., 42.Channon, H. J., 128, 230.Chapman, D. L., 23.Charch, W. H., 32.Charlton, W., 78, 80.Charrier, G., 177.Chaudun, A., 334.Chibnall, A.C., 230.Chick, H., 246, 246.Chikano, M., 225.Christiansen, J. A., 48, 323, 324, 326,329, 330.Christiansen, W. G., 186.Christie, G. H., 101.Chuit, P., 88.Church, C. G., 233.Church, M. B., 223.Ciocalteu, V., 214.Claaasen, A., 20.Claessens, (Mlle.) J., 203.Clarke, S. G., 15, 102, 205.Clawing, P., 45.Clayton, W., 200.Cocconi, G., 188.Coffey, S., 187.Cohen, E., 18, 19, 52.Colani, A., 60.Cole, W. H., 212.Coleman, J. D., 32.Colin, H., 334.Colin, P. G., 28.Collings, G. H., 239.Colman, J., 169.Cone, W. H., 198, 204.Coniglio, L., 312.Conrad, C. M., 233.Constable, F. H., 336, 337.Constantinides, P. A., 53.Cooper, K. E., 114, 150.Copeman, P. R. v. d. R., 242.Corbet, A. S., 59.Corbitt, H.B., 182.Corey, R. B., 199.Cork, J. M., 50, 284.Cornillot, A., 114.Cornog, J., 56.Constable, I?. H., 46.Coupin, 225.Coward, H. F., 318.Coward, K. H., 244.Cowen, L. G., 317.Cowperthwaite, I. A., 22.Cox, C. B., 67.Crapetta, C., 197.Crawford, R. E., 46.Cremer, E., 341.Crist, R. H., 339.Crotogino, H., 59.Crouch, J. F., 193.Cmz, A. O., 88.Cunliffe, P. W., 339.Curtaz, K., 162.Cuy, E. J., 283.Dalmer, O., 132.Damiens, A., 68.Damon, E. B., 236.Danckworth, P. W., 210.Daniels, F., 54, 319, 325, 330.Darapsky, A., 159.Dargan, W., 66.Daubenspeck, G. W., 217.Davidson, F. R., 233.Davidson, J., 235, 237.Davies, C. W., 23.Davies, J. B., 40, 225.Davies, W. L., 232.Davis, B., 14.Dawson, H. M., 33, 36, 334.Deacon, G.E. R., 60.Dean, N. C., 334.De Boer, J. H., 45, 206.De BrouckAre, M. L., 204.Debye, P., 332.De Jong, W. F., 306.Dekker, K. D., 18, 52.Delachaux, L., 65.Delauney, E., 214.De Liefde, W., 20.Demoussey, E., 238.Dennis, L. M., 52, 283.Denny, F. E., 233.Dent, (Miss) B. M., 289.Desev, N., 204.Deshusses, J., 208.Deshuases, L. A., 208.De Smedt, J., 289.Dhar, N. R., 229, 318.Diaz de Plaza, F. M., 181.Di Capua, C., 60.Dick, J., 202, 204.Dickinson, R. G., 283, 325, 340.Diels, O., 146, 159, 179.Dimroth, O., 186.Dokkum, T., 27.Dombacher, P., 131INDEX OF AUTHORS' NAMES.Donath, 246.Donati, A., 216.Dore, W. H., 82.Dode, C., 234.Drain, B. D., 233.Drew, H. D. K., 66, 96.Drossbach, P., 217.Droste-Huelshoff, A.von, 168.Dnunmond, 246.Druschke, K., 201.Dubsky, J. V., 199.Dufraisse, C., 94, 162.Dunning, F., 186.Durrant, R. G., 66.Du Vigneaud, 262.Dwomak, R., 63.Early, R. G., 19.Edwarde, M. J., 60.Eegriwe, E., 197, 199.Egerton, A., 32.Eggleton, G. P., 256, 267Eggleton, P., 266, 267.Eilers, H., 198.Eisenbrand, J., 214.Ekkert, L., 210.Ekwall, P., 201.Elder, L. W., jun., 44,336.Elghozy, F., 90.Elgin, J. C., 336.Elliot, A., 341.Elliott, G. A., 43, 317.Ellis, G. W., 212.Ellis, 0. C. de C., 33.Elod, E., 61, 64.Embden, G., 266, 266, 268.EmelBus, H. J., 66.Emmett, A. M., 233.Emmett, P. H., 304.Emmons, R. C., 306.Emslander, F., 216.Enklaar, C. J., 120.Ephraim, F., 60.Erben, F. X., 182.Euler, H. von, 264, 268.Evans, U.R., 68.Evans, W. L., 63.Ewdd, P. P., 300.Eykman, C., 247.Fairbourne, A., 90.Fairhd, L. T., 204.Fajass, K., 13, 22, 208.Fdciola, I?., 198, 199.FaJtis, F., 93.Farmer, E. H., 84, 93, 117.Farrow, (Miss) M., 60.Farrow, M. D., 110.Fasal, 160.Fauvel, A., 69.Favorski, A,, 66.Favrel, G., 200.Fedorov, E. S., 308.Fellenberg, T. von, 211,294.Fenning, R. W., 27.Ferguson, A., 24.Fernand&, L., 49, 67.Fersman, A. E., 308.Feuerstein, K., 74.Fichter, F., 67.Finch, G. I., 317, 318.Fink, H., 268.Finzi, C., 182.Fischer, E., 80, 90.Fischer, H., 182, 188, 270.Fischer, H. 0. L., 64, 66.Fischer, W., 298.Fiske, C. H., 266.Flaschner, E., 202.Fleury, P., 188.Florence, G., 86.Flosdorf, E. W., 337.Fliirscheim, B., 149.Fogg, H.C., 60.F o b , O., 214.Food Investigation Board, 232.Foote, H. W., 69.Forkel, H., 94.Fosse, R., 213.Foster, G. E., 90.Fourneau, E., 181, 182.Fowler, R. H., 326.Fox, J. J., 14.Friinkel, S., 131.Francis, F., 86.Francis, G. V., 226.Franck, J., 340.Frangoia, (Mlle.) T., 61.Frank, R., 138, 139, 140.Franzen, 223.Frmer, R. P., 33.Fmter, G., 242.F'rebold, G., 306.Freudenberg, K., 76.Freund, M., 173.Friedrich, A., 212.Friedrich, H., 97.Fries, K., 176.Friese, H., 83.Frommer, M., 216.Fry, H. S., 61.Fuchs, O., 212.Fuchs, W., 71, 234.Fukelman, L., 140.Funk, 262.Gabriel, S., 169.Gadamer, J., 173.Giidke, W., 143.Gaffron, H., 228, 229.Gall, H., 68, 69.Gamble, C. J., 212.Gamer, F. B., 16, 17ZNDEX OB AUTHORS' NAMES.347Garner, W. E., 30, 31, 316, 322, 337.Gaspar y Amal, T., 206.Gates, S. F., 32.Gauntlett, H. F., 85.Gaviola, E., 340.Gebauer-Fiilnogg, E., 210.Geijer, P., 302, 312.Geiling, 261.Geilmann, W., 47.Genevois, L., 226.George, W. H., 290.Gerhardt, F., 233.Gericke, W. F., 232.Germann, F. E. E., 56.Germuth, F. G., 206.Getz, D. M., 320.Ghose, T. P., 194.Gibbs, H. D., 210.Gibbs, R. E., 296.Gibson, C. S., 122, 182, 183, 186.Gibson, R. E., 307.Giebe, A., 290.Giemsa, G., 181.Gilbert, B. E., 239.Gilbert, L. F., 80.Gillespie, H. B., 209.Gillet, A., 94.Gillson, J. L., 308.Ginsburg, R., 330.Glaser, E., 76.Gleditsch, (Mlle.) E., 42.Gleditsch, (Mlle.) L., 42.Goebel, 261.Gotzen, A., 120.Goldbach, E., 206.Goldberger, 246.Goldschmidt, V.M., 274, 289, 294,Gollasch, T., 158.Goodson, J. A., 195.Goodyear, E. H., 66, 69.Goralevitch, D. K., 58.Gordon, S. G., 300.GOSS, F. R., 14, 149.Gossner, B., 298, 299.Gottfried, C., 298.Gottfried, G., 287.Goubeau, J., 40.Graham, A. K., 62.Gray, W. H., 186.Gregg, S. J., 337.Griffith, R. O., 328.Grimm, A., 49.Grimm, F. V., 30.G r i m , H. G., 277, 289.Grimmel, H., 142.Grimwood, R. C., 117.Grbh, J., 69.Grosskopf, W., 148.Grosz, P., 23.Grub, G., 68.Griin, A,, 96.Griinberg, A., 104.297, 298.Giinther, P., 216.Guggenheim, (Dr.), 195.Guillemin, V., jun., 290.Gurney, J., 98.Guye, P. A., 42.H w , A. R. C., 235.Haaae, L. W., 206.Habs, 258.Hafstad, M., 206.Hahn, F.L., 47, 201, 204, 205, 207,Hake, A., 54.Halbig, P., 270.Haldane, J. B. S., 260.Hallett, L. T., 211.Hallimond, A. F., 287.Hallwas, F., 134.Hamer, (Miss) F. M., 166.Hammersten, O., 134.Harnmond, F., 187.Hanhart, W., 149.Ham, R. M., 210.Hantzsch, A., 69, 334.Harden, A,, 261.Harden, W. C., 186.Hardin, L. J., 239.Harker, G., 90.Harned, H. S., 333.Harrison, C. F. R., 30.Harrison, (Sir) J. B., 311.Harrison, P. W. B., 15.Hartleb, E., 201.Hartley, H., 318.Hartley, (Sir) H. B., 23.Hartwell, G. A., 260.Hartwig, W., 306.Harvey, E. N., 330.Harvey, J., 127.Harvey, R. B., 333.Haslam, R. T., 20.Hassan, A., 246.Hassel, O., 208, 284, 289.Hauge, T., 285.Hausser, J., 88.Havelock, T. H., 13.Haworth, R.D., 167, 160, 171.Haworth, W. N., 66, 67, 68, 69, 79,75, 77, 78, 80.Healy, A. T., 93.Heczko, T., 200.He& A., 226.Heido, F., 307.Heidelberger, M., 251.Heidrich, (Frl.) D., 181.Heiduschka, A., 210.Heilbron, I. M., 127, 248.Hein, F., 214.Helderman, W. D., 19.Helferich, B., 76, 80, 81.Hellstrom, 268.Henderson, L. M., 47.216348 INDEX OF AUTHORS’ NAMES,HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHnn:endricks, S. B., 98, 283, 290.:engstenberg, J., 82.h k e , T. A,, 59.:enley, F. R., 261.:enry, J. A., 187, 194, 195.:ensinger, W., 212.entschel, H., 216, 282, 283, 304.:ermann, C., 300.lermsen, W., 192.:errmann, A., 202.&rick, H.T., 223.:em, W., 17.:erzfeld, K. F., 14.:ess, A. F., 248, 260.:ess, K., 72, 82.:evesy, G. von, 46, 215.ibben, J. H., 324.:ickinbottom, W. J., 78, 80.:ildebrsnd, O., 178.ilditch, T. P., 86, 89, 127.ill, Robert, 265, 271.:ill, Robin, 288.:inshelwood, C. N., 317, 321, 323,324, 325, 326.:irano, N., 120.h t , E. L., 67, 68, 69, 70.irst, H. S., 319, 324.:odakow, J., 209.bdgson, H. H., 95.Mbling, R., 52.Iolzl, F., 59.:onigschmid, O., 40, 41, 42.bet, 257.:offman, W. S., 213.loffmann, F., 185.[ofmsnn, K. A., 64.[ofmsnn, U., 64.[ogness, T. R., 340.:olden, H. F., 265.lolleman, A. F., 186.lolmes, E., 85.rolmes, E. L., 149.:alter, H., 169.[onold, E., 141.[onsig, E., 234.[ood, N. R., 40, 225.loover, G.I., 336.[ope, E., 167.iopkins, B. S., 49.Lorn, D. W., 46.[orne, A. S., 233.[oskins, C. R., 33, 334.[ouot, 18, 52.[owell, 0. R., 58, 288.[oyles, E., 247.iuckel, W., 94, 97, 99.[iittig, G. F., 45, 59.[uggins, M. L., 277, 283, 290.[ugh, W. E., 111.[ughes, A. L., 318.[urne, J., 308, 338.[ume-Rothery, W., 280.iwnphreys, R. W., 68.Hund, F., 276.Huntenberg, W., 72.Hunter, H., 14.Hurtley, W. R. H., 116.Hutchison, W. K., 317, 324.Huybrechts, If., 201.Inghsm, B. H., 153.Ingleson, H., 27.Ingold, C. K., 14, 108, 109, 113, 114,117, 119, 149, 150, 151, 153, 155.Ingold, E. H., 114.Ionescu-Matiu, A., 213.Ipatiev, V., jun., 43.Ipatiev, V. N., 43, 86.Irvine, (Sir) J.C., 226.Irwin, M., 236.Ishimam, S., 200.Iterson, van, 234.Jacobi, J., 207.Jacobi, R., 128, 129, 130, 139, 143.Jacques, A. G., 236.Jaeger, F. M., 281.Jiinecke, E., 60.Jahn, C., 206.Jakob, J., 295.James, C., 50.James, R. W., 304.Jander, G., 203.Jander, W., 338.Jansen, 246.Jantsch, G., 50.Jaxon-Deelman, J., 107.Jendrassik, 249.Jenke, 263.Job, A., 57.Job, P., 46.Johansson, C. H., 280.Johner, H., 82.Johnson, C. H., 30, 322.Johnson, J. D. A., 110, 185.Johnson, M. R., 40, 225.Johnson, R. C., 53.Johnston, E. H., 320.Jones, D. I., 67, 68.Jones, E. E., 89.Jones, 0. G., 56.Jones, G. H. G., 222.Jones, R. H. B., 306.Jones, T. G. H., 120.Joshi, S. S., 317.Jost, W., 320.Jouot, 203.Jurgens, J., 187.ICahler, 0..76.Ksilan, A., 333.Kalnins, A., 220.Kamenz, E., 97KrauskoDf. F. C., 198. Kameyama, N., 216.Kaminska, H., 200.Kaminsky, G., 319.Kamm, E. D., 127, 248.Kappanna, A. N., 336.Karantaais, T., 62.Kargin, V. A., 216.Kas6, T., 60.Kawakami, 242, 243.Kay, F. W., 97.Keenan, G. L., 210.Keesom, W. H. M., 289.Keilin, 266, 266, 268.Keller, O., 184.Kemenyffi, 249.Kemmerer, G., 211.Kenner, J., 101, 187.Kenyon, J., 15, 102.Kermack, W. O., 161.Kerschbaum, M., 88.Keussler, V. von, 327.Kilpatrick, M., jun., 36.Kilpatrick, M, L., 44, 319.King, C. V., 333.King, H.., 181, 182, 188.Kirchhof, H., 141.Kirchner, E., 133.Kirrmann, A., 64.Kiss, A. von, 333.Kistiakowsky, G. B., 337, 341.Kitaso, T., 226.Kitasato, Z., 172.Kittl, E., 311.Klever, E., 44.Klingstedt, F.W., 210.Knehe, E., 83.Knieke, L., 122.Knight, B. C. J. G., 337.Knoevenagel, E., 66.Knopf, E., 76.Knorr, C. A., 13.KBhler, A., 89.Kanig, J., 66, 221.Konig, W., 165.Koepfli, J. B., 169.Kording, P., 146.Koets, P., 206.Kohler, E. P., 93.Kolbe. A., 173.Kol10,- (Mrs.) C., 213.Kolthoff, I. M., 198, 200, 204, 208,Kon, G. A. R., 109, 110, 111, 112.Kon, S. K., 246.Kondo, H., 173.Kondo, T., 173.Konen, H., 216.Kooy, J., 19.Kracek, F. C., 47.Kracovski, J., 84.Kramers, H. A., 324, 329.KranjEevib, M., 203.Kraus, C. A., 23, 69.209, 216.ttIIttII11111I(rams, %’.; 47, 104.Crams, J., 202.(resel, A., 213.Crestinski, W. N., 61.(rings, W., 60.(rohnke, F., 198.Iruglov, A., 62.Crzikalla, H., 160.hbina, H., 197.Kuhn, P., 186.ECuhn, R., 100, 103, 107.Kulenkampff, A., 136.Kunze, W., 60.Kurtenacker, A., 206.Lambie, 263.LaMer, V. K., 333.Landsteiner, 262.Lang, R., 204.Lange, E., 97.Langedijk, S.L., 104.Latimer, W. M., 149.Lattey, R. T., 24.Lawson, 247.Learner, A., 69, 70.Leavenworth, C. S., 213.Lebeau, P., 68.Le Bel, J. A., 94.Lecher, H., 209.Lees, N. D., 182.Le Fbvre, R. J. W., 210.Le Guyon, R. F., 204.Lehmann, G., 69.Lehmstedt, K., 212.Leibowitz, J., 263, 264.bitch, (Miss) G. C., 81.Leithe, W., 174.Lemanczyk, K., 236.Lennard-Jones, J. E., 289.Lesslig, R., 206.Levene, P. A., 76, 264.Levi, G. R., 281.Levi, M., 60.Levine, 262.Levy, (Mlle.) J., 66.Levy, P., 125.Lewis, B., 320.Lewis, G.N., 25, 27, 324, 326, 332.Lewis, J. S., 32.Lewis, W. C. McC., 323.Lewis, W. L., 182, 185.Liebe, F., 121.Lieder, H., 58.Lifschutz, I., 129.Lillie, 246.Limpiicher, R., 96.Lind, S. C., 32, 329.Linde, J. O., 280.Lindeman, T., 206.Lindemann, F. A., 323.Lindemann, H., 214350 INDEX OR’ A”IIOR8’ NAME%Lindner, F., 270.Lindner, J., 2 11.Ling, A. R., 83.Linstead, R. P., 108, 110, 111, 112.Lipman, C. B., 239.Lipp, P., 120.Little, E., 216.Littman, Z., 207.Livingston, R., 333.Loach, J. V., 68, 78, 80.Locquin, R., 90.Loew, O., 226.Lohmann, K., 260.Long, C. W., 68, 77, 78, 80.Loon, J. van, 89.Lorentz, R., 17.Lovell, W. G., 32.Lowndes, J., 213.Lowry, T.M., 16, 19, 36, 66, 74.Lowson, W., 33, 334.Lublin, A., 264.Lueck, R. H., 331.Lukens, H. S., 216.Lunde, G., 284, 286,294.Lunt, R. W., 61, 317.Lustig, B., 211.Lyons, E., 197.Macchia, O., 197.McCleland, N. P., 105, 182.McCollum, 261.McCombie, H., 166, 330.McCutcheon, T. P., 282, 283.MacGillivray, J. H., 237.McHargue, J. S., 239.McHatton, L. P., 66.MacInnes, D. A,, 22.Mack, E., 32.McKeown, A., 328.McKie, D., 337.McLean, F. T., 239.McLennan, J. C., 66, 289.McNabb, W. M., 207, 208.Maddison, R. E. W., 339.Madelung, W., 116, 116.Main Smith, J. D., 48.Maiwald, K., 237.Majima, R., 189.Malet, G., 88.Mali, S. B., 19.Malkin, T., 96.Malquori, G., 60.Mameli, E., 187, 188.Manchot, W., 66, 68.Mann, F.G., 104.Mannich, C., 168, 162, 168.Manning, A. B., 333.Mannkopff, R., 326.Manske, R. H. F., 160, 162.Marckwald, W., 168.Mardles, E. W. J., 32.Mmhenkel, E., 91.Marjanovib, V., 206.Mark, H., 289, 290, 304.Markowicz, E., 66.Markowitz, J., 263.Marks, 267.Marrian, G. F., 128.Marshall, A. L., 340.Martens, R., 213.Martin, J., 207.Martini, A., 197.Marvel, C. S., 209.Maschmann, E., 188.Maskell, E. J., 229, 240.Mason, C. F., 333.Mason, C. W., 200.Matthes, H., 209.Maxymowicz, W., 201.May, C. J., 110, 112.May, 0. E., 223.Mayer, J. E., 324.Meckwitz, J., 49.Medweth, J., 177.Meier, W., 166.Meinl, K., 234.Meisel, H., 282.Meisenheimer, J., 100.Meisner, N. I., 210.Meiter, E. G., 318.Mellana, E., 216.Melle, F.A. van, 290.Menke, J. B., 84.Mentml, R., 97.M e n d , H., 49.Menzer, G., 303.Merwin, 31. E., 300, 302, 304, 307.Meyer, A., 214.Meyer, H., 206, 207.Meyer, J., 66, 126.Meyer, K., 260.Meyer, R., 226.Meyer, W., 178.Meyerhof, 269, 260.Meyersohn, P., 83,Micheel, F., 72, 83.Michetti, A,, 187.Mie, G., 82.Migliacci, D., 197.Mik6, J. VOD, 199.Miller, E. J., 67, 69.Miller, E. V., 232.Milobedaki, T., 200.Mills, W. H., 99, 100, 102, 164, 165,Mirchandani, T. J., 87.Mirsky, 266, 266.Mitchell, A. C. G., 326, 340.Mitra, A. K., 49.Moesveld, A. L. T., 19.Moissejeva, C., 330.Moles, E., 40, 42.Montequi, R., 197.Moore, 243.Moore, T. S., 149.181INDEX OB AUTHORS’ N-. 351Morey, G. W., 287.Morgan, G. T., 86, 96.Morgan, J.L. R., 339.Morgan, W. T. J., 262.Morton, R. A,, 14, 248.Moser, L., 200, 201, 206.Mosettig, E., 170.Moureu, H., 162.Mouromtsev, B., 43.Mozolowski, W., 267.Muchine, G., 330.Muller, Adolf, 168.Muller, Alex., 291.Muller, E., 48, 69, 216.Miiller, H., 264.Muller, J., 69.Miiller, J. H., 52, 283.Muller, K., 188.Muller, R., 182, 188.Muller, R. H., 339.Murakami, T., 60.Muravlev, L. N., 205.Mussgnug, F., 298, 299.Myddleton, W. W., 88.MyrbEck, K., 264.Nachmann, M., 203.Nachtwey, P., 179.Nagel, W., 85.Nakamiya, 242, 243.Narayanan, B. T., 1 10.Necritche, M., 206.Nedelmann, H., 51.Nekrassov, R., 96.Nelson, E. K., 233.Neogi, P., 49.Nernst, W., 23.Nestle, K. T., 104.Neuborg, 253, 254.Newitt, D. M., 29.Newman, R.K., 90.Nicholson, V. S., 70.Nicklin, G. N., 182.Nicloux, M., 211.Nicolet, B. H., 154.Nicolet, G., 339, 340.Nicoll, W. D., 63.Niel, C. B. van, 212.Niesse, M., 206.Nightingale, G. T., 242.Niklaev, V., 43.Nikolaiev, V. T., 69.Nishikawa, H., 161.Nitta, I., 290.Noack, K., 229.No6, A., 75.Noethling, W., 290.Nonhebel, G., 23.Norrisli, R. G. W., 64, 321, 331, 340.Nothnagel, M., 168.Noyes, W. A., 49, 106.Noyes, W. A., jun., 339.Nutland, J. H., 110.Oberhauser, F., 200, 212.Oberlin, M., 167, 170.Oddo, G., 66.O’Dwyer, M. H., 234.Olander, A., 336.Ohle, H., 78.Ok&E, A., 199.Olbrich, L., 333.Olivier, S. C. J., 166. 157.Olsacher, J., 306.Olsen, R., 336.Onsager, L., 22, 24.Oppenheimer, 269.Orcel, J., 299, 306.Ormont, B., 61, 197.Orthmann, W., 23.Oschatz, F., 216.Osterhout, W.J. V., 236.Ostmann, W., 60.Owen, E. A., 280.Owens, W. M., 127.Paal, C., 87.Packer, J., 60.Padoa, M., 339.Paetzold, H., 179.Palkin, A. P., 60.Palmer, W. G., 337.Paneth, F., 44.Parkin, J. D., 102.Parnas, J. K., 257.Parsons, A. L., 308.Partington, J. R., 25, 65.Pascual Vila, J., 141.Pauling, L., 273, 304.Pauly, H., 74.Pawletta, A., 55.Payman, W., 32.Pearson, L. K., 224.Peat, S., 76.Peel, J. B., 20, 38.Pells, E. G., 54.Perietzeanu, D. J., 205, 238.Perkin, W. H., jun., 98, 99, 117,160, 161, 167, 169, 171.Perkins, G. A., 88.Perrin, F., 340.Perrin, J., 323, 340.Peters, K., 44.Peterson, V. L., 212.Petrova, M.A., 86.Pfau, E., 210.Pfeiffer, M., 124, 126.Pfeiffer, P., 178.Pfifferling, P., 63.Pfundt, O., 215.Philipp, E., 169.Phillips, H., 16, 102.Phragmh, G., 278352 INDEX OB AUTHORS’ NAMES.Pickett, C. F., 45.Pictet, A., 75, 83.Piggott, H. A., 109.Pigulevski, G. W., 86.Pike, E. F., 62.Pinkus, A,, 203, 207, 329.Piper, S. H., 95.Pirsch, J., 93.Pittarelli, E., 210.Plancher, G., 188.Plant, J. H. G., 77.Plant, S. G. P., 98.Plichta, J., 197.Plimmer, R. H. A., 213, 246.Poggi, R., 211.Pohland, E., 289.Pollard, A., 149.Polverini, A., 21 1.Popov, P. P., 159.Porlezza, C., 215.Porter, C. W., 225.Porter, F., 329.Prahl, W., 66.Prandtl, W., 49.Pregl, F., 135.Preobraschenski, N., 63.Preston, G. D., 280.PAvost, C., 117.Prideaux, E.B. R., 16, 67.Pringsheim, H., 83.Pringsheim, P., 340.Pryde, D. R., 333, 334.Pryde, J., 68, 255, 256.Pschorr, R., 173.Pumm, W., 203.Pyman, F. L., 174, 175.Quastel, J. H., 337.Rabinowitsch, A. J., 216.Rabinowitsch, E., 318.R&c, F., 210.Radbill, A., 329.RBth, C., 182.RahlBn, E., 148.Rakshit, J. N., 174.Ramart-Lucas, (Mme.), 160.Ramelot, H., 201.Ramsdell, L. S., 306.Ramsey, J. B., 205.Ramsperger, H. C., 226, 326.Randall, M., 25, 27, 332.Raper, H. S., 224.Raper, R., 181.Raschig, F., 66.Raschig, K., 75.Rasuwajew, G., 86.Rau, M. G., 125.Rauch, H., 76, 80.Rauchenberger, 263.Ravitch, M., 203.Ray, J. N., 162.Ray, W. L., 154.Raymond, 246.Reader, 246.Reed, H. S., 235.Reed, J. B., 15.Reed, J.H., 164.Reeve, L., 339.Reeves, H. G., 64.Refsum, A., 288.Rege, R. D., 220.Regeimbal, L. O., 233.Reid, E. E., 211.Reiff, 0. M., 44.Reihlen, H., 54, 104.Reimlinger, S., 56.Reinartz, F., 120.Reinwein, 264.Reis, A., 215.Reissaus, G. G., 217.Remy, H., 338.Restaino, S., 60.Reverey, G., 128.Rheinboldt, H., 209.Rheinheimer, W., 184.Rice, F. O., 36, 44, 319, 320.Richardson, 0. W., 316.Rideal, E. K., 44, 63, 318, 320, 324,Riding, R. W., 14.Rjdley, G. N., 294.Riemann, T., 132, 134.Rienacker, G., 216.Riesenfeld, F., 210.Riesenfeldt, H., 168.Riley, H. L., 40.Rinne, F., 282, 283, 304, 306.Rippel, A., 226, 237.Ripperton, J. C., 230.Rivett, A. C. D., 60.Roberts, E., 163, 163, 183.Roberts, R. H., 242.Robertson, A., 74.Robertson, (Miss) M.C., 167.Robertson, P. W., 96.Robertson, (Sir) R., 14.Robinson, G. W., 222.Robinson, P. H., 100, 101.Robinson, P. L., 20, 38, 41, 52.Robinson, R., 149, 160, 161, 162,167, 264.Robinson, W. O., 222.Robison, 262.Rodebush, W. H., 149.Rodis, F., 216.Rogers, 246.Rogers, H. W., 199.Rogers, W., jun., 338.Rojahn, C. A., 176.Roka, K., 212.Rolla, L., 49.Roscoe, 245, 246.Rosedale, 246.326, 336INDEX OF AUTHORS’ NAMES. 353Rosenbach, A., 132.Rosenmund, K. W., 168.Rossi, G., 187, 188.Rossi, L., 199.Roth, H., 207.Rothstein, E., 115.Rouiller, 261.Routala, O., 83.Rubin, B., 62.Ruping, H., 50.Rukoni6, G., 203Rump, W., 317.Rupp, E., 188.Rutherford, (Sir) E., 12.Ruzicka, L., 87, 121, 122, 123, 124,125, 127.Sabalitschka, T., 238.Sagaidatchni, A., 203.Sah, P.P. T., 89.Salkind, J. S., 61, 62.Salmon, 245.Salvesan, J. R., 284.Salzmann, R., 83.Sampey, J. R., 154.Sanchez, J. A., 209.Sander, G., 215.Sandin, R. B., 154.Sandved, K., 217.Sarkar, P. B., 50.Sarver, L. A., 203.Sasahara, T., 281.Sato, K., 31, 316.Sauerwald, A., 158.Saunders, S. W., 25, 31, 316.Scaletti, U., 60.Scanavy-Grigorieva, M., 44.Scarborough, H. A., 330.Scarth, G. W., 236.Schiichterle, P., 58.Schafer, W., 81.Schaller, W. T., 313.Scharrer, K., 222, 240.Scheff, G., 214.Scheffer, F. E. C., 27.Scheffers, H. W., 86.Scheibe, E., 290.Scheibler, H., 91.Schenk, M., 128, 134, 139, 141.Schiebold, E., 304.Schiedewitz, H., 87.Schiele, H., 191.Schindler, H., 99.Schinz, H., 124, 125.Schleede, A., 290.Schleicher, A., 215.Schleusener, W., 237.Schlichting, O., 130, 141.Schlubach, H.H., 72, 253.Schluttig, W., 203.Schmalfuss, H., 213, 214.Schmid, G., 335.REP.-VOL. XXIV.Schmid, R., 59.Schmidt, E., 234.Schmidt, H., 185, 186.Schmidt, J. M., 59.Schmidt, L., 83.Schmitt, K. O., 200, 208, 223.Schnegg, H., 234.Schneider, E., 290.Schniderschitsch, N., 182.Schoeller, W. R., 206.Schoninger, W., 200.Schoep, A., 312.Schopf, C., 192.Schoor, A. van, 139, 143.Schoorl, N., 209.Schoh, S. A., 62.Schtschukina, M., 63.Schuette, K. A., 89.Schulonberg, W., 137.Schulze, E. L., 61.Schulze, H., 190.Schumm, O., 265,268.Schupp, 0. E., jun., 207.Schwab, G.M., 335.Schwaibold, J., 240.Schwartz, W., 240.Schwarzkopf, E., 128.Schweitzer, E., 215.Sconzo, A., 56.Sedgwick, W. G., 99.Seekles, L., 207.Seeley, E. A., 119.Semba, T., 215.Ssmiganovsky, N., 2 14.Sen, J. N., 194.Sen, M., 162.Senior, J. K., 95.Seward, R. P., 23.Shanassy, H., 40, 225.Shannon, E. V., 311.Sharp, T. M., 187, 194.Shaw, E. H., 211.Shaw, F. R., 151.Sheehy, E. J., 241.Sheppard, A. B., 183.Sherman, 244, 245.Shilling, W. G., 25, 27.Shoesmith, J. B., 156.Shoppee, C. W., 108, 113, 115.Shukov, I. I., 216.Sidgwick, N. V., 16, 37, 81, 105.Siefkin, W., 209.Siegfried, 214.Signer, R., 82.Sigova, M. P., 61.Simmonds, 251.Simmonet, 264.Simmons, J. P., 45.Simola, 264.Simon, A., 55.Simon, F., 281.Simonsen, J.L., 87, 122, 125, 194.Sjollema, B., 207.354 INDEX OF AUTHORS' NAMES.Skellett, A. M., 318.Skrabal, A,, 335.Slater, R. H., 156.Slotta, H,, 180.Smiles, S., 116.Smith, D. F., 325.Smith, E. W., 153, 155.Smith, F. B., 120.Smith, F. F. P., 330, 331.Smith, F. L., 211.Smith, G. F., 35, 47, 154, 200.Smith, H. C., 20, 38, 41, 52.Smith, J. L. B., 164.Smith, J. W., 20, 38.Smith, N. H., 41.Smith, S., 195.Smits, A., 19, 20, 21, 38.Smyth, F. H., 307.Sobotke, H., 76.Someya, K., 202,203, 205, 217.Sommer, A. L., 239.Sommerfeld, A., 277, 289.Soper, F. G., 153, 333, 334.Sorge, H., 129.Spacu, G., 202, 204.Spath, E., 168, 169, 170, 173, 174,Spassov, A., 46.Speight, E. A., 113.Spencer, L.J., 292, 300, 303, 309,310, 311, 313.Spengles, O., 230.Spirescu, (Mlle.) E., 200.Sponsler, 0. L., 82.Stackelberg, M. von, 94.Staden, A. von, 132, 142.Stahn, R., 83.Stark, 0. K., 231.Starkweather, H. W., 42.Starr, I., jun., 212.Staudinger, H., 82.Steenbock, 244.Steger, A., 89.Steger, R., 87.Steiger. R., 124.193.SteGanov, A., 63.Stepf, F., 97.Stwhen, W. E.. 40. 225.Stekdemann, W., 69.Stevens, T. S., 167, 172.Stewart, J., 241.Stewart, N., 97.Stiegler, H. W., 185.Stimson, J. C., 318.Stippler, H., 170.Stock, A., 48.Stockwell, C. H., 303.Stockwell, R. C., 306.Stolfi, (Miss) A., 59, 60.Stoll, H., 87.Stoll, M., 124.Strebinger, R., 202.Streoker, W., 202.Stroh, W., 193.Stuart, H. A., 325.Subbarow, 256.Subramanian, V., 221, 223.Sugden, S., 15, 16, 17, 105.Sundstrom, E., 210.Sure, 250.Swarbrick, T., 230.Swart, E., 20.Swarts, F., 61, 90.Swartz, C.E., 198.Szebellddy, L., 205.Szyszkowski, B., 24.Takahashi, T., 223.Talenti, M., 206.Tamiya, H., 225.Tammann, G., 20, 281.Tananaev, N. A., 196.Tenner, 246.Tanret, G., 264.Tartar, H. V., 28.Tasman, A., 157.Taube, C., 64, 65.Taylor, H. A., 336.Taylor, H. S., 337, 340.Taylor, W., 288, 341.Taylor, W. E., 156.Taylor, W. H., 286.Tenney, F. G., 222.Tereschenko, A., 205.Terpstra, P., 281.Thaler, E., 55.Thannhsuser, 262.Thaysen, A. C., 220.Thewlis, J., 279.Thibaud, J., 95.Thilo, P., 41.Thom, C., 223.Thomas, W., 230.Thompson, H. W., 325.Thorns, H., 193.Thomson, (Sir) J.J., 328.Thornson, E., 306.Thomson, W. F., 89.Than, N., 341.Thorpe, J. F., 14, 113, 117, 119.Tiedje, W., 282.Tiffeneau, M., 65.Tizard, H. T., 27.Toivonen, J., 117.Tolman, R. C., 320, 321, 323, 328.Tomecko, C. G., 87.Topley, B., 308, 338.Toussaint, L., 216.Townend, D. T. A., 29.Travers, A., 18, 52, 203.Trader, R. N., 65.Treedwell, W. D., 217.Trbfouel, J., 182.TrBfouel, (Mme.) 5, 182.Trefz, F., 234INDEX OF AUTHORS’ NAMES. 355Treibs, A., 214.T1pessler, (Miss) K. M., 52.Trieloff, H., 176.Trikojus, V. M., 90, 167.Trimble, H. M., 200.Tronov, B. V., 169.Tropp, C., 181.Tschirwinsky, P., 310.Tsiyimoto, M., 127.Turner, E. E., 153, 163, 183, 210.Tutton, A. E. H., 304.Uhlenhuth, P., 186.Ulmann, M., 48.Urbain, G., 60.Vaoha, G. A., 233.Vbeautan, (Mlle.) E., 205.Vaas, C.C. N., 153, 165.Vecchiotti, L., 187.Vedder, 247.Vegard, L., 285, 288.Venkateswaran, R., 61.Verley, A., 92.Vickery, H. B., 213.Vieweg, K., 204.Villars, D. S., 339.Vinson, C. G., 232.Virtanen, A. I., 126.Vita, N., 339.Vleeschhouwer, J. J., 216.Volker, F., 116.Voellmy, H., 14.Vogel, H., 75.Vogel, I., 24, 114.Vohsen, E., 281.Volk, H., 139.Vongerichten, E., 89.Voorhies, A., 213.Vosnessenski, S. A., 64.Votodek, E., 210.Wachholtz, F., 339.Wagenaar, M., 209, 210.Wahl, W., 104, 294, 296.Waksman, S. A., 222.Walker, T. K., 223.Walker, T. L., 308.Walther, O., 168.Wang, L., 178.Wang, S., 169.Warburg, E., 317.Warburg, O., 269.Ward, W.J. V., 102.Wardlaw, W., 67.Ware, A. H., 199.Warington, K., 239, 240.Wasastjerna, J. A,, 274.Washington, H. S., 300, 302.Waters, 256, 256.flatson, E. R., 162Watson, H. E., 330.Webster, T. A., 243,248, 249.Weil, F. J., 129.Weiler, G., 206, 216.Weise, A., 238.Weissberger, A., 334.Weissenberg, K., 93, 290.Welsbach, A. von, 41.Wendt, G. L., 30.Wesley, W. A., 336.West, A. P., 211.West, E. S., 212.West, J., 285, 286, 301.Westenbrink, H. G. K., 69, 281, 284,Westgren, A., 278.Weston, F. R., 29, 322.Weygand, C., 94.Weyland, P., 128, 129, 133.Wheeler, 246.Wheeler, R. V., 32, 33.White, E. C., 320.White, F. D., 264.Whitenack, T. A., 216.Whittaker, H., 16.Whitworth, J. B., 104.Wiedenhagen, 230.Wieland, H., 128, 129, 130, 133, 136,136, 137, 138, 139, 140, 141, 143,184, 192.290.Wider, K., 212.Wilhelm, J. O., 55, 289.Wilke-Dorfurt, E., 49.Wilkins, H., 15.Willey, E. J. B., 53.Williams, J. M., 50.Williams, J. W., 216.Williams, L. T. D., 108.Williams, T. L., 336.Williamson, J. J., 233.Willimott, 243.Wilmet, M., 199, 207.Wilson, I. S., 149.Wilson, W. H., 243.Winchell, A. N., 310.Windaus, A,, 128, 129, 132, 133, 134,139, 141, 142, 143, 144, 148, 191,248.Winogradsky, S., 220.Winter, D. A., 33.Wintersteiner, 261.Wirz, K., 166.Wobbe, D. E., 339.Wohl, A., 64.Wokes, 243.Wolf, K. L., 14.Wolff, H., 208.Wolfmann, H., 67.Wollak, R,, 206.Wood, N. E., 86.Wood, W. A., 304.Woodman, H. E., 241356 INDEX OF AUTHORS’ NAMES.Wooldridge, W. R., 337.Worley, F. P., 334.Wormell, R. L., 67.Wright, L. O., 209.Wright, (Miss) W. M., 336.Wiinnenberg, E., 47.Wulf, 0. R., 321, 328.wurm, o., 202.Wyckoff, R. W. G., 283, 283, 287,300, 302, 304, 307.Yardley, (Miss) K., 303, 312.Yorston, F. H., 84.Yoshida, I., 200.Zachariasen, W., 289.Zahorka, A., 335.Zambonini, F., 69, 60,312,Zaunbrecher, K., 122.Zecher, G., 45.Zemplbn, G., 75, 79.Zetzsche, F., 203.Ziegner, H., 91.Zieler, H., 64.Zilva, 247.Zimmermann, 255, 256.Zintl, E., 40, 41, 216, 234.Zurcher, M., 217.Zuverkalov, D., 214.Zvjaginstsev, O., 59.313

ISSN:0365-6217    

DOI:10.1039/AR9272400343

出版商:RSC    

年代:1927

数据来源: RSC