INORGANIC CHEMISTRY.PROGRESS in the quantitative interpretation of the relative stabilities ofmetal complexes has been well maintained, and several important papers ofa general nature have appeared during the year.A large volume of work on diborane and borohydrides, carried out aboutten years ago, and awaited with much interest, has now been published.Some interesting new silicon hydrides have been prepared, e.g., S(SiH,),and P(SiH,),.There have been substantial developments in the chemistry of nitrogen,phosphorus, and sulphur, notably the discovery of the blue unstable com-pound " imine '' (NH), and the new allotropes, brown phosphorus and bothpurple and green sulphur; studies on the sulphur nitrides have progressedconsiderably and two new oxynitrides have been prepared.Progress in the chemistry of fluorine has included the preparation ofinteresting trifluoromethyl (CF,) derivatives of sulphur, phosphorus, andarsenic, and a new oxyfluoride of iodine (10,F).Greatly improved methods, using liquid ammonia, for the preparationof metal cyclopentadienyls have been used to obtain several new membersof this particularly interesting class of compound.Carbonyls, which arenow of much industrial importance, e.g., in connection with hydrof ormylationand carbonylation reactions, have received much attention, in particular thesubstitution of CO by other groups such as isocyanides, and the reactionsbetween carbonyls and organic compounds.Review articles have been published during the year on stratosphericair,l the action of nitric acid on metals,, protactini~m,~ the stereochemistryof nickeland other simple inorganic compounds,7 and inorganic chromatography.sAccurate heats of formation have been obtained for the oxides of tin,glanthanum, cerium,1° and hafnium,ll and vapour-pressure data for galliummetal,12 the iodides of boron and silicon,13 titanium tetrachloride l4 anduranium he~aflu0ride.l~ Other data are mentioned in later sections.Complexes.-A critical review of new and previously published data on thestability of complexes formed by bivalent ions of the first transition series hasshown that the Irving-Williams order Mn < Fe < Co < Ni < Cu > Zn holdsfor nearly all such complexes irrespective of the nature of the co-ordinatingligand and even of the number of molecules involved.This seems to be aand hexacovalent complexe~,~ the thermochemistry of oxidesF. A. Paneth, Bull. SOC. chim., 1953, 20, 1.E. Abel, 2. anorg. Chem., 1952, 271, 76.G. L. Miles, Revs. Pure Appl. Chem. (Australia), 1952, 2, 163. * R. S. Nyholm, Chem. Reviews, 1953, 53, 263.F. Basolo, ibid., 52, 459. L. Brewer, ibid., p. 1.L. H. Long, Quart. Reviews, 1953, 7, 134. R. A. Wells, ibid., p. 307.G. L. Humphrey and C. J. O'Brien, J . Amer. Chem. SOC., 1953, 75, 2805.l o E. J. Huber and C. E. Hollev, ibid., pp. 3594, 5645.l1 G. L. Humphrev, ibid., p. 2806.l2 R. Speiser and H. L. Johnston, ibid., p. 1469.l3 H. C. Andersen and L. H. Belz, ibid., p. 4825.l4 H. Schafer and F. Zeppernick, 2. anorg.Chew., 1953, 272, 274.l5 G. D. Oliver, H. T. Milton, and J. W. Grisard, J . Amer. Chem. Soc., 1953, '75, 282790 INORGANIC CHEMISTRY.consequence of the fact that the two parameters which serve as a measureof the electrostatic and covalent interactions respectively, vix., the reciprocalof the ionic radius and the second ionisation potential (M __t M2+), bothincrease monotonically throughout the series Mn to Cu. Since the processof co-ordination results in a decrease in formal charge, M2+ _+ MO, a metalof high second ionisation potential (it?., a cation of high electron affinity)will form more stable covalent complexes than one of lower ionisationpotential. The sudden drop in stability from copper to zinc is explainedin this way. Similarly the stability orders proposed by other workers toinclude, e.g., Zn, Cd, Pb, Mg, and other metals have no universal validityand even among a group of closely similar elements such as Mg, Ca, Sr, andBa the order of stability depends on the nature of the ligand. While com-plexes of ferrous iron with, e.g.ethylenediamine, salicylaldehyde, or glycineare about as stable as, or weaker than those of zinc and cadmium, its stronglycoloured diamagnetic complexes with 1 : 10-phenanthroline and 2 : 2’-dipyridyl are disproportionately stronger. This is explained by “ orbitalstabilisation” (see also ref. 317). Entropy and steric factors have alsobeen considered.16A quantitative but empirical relation has been discovered between theformation constant of a bivalent metal complex and the ionisation potentialof the metalJ17 and the methods available for computing successive formationconstants have been critically considered and improved.l8Steric influence on stability is shown by the relative stabilities of theferrous complexes of methyl-substituted 1 : 10-phenanthrolines. The 2 : 9-dimethyl compound does not form a ferrous complex, and/-\- the 2-methyl derivative [although a stronger base than />=< 2\ the parent (I)] forms a weak bis-complex, while (I) gives ‘‘d N-/ mainly the red tris-comple~.~~ Steric factors also influencethe stabilities of complexes formed by the hexadentate ligand 2o(NH2~CH2~CH,),N-CH2~CH2*N(CH2-CH2~NH,)2, which is only tetra- or penta-dentate to Cu, Zn, and Hg. Complex salts, considered to contain 7-, 8-,and 9-membered rings, have been prepared from cupric, silver, and mercuricperchlorates and NH,*[CH,] ;NH, (TZ = 4, 5, or 6).21The entropy factor has been studied in connection with several complexions.The heats of formation of the ions Cd(NH,),? +, Cd(NH,*CH,),++, andCden++ are almost identical, the greater stability of the (en) complex beingentirely due to the entropy factor, as has been suspected for some time.The same is true of the ions Cd(NH,),+ +, Cd(NH2*CH3)a+T, and CdThe six entropy changes in the successive reactions in the formation of theAlFa3- ion decrease with remarkable regularity ; heat and free-energydata have also been obtained.23Although potentiometric titration methods have been extensively used(I)H.Irving and R. J. P. Williams, I . , 1053, 3192; Analyst, 1952, 77, 813. c. L. Van Panthaleon Van Eck, &zc. Trav. chzm., 1953, 72, 50, 529.H. Irvingand H. S. Rossotti, J . , 1953, 3397; J. C. Sullivan and J. C. Hindman, J .Anter. Chein. SOG., 1952, 74, GO91 ; B. P. Block and G. H. Mclntyre, ibid., 1953, 75, 5667.Is H. Irving, 1%. J . Cabell, and D. H. Mellor, J., 1953, 3417.2o G. Schwarzenbach and P. Moser, Helv. C h i m Acta, 1953, 36, 551.2 1 P. Pfeiffer, E. Schmitz, and A. Bohm, 2. anorg. Chem., 1952, 270, 287.22 C . G. Spike and R. W. Parry, J . Amer. Chenz. SOC., 1953, 75, 27%.23 W. M. Latimer and U7. L. Jolly, ibid., p. 1548COATES AND GLOCKLING. 91to examine the relative stabilities of complexes, many particularly interestingcompounds are insoluble in water.Attempts to overcome this difficultyby the use of water-alcohol or water-dioxan mixtures complicate theinterpretation of potential measurements. Thermodynamic aspects of thisproblem have now been ~tudied.~4 The dissociation and stability constantsof fifteen p-diketones and their copper, nickel, and barium complexes havebeen compared in water-dioxan solution,25 and in one case an alcoholicsolution was compared with a water-dioxan mixture of the same dielectricconstant .26Tropolone forms metal complexes whose order of stability is similar tothat of other ligands ; several of its complexes are insoluble.27Solutions of complex anions free from metallic cations have beenobtained by the use of ion-exchange resins.Of the complex acids(H30i )3[Cr(C204)3]3-, only the last could be obtained in a crystalline state(blue needles). A similar procedure was used to prepare the salt[Co(NH,),] [Co(CO,),] from the green solution resulting from the oxidationof CO(II) salts in the presence of excess of alkali hydrogen carbonate.28Thermodynamic data have been obtained for the reversible formationof the bispen t anedionediaquomanganese (11 I) cation from t rispent anedione-manganese(~n).~~Formation constants have been determined for lead citrate complexes,30the Pb(N0,) + uranyl glycol late^,^^ complexes of copper and cobalt withphthalic, malonic, and other chelate acids,,, complexes of a series mainlyof bivalent metals with various p-diketone~,~~ digly~ylethylenediamine,~~nitrilotricarboxylic a ~ i d s , ~ 6 iminopropionic and aspartic acids,37 ethylene-diamine-acetic and -propionic acids,,8 and [CH2(OH)*CH2]2N*CH2-C02H.39A large number of metal-nicotine complexes has been prepared.40 Thebisthiosemicarbazones of a-diketones (NH,=CS*NH*N:CR), form highlycoloured, insoluble complexes with niany heavy metals [e.g., CU(II), Ni(iI),P ~ ( I I ) ] .~ ~Group 1.-The blue solution of lithium in methylamine decomposes at50-60" into lithium methylamide, LiONHCH,, and hydrogen. The amideis a white powder, almost insoluble in methylamine, and insoluble in etherand benzene. It reacts with various halides (even bromobenzene) givingN-methylamines, CH,*NHR.42 The series of ternary lithium nitrides hasH3O- [ co (N H3) 2 (No&]-, H30t [ Cr (NH3) 2 (SCN),]-, (H30+)3[CO( C204) 31 and24 L.G. Van Uitert and C. G. Haas, J . Amer. Chem. SOC., 1953, 75, 451.25 L. G. Van Uitert, W. C. Fernelius, and B. E. Douglas, ibid., pp. 455, 457.2 6 Idem, ibid., p. 3577.2 7 B. E. Bryant, W. C. Fernelius, and B. E. Douglas, ibid., p. 3784.28 T. P. McCutcheon and W. J. Schuele, ibid., p. 1845.29 G. H. Cartledgc, ibid., 1952, 74, 6015.30 M. Bobtelsky and B. Graus, ibid., 1953, 75, 4172.31 H. M. Hershenson, M. E. Smith, and D. N. Hume, ibid., p. 507.32 S. Ahrland, Acta Clzenz. Scand., 1963, 7, 485.33 hl. Bobtelsky and I. Bar-Gadda, Bull. SOC. chim., 1953, 20, 276.34 L. G. Van Uitert, W. C. Fernelius, and B. E. Douglas, J . Amer. Chem. SOC., 1953,3 5 A. K. Chakraburtty, N.N. Ghosh, and P. R%y, J . I n d i a n Chem. SOC., 1953, 30, 185.36 S. Chabereb and A. E. Martell, J . Amer. Chem. SOC., 1953, 75, 2888.37 Idem, ibid., 1952, 74, 6081.39 S. Chaberek, R. C. Courtney, and A. E. Martell, ibid., 1963, 75, 2188.40 C. R. Smith, ibid., p. 2010.42 R. Juza and E. Hillenbrand, ibid., p. 297.75, 2736, 3739, 3862.38 I d e m , ibid., p. 6228.41 G. Bahr, 2. anorg. Chem., 1953, 273, 32692 INORGANIC CHEMISTRY.been extended to some Group IV elements and now includes Li,SiN,, Li,TiN,,and Li,GeN,, as well as some oxynitrides, e g . , Li5TiN,,2Li,0.43The vapour-pressure equations of the chlorides of potassium, rubidium,and czsium have been obtained by measurement of rates of sublimationin a stream of nitrogen. The latent heats of sublimation, of interest inconnection with lattice energies, are KC1 50.2, RbCl 46.4, and CsCl 44.1k~al./mole.~~ The systems NaC1-SrSO, (or BaSO,) resemble NaCl-CaSO,in not forming either solid solutions or double salts, but there is completeliquid mi~cibility.~~A recent measurement of the vapour pressure of copper has resulted ina new value, 81-08 kcal./g.-atom, for the latent heat of vaporisation atSolutions of cuprous chloride in concentrated hydrochloric acid absorbacetylene without colour change ; the acetylene probably retains its hydro-gen, and the addition compounds appear to contain one molecule of acetyleneand one atom of copper.Neutral solutions of cuprous chloride in alkalichlorides absorb acetylene with the formation of a bright yellow colour;in this case copper appears to be substituted for hydrogen, giving an acetylide.The species CuC1, -, CuCl,=, C,H,,Cu+, C,H,,CuCl, and C,H,,CuCl,- havebeen identified in the colourless solutions, and their formation constantsmeasured.47A series of copper(rr) pyrophosphates, [CU(P,O~),]~-, [CUP,O,]~-,[CU,P,O,]~, and [Cu,P,O,]++, has been detected by light-absorption experi-m e n t ~ .~ * Similar methods revealed the complex ion [CuP,O, en],- insolutions containing CU(II), pyrophosphate, and eth~lenediamine.~~Crystalline salts containing the anions AgX,-, PbX,-, and PbX42-[X = halogen] are reported to be formed from the appropriate halides andthe bisethyIenediaminecopper( 11) cation in the presence of sodium or ammon-ium chloride.The red Me,N*CH,*CH,*OH,CuCl, and yellow [Me,N*CH,*CH,( OH)],CuC14choline-copper( 11) complexes are unstable in water, but when prepared inethanol are better catalysts than copper sulphate or chloride for certainautoxidation rea~tions.~l Copper(r1) forms only a 1 : 1 complex withtriethanolamine, as shown both by spectrophotometry and transport-number experiment^.^,Tetramminocopper(rr) sulphate, Cu(NH,),SO,, has been used for the pre-paration of some copper(I1) complexes, e.g., with l-benzeneaz0-2-naphthoI.~~The dimer of cyclooctatetraene of m.p. 41.5" forms two compounds, withone and two mols. respectively of silver nitrate. Another dimer, m. p.38.5", forms a more stable 1 : 1 complex which appears to be one of the moststable silver-olefin compounds. 540" K.46These salts are unstable to boiling water.5043 R.Juza, H. H. Weber, and E. Meyer-Simon, 2. anorg. Chenz., 1953, 273, 48.44 W. D. Treadwell and W. Werner, Helv. Chinz. Acta, 1953, 36, 1436, 1445.45 J. By6 and J. Holder, Bull. SOL chim., 1953, 20, 399.46 H. N. Hersh, J . Anzer. Chew. Soc., 1953, 75, 1529.4 7 R. Vestin and C. Lofman, Acta Chenz. ScaNd., 1953, '7, 398, 745.48 J. I. Watters and A. Aaron, J . Amer. Chenz. SOC., 1953, 75, 611.49 J. I. Watters and E. D. Loughran, ibid., p. 4819.50 C. M. Harris and H. N. S. Schafer, J . Proc. Roy. SOC. N.S.W., 1952, 85, 148.51 P. L. White, D. M. Hegsted, and J. Meyer, J . AmeY. Chem. SOC., 1053, 75, 2352.52 J. M. Bolling and J. L. Hall, ibid., p. 3953.53 I.Kalugai, Bull. Research Council Israel, 1952, 1, No. 4, 96.54 Mi. 0. Jones, J., 1953, 2036COATES AND GLOCKLING. 93Contrary to previous claims, silver perchlorate has been shown not toact as a Friedel-Crafts type of catalyst. In those instances where there isapparent activity, it is due to the presence of free perchloric acid or to meta-thetical formation of an acyl per~hlorate.~~The relative formation constants of the silver complexes with a varietyof di-, tri-, and tetra-amines have been interpreted quantitatively on thebasis of only two collinear co-ordination positions on the silver ion. In veryfew instances was there evidence of further ~o-ordination.~~ The thiocyanategroup, however, seems to combine further, since formation constants havebeen reported for the ions Ag(SCN),-, Ag(SCN),=, and Ag(SCN),3-.57Group 11.-The heat of formation of beryllium oxide has been measuredagain by modern methods (AH,, = -143.1 & 0.1 k~al./mole).~~ Themonoclinic form of basic beryllium acetate, previously obtained by conden-sation from the vapour, can also be prepared by crystallisation from hottetralin.59The basic magnesium chlorides have been further studied,60 both bythermal decomposition of hydrated magnesium chloride and by crystallisationfrom solutions of magnesium oxide in concentrated magnesium chloride, thelatter depositing crystalline MgC1,,3Mg(OH),,8H20. A " Werner-complex "structure (11) was assigned to this salt, but the Reporters consider (111) tobe a more likely formula.The solutions of beryllia in aqueous berylliumsalts are probably similarly constituted.H H HH H H' O H j OH2(11) (111)About a third of the mzgnesium ions in the layer lattice of the compoundMg,((CH,) 9N,),(Fe(CN) 63,,24H20, which is easily prepared, may be exchangedwith a variety of small inorganic ions.61The heats of solution of calcium metal and calcium iodide in liquidammonia a t -33" have been measured; AH = -19-7 and -62.8 kcal.,respectively. For the reaction between calcium metal and the ammoniumion, AH = -99.3 kcal. From these data the value AH = -79.7 kcal. hasbeen calculated for the reaction2e-(NH,) + 2NH,+(NH,) = 2NH,(l.) + H2(g.)which agrees with the result obtained from the thermochemistry of thealkali metals in liquid ammonia, and indicates that calcium dissolves asCa++ ions rather than Ca+ or Ca2++ as had previously been suggested.Thestandard entropy of the calcium ion in liquid ammonia has also beenmeasured.625 5 13. Burton and P. F. G. Praill, J., 1953, 837.6 6 G. Schwarzenbach, Helv. Chim. A d a , 1953, 36, 23.5 7 G. C. B. Cave and D. N. Hume, J . Amev. Chem. SOC., 1953, 75, 2893.5 8 L. -4. Cosgrove and P. E. Snyder, ibid., p. 3102.59 H. D. Hardt and H. Hendus, 2. azorg. Chem., 1952, 270, 298.6 o G. Wehner, ibid., 1963, 272, 201.61 A. Weiss, A. Weiss, and U. Hofmann, ibid., 1953, 273, 129.62 S. P. Wolsky, E. J. Zdanuk, and L. V. Coulter, J . Amer. Chem. Soc., 1952, 74,618694 INORGANIC CHEMISTRY.A new structure has been proposed for the red peroxychromate of calcium,viz., Ca,Cr20,,,10H20.63As an example of the effect of lattice defects on colour it is noteworthythat red crystals of barium oxide up to 2 mm.x 1 cm., containing about0.1% excess of barium have been grown in a vacuum furnace atThe hydrazine complexes of zinc have been studied polarographically, 65and formation constants have been obtained for zinc-pyridine complexes.66Experiments on the dissociation equilibria of ammines of mercuricchloride and iodide, of similar pyridine complexes, and of " infusible whiteprecipitate " suggest the formula Hg0,HgC12,2NH, for the latter. Itwould seem to be formed by the partial hydrolysis (during preparation) of" fusible white precipitate," HgC1,,2NH,.67Solid solutions of the two mercuri-iodides Ag,HgI, and Cu,HgI,, whichchange colour on heating, have been prepared by simultaneous precipitation.The lattice parameters, colours, and colour-transition temperatures havebeen measured as a function of composition.68Group 1 I I .T h e structures of t e t r a b ~ r a n e , ~ ~ B,HIo, and the unstablepentaborane, 70 B5H,,, have been determined by improved and elaboratemethods. Of the higher hydrides of boron, only B 6 H I o remains of unknownstructure. All the hydrides examined, except diborane, offer valencydifficulties since they contain boron apparently bonded to five or six otheratoms.The dissociation of diborane to two molecules of boriute, BH,, probablyoccurs in many reactions of the former, but the presence even of a trace ofborine has never been detected in diborane.Thermodynamic calculationson the equilibrium B2H6 + 2BH3 indicate a degree of dissociation of 1.6 Xl.0-5 a t 155' and 1 atm., and under these conditions pyrolytic decomposi-tion is rapid. The heat of the reaction, AH2,30h: = -32 -J-- 4 kcal./mole ofdiborane, was estimated by comparing the heats of reaction of trimethyl-amine with B2H6, B,H2Me4, and BMe,. The entropy change (AS30,o~ =33.8 e.u.) was calculated from spectroscopic data and the known moleculardimensions of diborane, a planar structure being assumed for BH, and itsforce constants being estimated by Badger's rule. 71The order of the homogeneous vapour hydrolysis of diborane 72 is 312,first order with respect to water and 1/2 with respect to diborane; this isconsistent with the mechanism :B,H, 2BH,- +BH, + H,O -A H,B*OH, 4 BH,.OH + H,BH,*OH + H,O BH,(OH)*&H, __t BH(OH), + H,-BH(OH), + H,O BH(OH),~H, -+ B(OHJ, + H,63 J.B. Martinez and C. Porter, Anal. SOC. Quim., 1952, 48, B, 879 (Chem. Abs.,65 R. L. Rebertus, H. A. Laitinen, and J. C. Bailar, ibid., p. 3051; see also Ann.6 7 D. R. GIasson and S. J. Gregg, J.. 1953, 1493.68 L. Suchow and P. H. Keck, J . Amer. Chew. SOC., 1953, 75, 518.69 C. E. Nordman and W. N. Lipscomb, J . Chew. Phys., 1953, 21, 1856.70 L. R. Lavine and W. N. Lipscomb, ibid., p. 2087.71 S. H. Bauer, A. Shepp, and R. E. McCoy, J . Amer. Chent. SOC., 1953, '45, 1003. '* H. G. Weiss and I. Shapiro, ibid., p. 1221.1953, 47, 5837).Reports, 1952, 49, 95.64 G.G. Libowitz, J . Amer. Chern. SOC., 1953, 75, 1501.6 6 C. J. Nyman, J . Amer. Chern. SOC., 1953, 75, 3575COATES AND GLOCKLING. 95Diborane reacts with hydrazine or NN-dimethylhydrazine in ether at--80", giving white crystalline compounds BH3*6HR*&HR-BH, (R = Hor Me). Pyrolysis of the hydrazine compound gives a solid product, butthat of the dimethyl derivative gives a fairly volatile liquid, probablyBH,*NMe*NMe*BH,, apparently monomeric, which polymerises at aboutDiborane forms a co-ordination compound H,B-PHMe,, with dimethyl-phosphine ; this loses hydrogen at 150" forming mainly a trimer (Me,P*BH,),with some higher polymers. Similar compounds, e.g., (Me,P*BMe?!,, werealso prepared and ail are remarkable for their high thermal stability andchemical inertness, in contrast to most B-N compounds, e g ., (Me,N*BH,),.This difference is attributed to the use of 3d orbitals by phosphorus for P-Bbonding, an effect not possible with nitrogen.74Several co-ordination compounds between borine and trialkyl-phos-phines, -arsines, and -stibines have been prepared, and their reactions withhydrogen chloride studied ; in some instances borochlorides, containing theBC1,- ion, appear to be f0rmed.7~Although sodium borohydride has been known for some years and hasbeen, available commercially, descriptions of its preparation have onlyrecently appeared.76 Investigations at the University of Chicago into thepreparation of diborane, borohydrides, and similar substances since 1941have been summarised in one paper.'7 Experiments on the arc method forpreparing diborane from boron tribromide and hydrogen have shown thatdiborane can be purified from hydrogen bromide by reaction with a littlepyridine, and from other volatile impurities by conversion into the pyridine-borine complex followed by regeneration of diborane from the latter.'*Methyl borate reacts exothermically with sodium hydride : 79NaH + B(OMe), = Na[BH(OMe),]Sodium trimethoxyborohydride reduces carbon dioxide to sodium formate,Na[BH(OMe),] + CO, = H*CO,Na + B(OMe),, and its unstable aqueoussolution is a powerful reducing agent.Sodium hydride or lithium hydridereact with BF,,OEt, in two stages :600.73 - +LiH -+ Bl?,,OEt, = LiBHF, f OEt,3LiBHF, + GF,,OEt, = 4B,13, + 3LiBl7, + OEt,which provide a convenient method for the preparation of diborane.80 Thelatter may also be obtained by the reactionGNa[BH(OMe),] + 8BF,,OEt, = B,H, + GNaBF, + GB(OMe), + 80Et,Lithium hydride alone does not absorb diborane, but reaction is rapid inether suspension, with the formation of LiBH4,0Et276 (ether dissociationM. J.Steindler and H. I. Schlesinger, J . Amer. Chem. SOG., 1953, 75, 756.74 A. B. Burg and R. I. Wacner, ibid., p. 3872.75 F. Hewitt and A. K. Holyiday, J . , 1953, 530.76 G. Wittig and P. Hornberger, Annale?z, 1952, 577, 11; 2. Naturforsch., 1951,8, b, 225; H. I. Schlesinger, H. C. Brown, H. R. Hoekstra, and L. R. Rapp, J . Amer.Chem. SOG., 1953, 75, 199;. H. I. Schlesinger, H. C. Brown, and A. E.Finholt, ibid., p.205,r S H. I. Schlesinger, H. C. Brown, B. Abraham, N. Davidson, A. E. Finholt, R. A.Lad, J. Knight, and A. M. Schwartz, ibid., p. 191.70 H. C. Brown, H. I. Schlesinger, I. Sheft, and D. M. Ritter, ibid., p. 192.7 7 I d e m et al., ibid., p. 186.€1. I. Schlcsinger, 13. C. Brown, J. R. Gilbreath, and J . J . Katz, ibid., p. 10596 INORGANIC CHEMISTRY.pressure 10 mm. at 0'). Sodium hydride, however, does not react withdiborane, but sodium borohy dride is obtained from the trimethoxyboro-hydride by the very rapid reaction2Na[BH(OMe),] + B,H, = 2NaBH, + 2B(OMe),,or from sodium tetramethoxyborohydride :3NaB(OMe), + 2B,H, = 3NaBH, + 4B(OMe),Likewise potassium borohydride was prepared from KB (OMe),. Sodiumborohydride, stable to nearly 400" and in air to 300", dissolves in cold waterwith slight decomposition and can be crystallised as the hydrate NaBH,,ZH,Owhich can be dehydrated without loss of hydrogen.It is stable in the weaklyalkaline solution produced by its initial partial hydrolysis :NaBH, + 3H,O = NaH,BO, + 4H2but is rapidly decomposed by heat, acids, or transition-metal ions, notablyCo2+.S1 In contrast to lithium borohydride it is insoluble in ether anddioxan, but dissolves easily in ammonia, ethylenediamine, and the lowerprimary amines, isopropylamine being a convenient solvent for its extraction.Sodium borohydride reacts vigorously and quantitatively with BF,,OEt, :3NaBH, + 4BF,,OEt, = 2B2H, + 3NaBF, + 40Et,This reaction is a very convenient method for the preparation of smallquantities of diborane and is regarded as an example of the displacementof a weak acceptor (BH,) or " acid " by a stronger (BF3).76Sodium borohydride may be obtained without the use of diborane, themost satisfactory method being the reaction between sodium hydride andmethyl borate at 250-270" :4NaH + B(OMe), = NaBH, + 3NaOMeThe product is extracted with isopropylamine.Lithium borohydride canbe prepared similarly. Less satisfactory, but very interesting, methods arethe thermal disproportionation (- 230") of sodium trimethoxyborohydride,4Na[BH(OMe),] = NaBH, + 3NaB(OMe),the treatment of methyl borate and sodium with hydrogen under pressure4Na + 2H2 + B(OMe), = NaBH, + 3NaOMeand the remarkable solid reaction in which sodium hydride and boric oxideare ground together at 330-350''for 2 0 4 8 hours,4NaH + 2B,O, = NaBH, + 3NaB0,Aluminium borohydride is now most conveniently obtained from lithiumborohydride, which reacts more rapidly than the sodium salt , and aluminiumchloride : 82Beryllium borohydride is prepared similarly.Lithium borohydride isconveniently obtained from the sodium salt and lithium chloride in iso-propylamine solution, sodium chloride being insoluble in this solvent. A81 H. I. Schlesinger, H. C. Brown, A. E. Finholt, J. R. Gilbreath, H. R. Hoekstra,and E. K. Hyde, J . Amer. Chem. SOC. 1953, 75, 215.82 H. I. Schlesinger, H. C. Brown, and E. K. Hyde, ibid., p. 209.(2500) J3LiBH, + AICl, = Al(BH,),+ + 3LiCCOATES AND GLOCKLING. 97complex LiBH,-dioxan is more convenient to handle than LiBH, itself,being less hygroscopic.83 The storage of aluminium borohydride is danger-ous, not only on account of the spontaneous inflammability of its vapour,but also because of the slow generation of hydrogen and consequent pressureincrease. The decomposition is retarded by the accumulation of a reactionproduct of unknown constitution.82The preparation and properties of uranium(1v) borohydride 84 and someof its B-methyl derivatives s5 have been described in detail.The borazens, R,B*NR,, are of considerable interest since they are oftenmonomeric and appear to achieve co-ordination saturation by a substantialdegree of double bonding (R,B = NR,).The Raman spectra of Me3B*iH3,8s Me,B*NH, and Me,B*NMe, 87 giveB-N force constants appropriate to a single bond in Me3B-NH, and todouble bonds in the two borazens.The dipole moments of Me,B*NH,(4.15 0.06 D), Me36*&Me, (3-92 rJt 0.03 D), Me,B*NH, (1.47 & 0.06 D),and Me,B*NMe, (1.40 & 0.03 D) have now been measured. Corrected forB-C and N-H (or N-C) moments, the B-N bond moments are about 26-3 Din the borazan series and about zero in the borazens. The large moments tobe expected from the co-ordination formula- +-- +- -R,B - NR, and R,B = NR,are evidently reduced very considerably by unsymmetrical electron sharingin the sense B + N owing to the electronegativity difference betweenboron and nitrogen. Since double bonds are so much more polarisable thansingle bonds the effect is, as observed, greater in the borazen than in theborazan series.Useful experimental methods for the preparation of benzenesolutions of air-sensitive substances are also described. 88Specimens of boron carbide with formulz between B,C and B,C havebeen prepared and subjected to X-ray analysis. The hardness diminisheswith increasing boron content.89Co-ordination compounds between boron trifluoride and donor moleculescontaining oxygen have been the subject of some careful physical and electro-chemical studies.s0 Methanol being taken as a typical donor, the 1 : 1complexes are represented as- +2F,B*OHMe [MeOH,BF,]+[MeOBF,] -and the 1 : 2 complexes as [MeOH,]+[MeOBF,]-. Consideration of thereduced conductivity (molar conductivity X viscosity) of numerous borontrifluoride complexes, and comparison with various fused salts, indicatesthat the degree of self-dissociation is about 10% in complexes with water,alcohols, and acids, and 0.1% for esters, ethers, and tertiary amines.9183 R.Paul and N. Joseph, Bull. Soc. chim., 1953, 20, 758.8 4 H. I. Schlesinger and H. C. Brown, J . Amer. Chem. SOC., 1953, 75, 219.8 5 H. I. Schlesinger, H. C. Brown, L. Horvitz, A. C . Bond, L. D. Tuck, and A. 0.8 7 Idem, ibid., p. 133.8s R. D. Allen, J. Amer. Chew. SOC., 1953, 75, 3582.90 N. N. Greenwood and R. L. Martin, J., 1953,751,757.Walker, ibid., p. 222. 8 6 H. J. Becher and J. Goubeau, 2. anorg. Chem., 1952, 268, 1.88 H. J. Becher, ibid., 1952, 270, 273.'l Idem, ibid., p. 1427.REP.-VOL.L 98 INORGANIC CHEMISTRY.Pure lithium fluoroborate can be obtained from anhydrous Li,CO, andBF,,OEt, in dry ether.92The lowest chloride of boron, B4C14, has an electron-deficient structure.Each molecule consists of a very slightly irregular tetrahedron of boronatoms (mean B-B bond order Q ) , each boron being linked to a chlorineatom by a single bond.93 The '' dichloride " B,Cl, has an ethylene-likebut non-planar structure (symmetry V d ) .94 Boron trichloride and di-n-butyl sulphide form a stable 1 : 1 complex from which the sulphide can bedisplaced by ~ y r i d i n e . ~ ~Boron halides and alkylboron halides react readily with silicic acid andesters of the type R,LSi(OR')4-n, exchanging alkoxy-groups and halogenatoms,96 eg.,2R,SiOR' + BBr, = SR,SiBr + BrB(OR'),Several new boron sulphides have been prepared from boron halides andhydrogen sulphide.Excess of the latter gives metathioboric acidBX, + 213,s = SBSH + 3HXwhich has been obtained in di- and tri-meric forms (IV) andPH(IV) HS-B,S,B-SH HS-B /s-B\s\S-B(Excess of boron halide, on the other hand, gives halosulphides (BSX),,which disproportionate on standing : (BSX), __t BX, + B&98Evidence has been presented for the formation of phenyl radicals by thedecomposition of chloroform solutions of salts of the BPh,- anion; e.g.,diphenylmercury is formed when mercury is present. The ammoniumsalt NH,+BPh,- decomposes at 110-120" into benzene and iH,*BPh,.99The yellow addition compound between sodium and triphenylboron isdiamagnetic and believed to be Na2++ (Ph,B-BPh,)=.lOOEbullioscopic measurements show that aluminium hydride (from AlCl, +LiAlH,) is monomeric in ether, with which it is doubtless co-ordinated.The slow precipitation of an ether-insoluble polymer may be prevented byaddition of trimethylamine, which forms the more stable complexesAlH,,NMe, (m.p. 76") and AlH,(NMe,), (m. p. 95"). Both are monomericin ether and sufficiently volatile to be sublimed easily. The 1 : 2 compoundwould appear to be an example of a complex with the rare co-ordinationnumber five.lol92 I. Sliapiro and H. G. Weiss, J . Anzer. Chewz. SOC., 1953, 75, 1753.93 M. Atoji and W. N. Lipscomb, J . Chew. Phys., 1953, 21, 172.s4 M. J. Linevsky, E. R. Shull, D. E. Mann, and T.Wartik, J . Anzer. Chem. SOC.,06 E. Wiberg and U. Kriierke, 2. Naturforsch., 1953, 8, b, 608.9 7 E. Wiberg and W. Sturm, ibid., p. 530.99 G. A. Razuvaey and T. G. Brilkina, Doklady Akad. Nauk S.S.S.R., 1952, 85, 815.1953, 75, 3287. 95 M. F. Lappert, J.. 1953, 2784.98 Idem, ibid., p. 529.100 T. Li Chu, J . Amer. Chem. Soc., 1953, 75, 1730.lol E. Wiberg, H. Graf, and R. Us6n, 2. anorg. Chenz., 1953, 2'72, 221COATES AND GLOCKLING. 99Dimethylaluminium hydride has been prepared by a far more convenientmethod than the original gas-discharge process :(M = B, Al, or Ga). It is a very viscous, colourless liquid (v.P. 2 mm. at25"). The degree of association of the vapour varies between 2.5 and 2from 83" to 167", and the hydride is trimeric in isopentane solution at 2Oo.lo2The salts LiAlEt, and NaAlEt, have been prepared from Et3A1,0Et2and EtLi or EtNa.Aluminium ethylsulphinate (triethylsulphonylalumin-ium), Al(SO,Et),, results from Et3A1,0Et, and S0,.lo3A detailed study of the hydration and hydrolysis of aluminium bromideas vapour, solid, and combined with ether has shown that the primaryreaction involves hydration to Br3A1,0H2, which, if hydrolysis is avoided,is followed by formation of the octahedral complex Br,Al(H,O),. Furtherhydration then occurs by progressive replacement of the bromine atoms bywater molecules, giving finally [A1(H20]6)3+3Br- which is stable at roomtemperature and catalytically inactive. The results suggest that the pro-moter effect of aqueous halogen acids on aluminium halides in Friedel-Crafts reactions may be due to water rather than to hydrogen halide.lo4The preparation and manipulation of pure aluminium bromide has also beendescribed in connection with experiments on this compound as a solvent.Solvolytic reactions are discussed in terms of the ionisation equilibria : lo5LiAlH, + Me,M = Me,AlH + LiMMeH,AlBr, AlBr,+ + Br-AlBr, + Br- 'p- AlBr,-Conductivity studies on aluminium bromide and stannic chloride in thionylchloride solutions containing pyridine indicate the presence of the ions[py AlBr2]+, [pyz A1Br2]+, and [py SnC13]+.lo6The halogen-exchange reaction between HC1 and AlBr, goes as far asAlBrCl,, whereas HBr and AlCl, give A1Br3.107Aluminium chloride and bromide form complex salts with hydrazine, ofthe type (N2H5),A1X6,6H,O.It is suggested that AlCl,3- or AlBr63- ionsare present in these salts.lo8A study of the thermal decomposition of alumina trihydrate (Gibbsite)by X-ray and thermal analysis indicates two routes, one through the mono-hydrate (boehmite) and the other directly to the virtually anhydrous X-alumina.lo9 Data on the hydration of alumina have been reviewed andsupplemented.The reduction of anhydrous rare-earth chlorides with calcium is a satis-factory method for preparing the metals in most cases, but samarium andytterbium are reduced only to the bivalent state. Metallic samarium andytterbium have recently been obtained by distillation (from a tantalumcrucible) of a mixture of the oxide and lanthanum metal, since both metalsl o 2 T.Wartik and H. I. Schlesinger, J . Amer. Claem. SOL, 1953, 75, 835.E. B. Baker and H. H Sisler, ibid., p. 5193.lo* F. Fairbrother and W. C. Frith, J . , 1953, 2975.lo5 G. Jander and W. Zschaage, 2. anorg. Chem., 1953, 272, 53.lo6 L. E. D. Pease and W. F. Luder, J . Amer. Chewz. SOL, 1953, 75, 5195.lo' J. D. Corbett and N. W. Gregory, ibid., p. 5238.lo* W. Pugh and M. C. B. Hotz, J., 1953, 2493.109 J. F. Brown, D. Clark, and W. W. Elliott, ibid., p. 84.110 H. Ginsberg and M. Koster, 2. anorg. Chem., 1952, 271, 41100 INORGANIC CHEMISTRY.are considerably more volatile than lanthanum. Pure samarium meltsbetween 1025" and 1050", its density is 7.53, it is very soft and does notreadily tarnish in the air.lll Samarium metal can also be obtained fromthe anhydrous bromide and barium.112Techniques for the separation of rare-earth elements with the help ofethylenediaminetetra-acetic acid (" enta ") have been improved.lI3 Classicalmethods continue to be developed, e g . , for erbium salts,114 as well as thenewer processes. Gadolinium oxide in 95%. purity has been obtained on akilogram scale by countercurrent liquid-liquid extraction with tributylphosphate and nitric acid.l15Detailed optical data have been recorded for many hydrated rare-earthbromates,l16 and solubility and conductivity data for some rare-earth saltsin basic solvents ( e g . , morpholine) .l17 Thermodynamic data have beenobtained for the reversible hydrolysis of samarium( 111) and gadoliniumchlorides by water vapour,ll* and for the dissociati on of cerium(II1) sulphate1l9in aqueous solution, CeSO,+ S Ce3+ + SO,=.Cerium(II1) cyanamide, Ce2(CN2),, has been obtained from CeO,, NH,,and HCN at 600-880" ; the colour varies from yellow to dark green, perhapson account of lattice defects.120 Solutions of pure 12-molybdoceric(1v) acidhave been prepared by the use of an ion-exchange resin; the acid con-tains eight replaceable hydrogen ions, and the dimethylammonium salt(Me2NH),CeMo120,2,20H20 has been obtained.It is suggested that acentral CeO, octahedron is surrounded by MOO, octahedra.121Trimethylgallium forms unstable 1 : 1 co-ordination compounds withmethyl cyanide and acetone, but donor molecules con-taining reactive hydrogen give methane and dimerichie,Ga- - GaMe, products.Thus methanol gives (VI). The relativestability of these co-ordination compounds has beenMe (VI) investigated by reaction with trimethylamine ; whileMe/9\\6/(VI) does not react, the sulphur analogue is split reversibly :(Me,Ga.SMe), + 2NMe3 e- 2Me,Ga(SMe) -;Me,.A volatile acetylacetone complex, Me2Ga(C,H702), and a salicylaldehydederivative. Me,Ga*O*C,H,*CHO, have also been described. 122Raman spectra indicate that bath solid and liquid gallium(II1) chlorideare composed of Ga2CI, molecules with a bridge structure.l23The hydrolysis constant, K = [In0H++][HT]/[In3+], is 1.40 x 10-4 at25" from pH data.lZ4111 A. H. Daane, D. H. Dennison, and F. H. Spedding, J . Aulzer. Chem. Soc., 1953,113 E.J. Wheelwright and F. H. Spedding, ibid., p. 2529; J. K. Marsh, J . , 1952,115 B. Weaver, F. A. Kappelmann, and A. C. Topp, J . Amer. Chem. Sac., 1953, 75,1 1 7 T. Moeller and P. A. Zimmerman, J . Amer. Chem. SOC., 1953, 75, 3940.118 C. W. Koch and B. B. Cunningham, ibid., p. 796.119 T. W. Newton and G. M. Arcand, ibid., p. 2449.120 H. Hartmann and G. Dobek, Z . anorg. Chem., 1953, 271, 138.121 L. C. W. Baker, G. A. Gallagher, and T. P. McCutcheon, J . Anzer. Clzektz. Soc.,123 H. Gerding, H. G. Haring, and P. A. Renes, Rec. Trav. &him., 1953, 72, 78.124 L. G. Hepler and 2. 2. Hugus, J . Amer. Chem. Soc., 1953, 74, G115.75, 2272.4804.3943.112 E. I. Onstott, ibid., p. 5128.114 0. M. Hilal, 2. amrg. Chem., 1953, 278, 241.116 H.Schumann, Z. anorg. Chem., 1952, 271, 29.1953, 75, 2493. lZ2 G. E. Coates and R. G. Hayter, J., 1953, 2519COATES AND GLOCKLING. 101I n an investigation of the equilibrium In,O, + 3H, & 21n(l.) +3H,O(g.), leading to the thermodynamic constants of indium(II1) oxide,X-ray examination indicated absence of any oxide other than In,0,.125Solutions of indium(II1) chloride acquire reducing properties when shakenwith metallic indium and filtered. Quantitative investigation of this effecthas provided equilibrium constants for the formation of In+ and In2+ ionswhich can exist only at low concentration in solution.lZ6 The direct oxid-ation of thallous sulphide has been followed by X-ray diffraction, which hasshown that T1,O and T1,S,03 are the primary oxidation p r 0 d ~ c t s .l ~ ~From the variations of the thallous-thallic exchange rates with salt andacid concentration it seems likely, but not definitely proved, that the simpleTP+ ion participates in the reaction.lZ8Group 1V.-Measurements of the heat of sublimation of graphite, aquantity of great interest in connection with bond energies, have been com-plicated by uncertainties involving the accommodation coefficient forevaporation, and the identity and relative a mounts species. By using a mass spectrometer to identify atomic and molecularspecies, the heat of sublimation of graphite to 3P carbon atoms has beengiven the value 178.5 & 10 kcal./mole at 0" K,lZ9 a value which supports thehighest spectroscopic result of 170 kcal.Carbon atoms do not normally act as acceptors in the formation of co-ordination compounds.Since bonding to electronegative atoms enhancesacceptor properties, carbonyl chloride should be one of the most suitablecompounds to examine with the object of preparing a co-ordination compoundof carbon, and in fact a 1 : 1 complex is formed with trimethylamine : l 3 Oc1 Y1 +c1 c1O=C< + NMe, + OT-NMe,The complex decomposes about room temperature with evolution of methylchloride : 6CC12*6Me, _+ Me,N-COCl + MeC1.A highly reactive form of silicon has been prepared by the reactionSCaSi, + 2SbC1, - 6Si + 2Sb + 3CaC1,; with water it forms SiO, andhydrogen quantitatively in a few minutes. The silicon is considered toform a network of six-membered rings.131 Compounds of silicon withselenium and tellurium, having the composition SiSe, and SiTe,,132 have beenprepared from the elements at 1050" ; SiTe, crystallises in red plates with thecadmium iodide structure, and at 1200" forms the compound SiTe.TheSi-Te distance of 3.04 A in SiTe, corresponds more closely to metallic thanto ionic bonding.lS3Silica is noticeably attacked by hydrogen chloride in the presence of fusedalkali chlorides at lOOO", a reaction ascribed to the formation of unstable125 M.F. Stubbs, J. A. Schufle, and A. J. Thompson, J . Amer. Chenz. SOC., 1052,74,6201.126 L. G. Helper, 2. 2. Hugus, and W. M. Latimer, ibid., 1953, 75, 5652.12' B. Reuter and A. Goebel, 2. anorg. Chem., 1953, 271, 321.128 R. W. Dodson, J . Amer. Chem.Soc., 1953, 75, 1795.12Q W. A. Chupka and M. G. Inghram, J . Chem. Phys., 1953, 21, 371.130 J. Goubeau and G. Winkelmann, 2. anorg. Chem., 1953, 271, 235.131 H. Kautsky and L. Haase, 2. Nafurforsch., 1953, 8, b, 45.132 A. Weiss and A. Weiss, ibid., p. 104.133 Idem, 2. anorg. Chem., 1953, 273, 124102 INORGANIC CHEMISTRY.chl~rosilicates.~~~ A new method for the preparation of solutions of thevery unstable silicic acid has been devised, based on the reaction betweenpowdered hydrated sodium metasilicate and acid-treated cation-exchangeresin at 0". Silicate ions are probably monomeric in crystalline hydratedsodium metasilicate and in solutions of sodium orthosilicate.135 Startingfrom analcite (Na2O,A1,O3,4SiO2,2H2O), which is readily synthesised, anumber of other mineral silicates have been prepared by hydrothermalreactions.Several mineral-type silicates not found naturally have alsobeen prepared and ~haracterised.~,~Considerable interest has been shown in the chemistry of silicon halidesand related compounds. Partial hydrolysis of Si2C1, results in the formationof oxychlorides, of which (Si,C15)20 and Si2C1,*O*Si2C1,*O*SiC13 have beenis01ated.l~~ Ammonium halides and Si,C16 form polymeric nitrogen-con-taining compounds as well as SiCl, and SiHCl,, whilst trimethylammoniumchloride gives SiC1, and (SiCl,),. Both reactions are initiated by the freebase.138 Trichlorosilicon acetate, b. p. 130" (extrap.), has been preparedfrom SiC1, and anhydrous sodium acetate ; it readily disproportionates intoSiC1, and Si(OAc), with simultaneous formation of acetyl chloride andpolymeric products.139Ethylsilanes decompose at a measurable rate at 440-460" and are onlyslightly more resistant to decomposition than ~ i 1 a n e . l ~ ~ These reactions arecomplicated but are of interest in connection with the reaction between SiH,and olefins giving various alkylsilanes. 141 Hydrolysis of dimethoxydi-methylsilane by boiling water has led to the isolation of crystalline dimethyl-silanediol, Me,Si(OH),, m. p. 101" (decomp.). This compound, which maybe regarded as the parent body of the silicone polymers, can be kept withoutdecomposition only by cooling in liquid nitrogen; it condenses to a polymereven by the catalytic action of alkali from glass and is also very sensitiveto acids1,,The Raman spectrum of methoxytrichlorosilane, which is stable up to--500", has been r e ~ 0 r t e d . l ~ ~In view of the relative rarity of the co-ordination number five (see p. 98),a study of the SiF,-NMe, system is of some interest since it reveals compoundsSiF,,NMe, and SiF4(NMe3)2, both of which are almost wholly dissociated as~ a p 0 u r .l ~ ~Complex volatile silyl compounds, eg., P(SiH,),, P(SiH,),I, and P(SiH,)I,,result when SiH,I reacts with phosphorus or arsenic a t room temperatureand with antimony at higher temperatures. From the reaction betweenSiH,I and excess of sulphur the compounds SiH,-SH, (SiH,),S, and impurenon-volatile SiSI, have been is01ated.l~~ A number of substituted siloxenesSi603H,R, (R = EtNH, .C02Me, MeO, EtO) have been obtained through134 H. von Wartenberg, 2.anorg. Chem., 1953, 973, 257.135 G. B. Alexander, J . Amer. Chein. SOC., 1953, 75, 2887.136 R. M. Barrer, L. Hinds and E. A. White, J . , 1953, 1466.137 W. C. Schumb and R. A. Lefever, J . Amer. Chem. SOC., 1953, 75, 1513.138 C. J. Wilkins, J., 1953, 3409.139 J. Goubeau and R. Mundiel, 2. anorg. Chem., 1953, 272, 313.140 G. Fritz, ibid., 1953, 273, 275.142 S. W. Kantor, J . Amer. Chem. Soc., 1953, 75, 2712.14s J. Goubeau and H. Behr, 2. anorg. Chem., 1953, 272, 2.144 C. J. Wilkins and D. I<. Grant, J., 1953, 927.145 B. J. AyIett, H. J. Emeleus, and A. G Maddock, Research, 1953, 6, 303;.141 Idem, 2. Naturforsch., 1952, 7, b, 207, 507COATES AND GLOCKLING. 103the bromo-derivative (R = Br).The compounds are very sensitive toair and water and their preparation requires much experimental care.146The radical-exchange reactions between halides, isothiocyanates, cyanates,and phenylamino-derivatives of silicon, germanium, and phosphorus havebeen studied. 147 The alkylchlorosilanes give highly conducting solutionsin dimethylformamide, the dissociation constants being in the range 10-2 to10-4. The solutions undergo metathetical reactions. Some organo-germanium halides behave similarly. The MezSn2+ ion can be retained bycation-exchange resins, and elution with various acids has given a variety ofdime t h ylt in salts. l4The structural chemistry and reactions of the alkoxides of silicon, titanium,and zirconium have received further attention.A number of secondaryalkoxides of all three elements 149 and some alkoxyzirconium chlorides 150have been described. Zirconium alkoxides and acetyl chloride form mixedalkoxychlorides or addition compounds between the metal chloride and anester, e.g., Zr(OPri),,PriOH gave ZrC14,2Me*C02Pri.151 Theoretical aspectsof the whole series of alkoxides have been considered, including possiblestructures for the complex alkoxides in which titanium and zirconiumexhibit the co-ordination number 6. Vapour-pressure measurements ledto anomalously high entropies of vaporisation which were attributed to thepresence of complex molecules in the liquid, and a value of 18 kcal./molewas deduced for the energy of intermolecular attraction in [Zr(OEt),], and[Zr(OPri),],.The increase of entropy of vaporisation with chain lengthshown by normal alkoxides of titanium and silicon was explained in termsof “ entanglement ” of these molecules in the 1 i q ~ i d . l ~ ~ The alkoxides ofhafnium, Hf(OR), where R = Me, Et, Pri, Butt, and tert.-amyl, have alsobeen prepared and shown to resemble closely their zirconium analoguesalthough in certain cases the hafnium derivative was the more volatile.lmA preliminary communication has appeared on the preparation and pro-perties of germanium esters.154Alkyl titanates and lithium alkyls or aryls form complexes from whichthe alkyl(or ary1)titanium alkoxides maybe obtained, e g . , Ph,Ti(OR’),-, ;the stability increases with the electronegativity of R and decreases greatlyas n increases from 1 to 4.155Titanium tetrachloride and ammonia form amidochlorides at low tem-peratures, eg., Ti(NH2),C1, which decompose to TiNCl at 350°.156 Studieson complexes of Group IV elements are of particular interest in connectionwith the possibility of finding compounds in which a metal exhibits a co-ordination number of five.Titanium tetrachloride, unlike GeCl,, formsyellow complexes with a number of ethers; these are decomposed by heatto tarry products and are readily hydrolysed. Although TiC14,2Et20 isla6 H. Kautsky and H. P. Siebel, 2. anorg. Chem., 1953, 273, 113.147 H. H. Anderson, J . Amer. Chem. SOC., 1953, 75, 1576.148 K. Gingold, E. G. Rochow, D. Seyferth, A. C. Smith, and R.West, ibid., 1952,150 D. C. Bradley, F. M. Abd-el Halim, R. C. Mehrotra, and W. Wardlaw, J., 1952,152 D. C. Bradley, R. C. Mehrotra, J. D. Swanwick, and W. Wardlaw, J., 1953,2025.153 D. C. Bradley, R. C. Mehrotra, and W. Wardlaw, J., 1953, 1634.154 D. C. Bradley, L. Kay, and W. Wardlaw, Chem. and Ind., 1953, 746.155 D. F. Hermanand W. K. Nelson, .I. Amer. Chem. Soc., 1953, 75, 3877, 3882.156 G. W. A. Fowles and F. H. Pollard, J., 1953, 2588.74, 6306.4960.la9 D. C. Bradley, R. C . Mehrotra, and W. Wardlaw, J., 1952, 5020.151 Idem, J., 1952, 4609104 INORGANIC CHEMISTRY.monomeric in benzene, no molecular-weight data were obtained for the1 : 1 complexes such as that with anis01e.l~~An interesting example of solid solubility has been found ; when concen-trated hydrochloric acid is added to solutions containing ammonium ions,Ti(Iv), and Nb(v), mixed crystals of (NH,),TiCl, and (NH,),NbOCl, areformed.The latter salt, far more soluble than the former, cannot be pre-cipitated alone from aqueous s01ution.l~~Ammonium pentafluorozirconate(1v) and its monohydrate have beenobtained.Thorium hypophosphate, ThP,O,, which is useful for the separation ofthorium from rare-earth elements on account of its very low acid solubility,adsorbs both thorium and hypophosphate ions. Adsorption of thoriumions causes peptisation to clear solutions which can be dialysed and sedi-mented with an ultra-centrifuge.160Chelate complexes of Zr and Hf with a series of p-diketones,161 andthorium complexes of 8-hydroxyquinoline have been described. Someevidence is presented for the existence of [Th(~hthalate)~],- ions, and form-ation constants for the thorium complexes of a series of dibasic acids arequoted.163Germanium and its inorganic compounds have recently been reviewed.164isoPropylgermanium compounds of the types Pri3GeX (X = halogen, OH,NCS) and Pri,GeX, (X = halogen) have been prepared,165 and a series oftetra-alkoxygermanes, Ge(OR),. 166 A partial resolution of the trisoxalato-germanate(ru) ion through the quinine salt has been ~1aimed.l~'A convenient method for the preparation of dimethyltin dichloride bypassing methyl chloride through molten tin containing some copper has beenreported.168 Other salts of the dimethyltin ion 169 and hydrazine salts 170of fluoro- and bromo-stannates (SnX,),- and -stannites (SnX3)- have beendescribed.The lead oxide-bromide binary system is of interest in connection withthe formation of deposits in internal-combustion engines.An X-ray studyof this system confirms the existence of the four intermediate compoundsPhO,PbBr,, (PbO),PbBr,, (PbO),PbBr,, and (PbO) ,,PbBr, which hadearlier been detected by thermal a n a 1 ~ s i s . l ~ ~A variety of tri- and di-ethyl-lead compounds derived from mono- andpoly-basic acids have been prepared. Some metal complexes, e.g.,1 5 7 P. M. Hamilton, R. McBeth, W. Bekebrede, and H. H. Sisler, J . Avner. Chem. SOC.,1953, 75, 2881.J. Wernet, 2. anorg. Chem., 1953, 272, 279.H. M. Haendler and D. W. Robinson, J .A m e r . Chem. Soc., 1953, 75, 3846.160 T. Moeller and G. Q. Dawson, ibid., p. 3572.161 E. M. Larsen, G. Terry, and J. Leddy, ibid., p. 5107.162 T. Moeller and M. V. Ramaniah, ibid., p. 3946.163 M. Bobtelsky and I. Bar-Gadda, Bull. SOC. china., 1953, 20, 382.164 0. H. Johnson, Chem. Reviews, 1952, 51, 431.165 H. H. Anderson, J . Amer. Chem. SOC., 1953, 75, 814.166 0. H. Johnson and H. E. Fritz, ibid., p. 718.16' T. Moeller and N. C. Nielsen. ibid., p. 6106.168 E. G. Rochow and D. Seyferth, ibid., p. 2877; A. C. Smith and E. G. Rochow,169 E. G. Rochow, D. Seyferth, and A. C. Smith, ibid., p. 3099.1 7 l F. W. Lamb and L. M. Niebylski, J . Amer. Chem. SOC., 1953, 75, 511.i b i d . , p. 4103.W. Pugh, J., 1953, 1934, 2491.H. Gilman, S.M. Spatz, and M. J. Kolbezen, J . Org. Cham., 1953, 18, 1341COATES AND GLOCKLING. 105C0(NH3),C1,, react with chloroplumbic acid to give dark-coloured chloro-plumbates of the type [MA,]PbC1,,173 containing Pb(I1) and Pb(1v).Group V.-The remarkable blue compound regarded as " imine," NH,has now been obtained by passing hydrogen azide through an electric dis-charge at 0.01-0.1 mm. and condensing the effluent gas on a cold finger at-196". The blue deposit turns white at -125", giving ammonium azide.Neither ammonia nor hydrazine gave the blue compoundj but cyanic acidgave a purple deposit of similar ~r0perties.l~~The classification of oxidising agents as one- or two-electron-transferreagents, according to the nature of their reaction with hydrazine, has beenexamined in some The use of hydrazine containing 15N has shownthat for single-electron-transfer oxidation [e.g., Ce( ~ v ) , F~(III)] in acidsolution the N-N bonds are broken, while they remain intact, emerging asN,, in two-electron-transfer oxidations, e.g., V(v), and in all oxidations inalkaline s01utions.l~~A careful study of the water-ammonia system has revealed that ammon-ium oxide (NH,),O (m.p. -78.84") and hydroxide (m. p. -79.01") crystal-lise as pure compounds, and not as solid solutions in the eutectic regions.Accurate thermodynamic data were also 0btai11ed.l~~A spectrophotometric examination of the reaction between ammonia andchlorine in aqueous solution has confirmed and extended earlier work.Below pH 3 nitrogen trichloride is formed; at pH 3-5 dichloramine, andabove pH 8 monochloramine. In strongly alkaline solution chloramine ishydrolysed to h y p ~ c h l o r i t e .~ ~ ~An interesting series of salts containing the N,O,+ ion has been describedin a preliminary communication. Methods of formation include the actionof nitric oxide on nitrosyl aluminium chloride (NO+AlCl,-) in liquid sulphurdioxide or on nitrosylsulphuric acid, giving the so-called " blue acid,"N,O,+ HSO,;, and reduction of nitrosylsulphuric acid with sulphur dioxide,methanol, or formic acid.179Reactions involving dinitrogen tetroxide have received further study.Unstable addition compounds of the type N,0,,2B are formed with manytertiary arnines,lg0 while calcium and zinc oxides, and sodium peroxide andcarbonate give the metal nitrates.lsl Uranium and dinitrogen tetroxidecontaining an amine nitrate react with evolution of nitric oxide and formationof a trinitratouranyl complex, e.g., Et,NH[UO,(NO,)J.The reaction ratesincrease with dielectric constant in the absence of amine nitrate (e.g., additionof Et,N-NO), which suggests that reaction involves [NO+][NO,-] ion pairsfollowed by progressive oxidation of Unf ions : U __t Un+ -% U02+ %U022+.182 The conflicting data on the dipole moment of N,O, have beennNO+173 M. Mori, Bull. Chem. SOC. Japan, 1951, 24, 285 (Chem. Abs., 1953, 47, 3739).174 F. 0. Rice and M. Freamo, J . Amer. Chem. Soc., 1953, '75, 548; see also idern,175 W. C. E. Higginson, D. Sutton, and P. Wright, J ., 1953, 1380.176 W. C. E. Higginson and D. Sutton, J.. 1953, 1402.177 D. L. Hildenbrand and W. F. Giauque, J . Amer. Chem. Soc., 1953, 75, 2811.R. E. Corbett, W. S. Metcalf, and F. G. Soper, J . , 1953, 1927.17s F. Seel, B. Ficke, L. Riehl, and E. Volkl, 2. Naturforsch., 1953, 8, b, 607.180 D. A. Davenport, H. J. Burkhardt, and H. H. Sisler, J . Amer. Chem. Soc., 1953,181 C. C. Addison and J. Lewis, J . , 1953, 1319, 1874.182 C. C. Addison and N. Hodge, Nature, 1953, 171, 569.ibid., 1951, 73, 5529.75, 4175106 INORGANIC CHEMISTRY.reinterpreted by assuming that pN,O, is zero and that pNO, varies withtemperature. l*3The complicated thermal decomposition of calcium nitrite and hypo-nitrite has been studied.ls4When the vapour from white phosphorus is cooled from 600" on to a coldfinger at -196" only white phosphorus condenses.Cooling from lOOO",however, produces a dark brown deposit which changes irreversibly and a ta measurable rate between -100" and -50" into a mixture of white (80%)and red (20%) phosphorus. Brown phosphorus, assumed to be P,, isinsoluble in boiling propane or ethylene and in carbon disulphide at - 103" ;it is not appreciably paramagnetic. The formation of brown phosphorus ona cold finger held above red phosphorus at 350-360" is significant andsupports the view that P, molecules evaporate from heated red phosphorusand subsequently dimerise. lS5Greatly improved methods for the preparation of the three methyl-phosphines are described, involving successive methylation of phosphinewith methyl chloride in liquid ammonia containing the requisite quantityof sodium of barium.lS6Hypophosphoric acid is fully methylated by diazomethane ; the product,(MeO) 4P20,, is a monomeric, colourless, viscous 1iq~id.l~' Hydrolysis ofphosphorus tribromide by ice-cold aqueous bicarbonate gives the sodiumsalt of a new oxyacid of phosphorus, sodium diphosphite Na3HP,0,112H,0.Diphosphorous acid and its salts are oxidised to hypophosphoric acid (H,P,O,)by iodine and bicarbonate, and to pyrophosphoric acid by chlorine orbromine.lss There is some evidence] magneto-optic and cryoscopic, thatphosphorous acid is present largely as dimer, H6P20,, in non-aqueous solventsand concentrated aqueous solutions.lS9 Various esters of triphosphoricacid have been described.lgOA review of the metaphosphates and their behaviour on hydrolysis hasappeared.lgl Lead metaphosphate [Pb(PO,),].has been prepared byheating Pb(H,PO,), at 400°, and X-ray analysis indicates a long-chainpolymeric anion. Stirring a suspension with aqueous sodium sulphide givesa solution of sodium metaphosphate which, at 2% concentration, is about asviscous as glycerol, and gives a deep orange-red colour with silver salts.lg2Tertiary aromatic phosphine oxides add potassium to give " phosphyls,"ion radicals analogous to the ketylsPh,PO + K __t Ph,l?-O-K+These phosphyls are blue and paramagnetic in solution ; they can add anotherelectron, giving deep violet solutions containing Ph3P--O-)'K22+. Themagnetic properties of the latter are not reported.lS3Bond-energy data, mainly from heats of hydrolysis, suggest that the183 C.C. Addison and J. Lewis, J . , 1953, 1869.184 T. M. Oza and V. T. Oza, J., 1953, 907, 909.1135 F. 0. Rice, R. Potocki, and K. Gosselin, J . Auner. Chem. Soc., 1953, 75, 2003.186 R. I. Wagner and A. B. Burg, ibid., p. 3869.187 M. Baudler, 2. Naturforsch., 1953, 8, b , 326.188 B. Blaser, Bey., 1953, 86, 563.190 R. Ratz and L. Engelbrecht, 2. anorg. Chem., 1953, 272, 326; R. Ratz and E.392 K. R. Andress and K. Fischer, ibid., 1953, 273, 193.193 F. Hein, H. Plust, and H. Pohlemann, ibid., 1953, 272. 25,D. Voigt, Bull. Soc. chinz., 1953, 20, 517.Thilo, ibid., p- 333. 191 E. Thilo, G. Schulz, and E. M. Wichmann, ibid., p.182COATES AND GLOCKLING. 107P=O bond in the phosphorus oxyhalides resembles a double rather thana single (P+-0-) bond.lg4The low conductance of phosphorus pentachloride in phosphorus oxy-chloride, dioxan, ether, and nitrobenzene indicates that it is largely in acovalent form. In acetonitrile the conductance is much greater, andtransport measurements indicate the ionisation 2PC1, PCl,+ + PCl,-.lS5Conductometric titrations in POCl, solution have provided evidence forthe compounds : PCl,+SnCl,-, ( PCl,+),SnC162-, PCl,=TiCl,, PCl,+BCl,-,PC14+TeC1,- , and (PC1,+),TeC1,2-.1s6Hydrazine and related salts of antimony and bismuth halides lD7 and a1 : 1 addition compound of SbF, and dioxan lS8 have been obtained.Vanadium occurs in certain blood pigments and, in connection with these,a number of vanadium complexes have been investigated, mainly withethylenebissalicylaldimines, and their reduction-oxidation properties ex-amined.Some of these compounds behave in a similar manner to hmm-vanadium.lS9 The system Na,O-V,O,-H,O has been examined again, anda number of errors corrected.200Polarographic and spectrophotometric evidence for the existence of + 3and +4 oxidation states of niobium and tantalum in solution has beenobtained.201 A re-examination of the reaction between niobium penta-chloride and ammonia has led to the suggestion that impure niobium nitrideis produced through an intermediate NbC1,(NH2)2.202 Iodic and periodicacids form heteropoly-acids with niobium and tantalum.203Group V1.-The triple-point temperature (4.49" & 0-02') of tritium oxide,T,O, has been measured with use of only 0.15 C.C.(cf. D,O, 3-81').204The dehydration of several salt hydrates has been interpreted on thebasis of the formation of hydroxy-bridges, similar to those present in thep-diolcobalt ammines.205Two new allotropes of sulphur have been prepared.206 At 500-700"and between 0.1 and 1 mm. pressure, sulphur vapour consists mainly ofS, molecules ; if this vapour is allowed to impinge on a cold finger at - 196"a purple solid condenses. This has been named purple sulphur and itsparamagnetism 207 supports the suggestion that it consists of S, molecules.Purple sulphur is insoluble at -80" in propane, dimethyl ether, and toluene ;it is non-conducting and not volatile without decomposition.Even at-80" it slowly changes to yellow sulphur; the change is rapid at roomtemperature and a mixture of crystalline (40%) and amorphous (60%)sulphur is formed. Condensation at - 196" of the vapour from solid sulphurgives yellow rhombic sulphur, but condensation of vapour from liquid sulphurgives another allotrope, green sulphur. This probably consists mainly oflQ4 T. Charnley and H. A. Skinner, J., 1953, 450. lQ5 D. S. Payne, J., 1953, 1052.196 W. L. Groeneveld and A. P. Zuur, Rec. Trav. chim., 1953, 72, 617.lg7 W. Pugh, J., 1953, 1934, 3445.Ig8 H. M. Haendler, R. H. Glazier, and D. W. Breck, J . Amer. Chem. SOC., 1953, 75,lg9 H. J. Bielig and E. Bayer, Annalen, 1953, 580, 135.zoo H. Menzel and G.Miiller, 2. anorg. Chem.. 1953, 272, 81.201 R. E. Elson, J . Amer. Chem. Soc., 1953, 75, 4193.202 G. W. A. Fowles and F. H. Pollard, J., 1952, 4938.203 D. Sen and P. RAY, J . Indian Chem. SOC., 1953, 30, 250.204 W. M. Jones, J . Amer. Chem. SOC., 1952, 74. 6065.205 W. S. Castor and F. Basolo. ibid., 1953, 75, 4804, 4807.208 F. 0. Rice and C . Sparrow, ibid., p. 848; F. 0. Rice and J. Ditter, ibid., p. 6066.207 T. Freund, S. Adler, and C. Sparrow, J . Chem. Phys., 1953, 21, 180.3845108 INORGANIC CHEMISTRY.S, chains instead of S, rings; it reverts to yellow sulphur slowly at -100"and in a few seconds at room temperature.In a discussion on the allotropy of sulphur the strongly catalytic actionof sulphide ions and bases in accelerating the interconversion of allotropes isascribed to the opening of eight- or higher-membered rings with the form-ation, not of free radicals, but of normally constituted intermediates,20s e.g.,S' + (SJrhg 4 s--s---s-s-It is weakly para-magnetic.RaN + (S,)fins R,N+-S---S-S-The unbranched structure, OSSO, is preferred to S(S0,) for the dimerS,O, present in gaseous sulphur monoxide.209There have been substantial developments in the chemistry of thesulphur nitrides. The preparation of sulphurimide (S,NH) from S,Cl,and ammonia has been improved, and a 15% yield can now be obtained.Crystallised from methanol, it is colourless, m. p. 112.5", and it is monomericin benzene. With mercuric acetate an insoluble derivative Hg(NS,), isformed, but formaldehyde and alkali give colourless monomeric (in benzene)S,N*CH,*OH .210The sulphur hydronitride (HNS),, prepared by an improved methodfrom N,S,, reacts with mercuric acetate in pyridine with the formation ofa bright red colour followed by the deposition, in 97% yield, of green crystalsof Hg,(NS),.Excess of mercuric acetate, however, gives the yellow com-pound Hg(NS), in lower yield. A new oxysulphide of nitrogen, formulatedas (NS),SO, results from the reaction between Hg,(NS), and either thionylchloride ,or ethyl chlorosulphinate,Hg,(NS)* + 4sOcl2 = 4(NS),SO + 3HgC1, + Hg2Cl,Hg,(NS), + EtO*SOCl __t NS.SO*OEt __t (NS),SO + (EtO),SO(not isolated)The compound (NS),SO is an orange, mobile liquid, monomeric in benzene,and slowly decomposes even at 0" with the formation of N,S,.Alkalinehydrolysis gives ammonia :(NS),SO + 40H- + H,O = S,O,' + SO," + 2NH,The reaction between Hg,(NS), and sulphuryl chloride gives a dark blue,insoluble, probably polymeric, substance Hg,C1,(NS),.211A yellow crystalline substance, S3N202, m. p. 100-7", has been obtainedfrom ammonia and excess of thionyl chloride, and probably has the structure(VII, a, b, c). Monomeric in nitrobenzene, it is soluble in various organic208 H. Krebs and E. F. Weber, 2. anorg. Chem., 1953, 2'78, 288.210 A. Meuwsen and F. Schlossnagel, ibid., 1963, a71, 226211 A. Meuwsen and M. Losel, ibid., p. 217, 221.P. W. Schenk, ibid., 1952, 270, 301COATES AND GLOCKLING. 109solvents and can be sublimed.by alkali, giving trithionate :S3N20z f 4H20 = (NH4)zS306It is also formed, doubtless through S4N,)C1, when sulphur dioxide is bubbledinto a boiling solution of S,N, in thionyl chloride (S4N4 + 2S0,-Thiotrithiazyl chloride (S4N,Cl) liberates iodine from hydriodic acid, theThe structure (VIII, a, b, c)I t is hydrolysed by damp air, and rapidlySS3N2O2) .z12mean oxidation level of the sulphur being + 2 6+(VI I Ia)++ +-(VI I I b ) (VI I Ic)is suggested for the S4N,+ ion also by reactions with piperidine and withdilute ammonia vapour, the latter giving S,N,*NH3)C1.213The phase diagram for sulphamide-ammonia indicates formation ofS0,(NH,),,2NH3 and S0,(NH,),,3NH3.No 1 : 1 compound is formed.214The reaction between ammonia and sulphur trioxide in nitromethanesolution (in which SO, is monomeric) gives a mixture of ammonium tri-sulphate (NH4),S,0,,, and polymeric sulphimide (NHSO,),.The silversalt of the latter, with methyl iodide, gives not only the previously known(MeN-SO,),, but also (MeN*S0,)4.z15A further study of the reaction between sulphuryl chloride and ammoniasuggests that the ion NS0,- is an intermediate product. In the presenceof thionyl chloride, sulphanuric chloride (NSOCI),, m. p. 144-145", isobt aineda216Pyrosulphurylchlorofluoride, S205ClF, b. p. 100.1", is formed from S205C12 and silverfluoride, no S20,F2 being produced.217 The oxyfluoride S,O,F,, b. p. 120'(decomp.), is obtained as a heavy lower layer when BF, reacts with liquidSO, and concentrated sulphuric acid is added.Other methods are the thermaldecomposition of the compound I<BF,,4SO, and the reaction between KBF,and liquid SO, at - 70". The structure FS0,~O*S02*O*S0,F is suggested.218The reaction between sulphur trioxide and potassium fluoride has beenfurther examined. At room temperature a liquid is formed which depositscrystals of potassium fluorodisulphate, KS,O,F, on standing over concen-trated sulphuric acid in V ~ G U O . On heating, the salt loses a mole of sulphurtrioxide : 219Some new oxyhalides of sulphur have been prepared.K+[O,S.O*SO,Fj- --+ KS03F + SO,A Raman spectrum and phase-rule study of the sulphur trioxide-methane-sulphonic acid system has revealed the existence of a mixed anhydrideMe*SO,*O-SO,H ,2Me*S03H.220212 RI. Goehring and J.Heinke, 2. aNorg. Chem., 1953, 273, 297.213 M. Goehring and D. Schuster, ibid., 1953, 271, 281.214 H. H. Sisler and D. M. Rosenblum. .J. Amer. Chem. Soc., 1952, 74, 6130.215 R. Appel and M. Goehring, 2. apaorg. Chern., 1953, 271, 171.216 M. Goehring, J. Heinbe, H. Mak, and G. Roos, ibid., 1933, 273, 200.217 A. Engelbrecht, ibid., p. 269.2*8 H. A. Lehmann and L. Kolditz, ibid., 1953, 272, 73.219 Idem, ibid., p. 69. 220 I. Sandeman, J., 1953, 1135110 INORGANIC CHEMISTRY.Further work on sulphuric acid as an ionising solvent confirms that thefreezing point is maximum (10.36-10.37") and the electrical conductivityminimum (0.01033 ohm-l cm.-l at 25") at the composition H,S0,.221 Theconductivity, which is large for a pure liquid, is attributed to extensiveself-dissociation giving the ions H,O+, HS20,-, H,SO,+ , and HS0,- .222Transport-number measurements show that the last two ions have abnorm-ally high mobilities, of the order of 50-100 times those of other ions, anda chain mechanism involving proton transfer is suggested.223 The extent ofsolvation is K+ < Ag+ < Na' < Li+ < Ba++ < Sr++ , this order being confirmedby studies on the density and viscosity of solutions in sulphuric a ~ i d .2 ~ ~Conductivity measurements show that not only are the hydrogen sulphatesof the above ions strong electrolytes but so also are acetic, benzoic, andnitric acids, acetone, methanol, ethanol, triphenylcarbinol, rt-propylamine,aniline, o-phenylenediamine, hexamethylenetetramine, and dinitrogen tetr-oxide.Disulphuric acid, dichloroacetic acid, and p-nitrotoluene are weakelectrolytes, while sulphuryl chloride and trichloroacetic acid do not con-duct.225 The autoprotolysis of sulphuric acid has also been examined.2Z6By using H235S in the reaction,4so2 + 2H2S + 6NaOH = 3Na2S203 + 5H20it was established that all the central sulphur in the thiosulphate ion (Ex:)=originates from inactive SO,, while the exterior sulphur comes partly fromthe H2S and partly from the SO,.227A careful investigation of the sulphides of sodium, including preparationsfrom the elements in alcohol, toluene, and liquid ammonia, has shown thatNa,S,, Na,S,, and Na,S, may be obtained. A trisulphide, Na2S3, wasprepared in these ways but X-ray analysis has shown that it was not a singlesubstance, in contrast to the other polysulphides.The disulphide existsin two forms, and the pentasulphide is the highest stable polysulphide.228Numerous double sulphides, selenides, and tellurides, e.g., CuAlS,,CuGaSe,, and AgInTe,, have been made and generally found to crystallisewith the chalcopyrites (CuFeS,) stru~ture.2~~Selenium dithiocyanate, Se(NCS),, crystallises under suitable conditionsfrom an acidic solution of selenious acid to which a thiocyanate has beenadded. It is fairly stable at 5" if protected from moisture but suddenlydecomposes at 83-85' ; in dioxan or acetophenone it is monomeric.230Selenium tetrafluoride combines with mercury and with sulphur trioxide,forming HgSeF, and SeF,,SO,F,Tellurium dichloride has been prepared in good yield from CF,CI, and221 J. E.Kunzler and W. F. Giauque, J . Amer. Chem. Soc., 1952, 74, SO-1.222 K. J. Gillespie and s. Wasif, J . , 1953, 201.223 Idem, ibid., p. 209.225 Idem, ibid., p. 221.227 M. €3. Neyman, E. S. Torsueva, A. I. Fedoseeva, and P. S. Shantarovich, DoFzZady228 F. Feher and H. J. Berthold, 2. anorg. Chem., 1953, 273, 144.229 H. Hahn, G. Frank, W. Klingler, A. D. Meyer, and G. Storger, ibid., 1953, 271, 163.230 S. M. Ohlberg and I?. A. van der Meulen, J . Amer. Clzem. SOC., 1953, 75, 997.231 R. D. Peacock, J., 1953, 3617.224 Idem, ibid., p. 216.228 Idem, ibid., p. 964.Akad. Nauk S.S.S.R., 1952, 86, 317COATES AND GLOCKLING. 111molten tellurium ; it disproportionates rapidly in solution, into Te + TeC14.232Tellurium tetrafluoride forms an insoluble 1 : 1 co-ordination compoundwith pyridine ; the salt (pyH),TeF, was also prepared.233 The decafluoride,Te,F,,, is formed in yields up to 20% by the direct fluorination of telluriummixed with calcium fluoride.It is remarkably volatile (b. p. 54"; M ,Phase equilibrium data are given for the system Cr,(S0,)3-H,S04-H,0at 25" ; chromium does not form solid acid ~ u l p h a t e s . ~ ~ ~Several more addition compounds between chromium trioxide andpyridine bases have been prepared ; some, e g . , CrO,,a-picoline, are stableat room temperature. Chromium trioxide is monomeric in pyridine andboth cc- and p - p i ~ o l i n e . ~ ~ ~The oxidation of oxalic acid by potassium dichromate is well known to bean unsuitable reaction for volumetric purposes, and E.A. Werner 237 showedthat potassium dioxalatodiaquochromate(rII), IC[Cr(C,O,),(H,O),], wasfrequently formed in the reaction. The kinetics of the formation of thissalt from [Cr(H,0),l3+ ions and oxalate ions have now been studied polaro-graphically; the rate is limited by two consecutive slow reactions.238 Asolution of the complex contains, at equilibrium, much more of the cis- thanof the trans-isomer. The latter, however, crystallises when a solution isconcentrated sZowZy, since its solubility is so much less than that of the cis-isomer. The kinetics of the cis-tvans-isomerisation in this system havebeen studied spectrophotometrically at various temperatures, giving theheat, entropy, and free energy of isomerisati~n.~~~Improved preparations of chromium(m) ammines of the types [Cr en3]X3,[Cr en,Cl,]X, and [Cr,(OH),en,]X, have been described.240Some cis-diazidochromium(II1) complexes of the type [Cr en2(N3),]+ havebeen obtained from [Cr en3]C13 and NaN, in aqueous solution.241Thermal decomposition of tetraphenylchromium halides gives a mixtureof chromium carbide with reduced halides of chromium; the volatile pro-ducts contain much di~henyl.,,~The compounds Mo3Ge,, M02Ge3, a-MoGe,, and F-MoGe, have beenprepared, as well as the previously known M o , G ~ ., ~ ~Experiments using the 66-hour isotope sgMo have shown that the charge-transfer reaction between the Mo(CN),3- and Mo(CN),4- ions in aqueoussolution is extremely rapid.244The alkali fluorides interact with tungsten(v1) oxide in much the sameway as with molybdenum(vI)*oxide, and salts M3W03F3 and M3W04F havebeen prepared.245445) .234232 E.E. Aynsley, J., 1953, 3016.233 E. E. Aynsley and G. Hetherington, J., 1953, 2803.234 W. D. English and J. W. Dale, J., 1963, 2498.235 D. Taylor, J., 1953, 2502.236 H. H. Sisler, W. C. L. Ming, E. Metter, and 1'. R. Hurley, J. dnaer. Chenz. SOC.,238 R. E. Hamm and R. E. Davis, J . Anzer. Chem. SOC., 1953, 75, 3083.239 R. E. Hamm, ibid., p. 609.240 M. Linhard and M. Weigel, 2. aizorg. Chem., 1952, 271, 115.241 Idem, ibid., 1953, 271, 131.2J2 F. Heiii and H. Pauling, i t i d . , 1953, 273, 209.243 A. W. Searcy and R. J. Peavler, J . Amer. Claem.SOC., 1953, 75, 5657.244 R. L. Wolfgang, ibid., 1952, 74, 6144.245 0. Schmitz-Dumont, I. Bruns, and I. Heckinann, 2. morg. Clzem., 1953, 271, 347.1953, 7'5, 446. 237 E. A. Werner, J., 1888, 53, 602112 INORGANIC CHEMISTRY.Cryoscopic measurements in ice-sodium nitrate eutectic mixtures indi-cate that the main ion present in sodium peroxotungstate solutions isUranium and the Trans-uranic Elements.-Examination of the uranium-hydrogen system has been extended to a considerably wider range ofpressures and temperatures. The equation, log,, Pcm. = 5.78 - 1730/T, forthe dissociation pressure of UH, was obtained by observations between 500and 4900 cm. and 357-650", on compositions from UH,.,, to UH,.,. Thelimiting composition is UH,.,-,O.~~'The atmospheric oxidation of uranium dioxide at 120" has been followedby X-ray diff racti0n.2~~ Several investigations on mixed oxides containinguranium are reported.Uranium dioxide and magnesium oxide form solidsolutions only (no compounds) between 300" and 2350". The resultingfluorite structure with anion vacancies contains only a few moles yo of mag-nesia and has a great affinity for oxygen. The solid solubility of magnesiaincreases considerably as oxygen is taken up to near the limiting compositionThe relation between lattice constant and composition has been measuredfor the mixed oxides U,08-La20,, where La may be any of the lanthanonsLa, Pr, Nd, Sm, Yb, or Sc. The colours of these mixed oxides are brightand various, and in some cases there is opportunity for a random distributionof ions of different charge, e.g., Pr3+ and Pr4+.250 Cerium-uranium blue,CeUO,, has been prepared by ignition of the mixed hydrated oxidesprecipitated from Ce4+-U4+ salt solutions.The oxide has a fluorite lattice,and can be oxidised to CeUO,.,, by heating in oxygen. The electricalconductivity of the oxide is interesting in connection with the possibilityof electron exchange : 251 Ce4+ + U4+ + Ce3+ + U5+. The magneticsusceptibilities of UO,-ThO, solid solutions confirm the 6d2 configurationfor U ( IV) .2 52The inhibition by carefully dried potassium fluoride of the reactionbetween uranium hexafluoride and glass has greatly facilitated the measure-ment of a number of properties of this very reactive substance.Nickelresists attack even at 100" ; mercury is rapidly corroded at room temperature,but the reaction with dry Apiezon grease is so slow that greased taps maybeThe chlorination of U,O, with gaseous hydrogen chloride, previouslyattempted without success at lower temperatures, goes practically to com-pletion in three hours at 1200" ; the product is' U02C12.254Factors affecting the efficiency of the reduction or uranyl chloride toU(IV) chloride have been examined.255In attempts to prepare volatile compounds of uranium, complexes withthirteen 1 : 3-dicarbonyl compounds were prepared (some containing CF,246 K. F. Johr and 1LI. Blanke, 2. anovg. Chem., 1953, 272, 45.247 T. R. P. Gibb, J. J. McSharry, and H. W. Kruschwitz, J . Anzer. Chem.SOL, 1952,249 J. S. Anderson and K. D. B. Johnson, J., 1953, 1731.250 F. Hund and U. Peetz, 2. anorg. Chem., 1952, 271, 6.251 W. Riidorff and G. Valet, ibid., 1953, 271, 257.252 T. K. Dawson and M. W. Lister, J . , 1952, 5041.253 D. R. Llewellyn, J., 1953, 28.254 B. I. BoiiC and 0. Gal, 2. anorg. Chem., 1953, 273, 84.255 H. K. El-Shamy and S. El-Din Zayan, J., 1953, 384.[w203(0)2) 4, aq'l -'246uo,,~g0.24974, 6203. 24* P. Perio, Bull. Soc. chinz., 1953, 20, 256COATES AND GLOCKLING. 113groups). None of these, however, was as volatile as the borohydride ormet hylborohydride. 256X-Ray and chemical evidence suggests that f orbitals contribute tobonding in uranyl and plutonyl ions. Bonding byforbitals is only significantat small internuclear distances.257Further work on the disproportionation of pIutonium(1v) in acid solutionhas shown that a-particles from the plutonium seriously interfere withestablishment of equilibrium,2583Pu4+ + 6H20 e- 2Pu3+ + Pu02++ + 4H30+Suitable corrections have now been applied.The equilibrium constantdepends on the fourth power of the hydrogen-ion concentration; thissupports the existence of plutonyl ions P U O , + + . ~ ~ ~ The same is true for theequilibriumand thermodynamic data for both neptunium ions have been obtained.260The NpO,+ ion forms the complexes NpO,(C,O,)- and Np02(C20,),3-, whoseassociation constants have been measured.261 The neptunium compoundsNpC,, NpSi,, NpN, and Np,P, have been prepared, and their crystal formsstudied.262Group VI1.-Little work has been reported on inorganic fluorides ; thecompounds KMgF,, K,MgF,, and AgZnF, have been identified in the systemsKF-MgF, and A~F-ZIIF,,~~~ and a remarkable fluoride, NaCaCdYF,, whichhas the calcium fluoride structure.The metal ions, which are all about thesame size, are randomly distributed among the Ca++ positions.26* Con-venient preparative methods for the fluorinating agents, silver and antimonyfl~orides,2~~ and solubility determinations on a number of metal fluorides inBrF,,266 are reported.Valuable manipulative techniques involved in the preparation of sodiumfluoroacetate, labelled with 14C in the methylene group, have been de-~ e l o p e d . ~ ~ ' Direct fluorination methods under mild conditions by diffusionof reactants through nitrogen result in a very diffuse luminous flame in whichan average temperature as low as 48" can be maintained.This techniquehas been applied to the fluorination of carbon disulphide and has yieldedthe fully saturated derivative SF,*CF2*SF5 as well as SF,-CF,*SF,, CF,-SF,,CF,*SF,, CSF,, SF,, and S2F,,.268 A more satisfactory method is describedfor preparing the dangerously explosive compound trifluoroacetyl hypo-fluorite, CF,*CO,F (b. p. -21.5" & 1") by direct fluorination of CF3*C02H.2692 5 6 H. I. Schlesinger, H. C. Brown, J. J. Katz, S. Archer, and R. A. Lad, J . Anzev.Chewz. Soc., 1953, 75, 2446. 2 5 7 R. E. Connick and 2. 2. Huggs, ibid., 1952, 74, 6012.258 R. E. Connick and W. H. McVey, ibid., 1953, 75, 474.259 S.W. Rabindeau, ibid., p. 798.260 L. B. Magnusson and J. R. Huizenga, ibid., p. 2242.2 6 1 D. M. Gruen and J. J. Katz, ibid., p. 3772.262 I. Sheft and S. Fried, ibid., p. 1236.263 R. C. DeVries and R. Roy, ibid., p. 2479.264 F. Hund and K. Lieck, 2. anorg. Chenz., 1952, 271, 17.265 F. A. Anderson, B. Bak, and A. Hillebert, Acta Chem. Scand., 1953, 7, 236.266 I. Sheft, H. H. Hyman, and J. J. Katz, J . Amer. Chem. Soc., 1953, '95, 5221.267 €3. C. Saunders and T. S. Worthy, J., 1053, 1929.268 E. A. Tyczkowski and L. A. Bigelow, J . Amer. Chem. SOC., 1953, '95, 3523.269 G. H. Cady and K. B. Kellogg, ibid., p. 2501.Np4+ + Fe3+ + 6H,O Np02+ + Fe++ + 4H,O114 INORGANIC CHEMISTRY.Earlier work on the formation of cyanogen fluoride by the reaction AgF +ICN = AgI + FCN has been disproved, though some 3% of a producthaving mass 45 was found.270A convenient laboratory cell for electrolyses in anhydrous hydrogenfluoride has been used with dimethyl sulphide, which gave CF,*SF, (20%)and (CF,)2SF, (2%) in addition to much CF, and SF,.Carbon disulphideformed the compounds CF,*SF,, CF,(SF,),, CF,(SF,),, and free sulphur.Attempts to fluorinate the corresponding selenium compounds were un-su~cessful.~~1An improved method for the preparation of fluorocarbon iodides fromsilver salts of perfluoro-acids and iodine avoids the use of liquid solventsand d i l ~ e n t s . ~ ~ ~Studies on the reactions between trifluoroiodomethane and variouselements have been extended to phosphorus 273 and arsenic.274 The reactionsare believed to involve radical intermediates produced by homolytic fission,CF31 ___t CF,.+ I.With white phosphorus the compounds (CF,),P, (CF,),PI, CF,*PI,, P,I,,and PI, are formed (at 200-220"). Tristrifluoromethylphosphine, P(CF,),,b. p. 17.3", is spontaneously inflammable, but differs from its methyl analoguein not reacting with sulphur or carbon disulphide, nor does it co-ordinate tosilver or mercuric iodides. The monoiodo-compound (CF,),PT is particularlyinteresting since (CF,),P*P(CF,),, b. p. 84", is formed on reaction withmercury, and methyl analogues of neither of these are known.Trifluoromethylphosphines are readily hydrolysed by alkali, givingfluoroform, whereas alkyl- and aryl-phosphorus bonds are resistant tohydrolysis.Arsenic in a similar reaction with CF,I at 220" gives mainly tristrifluoro-methylarsine, (CF,),As, b.p 33", with small amounts of (CF,),AsT andCF,-AsI,. Tristrifluoromethylarsine, like (CF,),P, does not react withmercuric chloride, sulphur, or methyl iodide (in the dark). With gaseousmethyl iodide, ultra-violet irradiation causes an unusual exchange reactionto take place, with the formation of CH,As(CF,),, b. p. 52". The latter, too,does not co-ordinate to mercuric chloride. The halides (CF,),AsX andCF,*AsX,, best obtained from (CF,),As, are reduced by zinc and acid to thearsines (CF,),AsH and CF,-AsH,. Other compounds prepared include thefully fluorinated cacodyl, (CF,),As*As(CF,),. Like the sulphur and phos-phorus compounds, trifluoromethylarsines are sensitive to alkaline hydrolysis,with formation mainly of fluoroform.Bistrifluoromethylarsinous acid,(CF,),As*OH, obtained as the silver salt from (CF,),AsI and moist Ag,O,is very unstable, but the corresponding arsinic acid, (CF3),As0,H (hexa-fluorocacodylic acid), from (CF,),AsI and aqueous hydrogen peroxide, isstable. The electronic effect of the fluorine is well illustrated by the strengthof (CF,),AsO,H, comparable to that of hydrochloric acid (cf. cacodylic acid,270 H. J. Callomon, H. W. Thompson, F. A. Andersen, and B. Rak, J . , 1953, 3709.271 A. F. Clifford, H. K. El-Shamy, H. J. EmelCus, and R. N. Haszeldine, J., 1953,273 F. h i . Bennett, H. J. EmelCus, and R. N. Haszeldine, J . , 1953, 1565.274 G.R. -4. Brandt, H. J. EmelCus, and R. N. Haszeldine, J., 1952, 2552; H. J.Emel&s, R. N. Haszeldine, and E. G. Walaschewski, J., 1953, 1552; E. G. Wa!aschewslti,B e y . , 1953, 06, 272.2372. 2 5 2 G. H. Crawford and J. H. Simons, J . Anzer. Chem. SOC., 1953, 7'5, 5737COATES AND GLOCKLING. 115pK = 6.4); it would appear to be dibasic but in alkaline solution decom-position to fluoroform occurs.Iodine pentoxide dissolves in boiling iodine pent afluoride giving a colour-less solution which deposits iodine oxytrifluoride, IOF,, on cooling. Thelatter disproportionates on heating, ZOF, + I0,F + IF,, .giving a newoxyfluoride, iodyl fluoride, as a white solid, stable in dry air, but easilyhydrolysed to hydrofluoric and iodic acids. Solution in icdine pentafluorideregenerates IOF,.With the oxides P,O,,, V,O,, CrO,, and W03, iodinepentoxide gives POF,, VOF,, CrO,F,, and WO,,SIF,. Iodine pentafluorideabsorbs nitrogen dioxide giving a cream-coloured compound NO,,IF,, whichsublimes on gentle heating ; with potassium nitrate the iodohexafluorideKIF, results, and mercury gives the remarkable substance Hg(IF,),,apparently insoluble in water.275Anhydrous perchloric acid can be obtained from the 720/, acid and oleumby low-t emperature distillat ion. 76 Thermal decomposition of potassiumperchlorate is complicated : some chlorine as well as oxygen is producedin vacuo, but only oxygen when an inert gas is present. Some chlorate isalso f0rmed.2~7When a mixture of nitrogen, oxygen, and bromine is subjected to a low-pressure discharge a white solid is produced which is said to have the com-position (NO,),BrO, and to be volatile a t -40".The same substance isformed from bromine dioxide and nitrogen dioxide. Chlorine and iodinereact differently with nitrogen and oxygen, giving NOClO, and I,O,,respectively.278From the free energies of formation of complexes of halogens witharomatic compounds and of trihalide ions, the electron-acceptor orderICl > BrCl > IBr > I, > Br, > C1, is deduced.279 The solubility of iodinein aqueous sulphuric acid is a minimum at the composition H,0+HS04-.280It is well known that manganese heptoxide is formed from potassiumpermanganate and concentrated sulphuric acid, but the properties of thisdangerous compound have been studied only recently.I t has m. p. 5.9"and decomposes rapidly above 55". It is a non-conductor, having a di-electric constant of 3.28, and its shock sensitivity is similar to that of mercuryThe reduction of potassium permanganate is necessarilycomplex, and it is pointed out that manganese ions of valency intermediatebetween MnO,, and Mn0,- must be involved, thoGgh very little isknown about them. The reactions of various organic compounds withalkaline permanganate, insoluble barium manganate being used to removeMnO," ions as formed, have been studied and compared with manganicoxidations using manganese(rI1) pyrophcsphate.2s2A new apparatus for reduction by potassium in liquid ammonia withexclusion of air has been applied to the reduction of K,Mn(CN),.The paleyellow product, which is very sensitive to oxygen, has the composition275 E. E. Aynsley, R. Nichols, and P. L. Robinson, J., 1953, 633.2 7 6 G. F. Smith, J . Anzev. Chew. SOC., 1953, 75, 184.2 7 7 L. L. Bircumshaw and T. R. Phillips, J . , 1953, 703.278 A. Pflugmacher, 2. anorg. Chein., 1953, 273, 41.279 R. L. Scott, J . Amer. Chem. SOC., 1953, 75, 1550.280 J. G. Bower and R. L. Scott, ibid., p. 3583.281 0. Glemser and H. Schroder, 2. anoug. Chew., 1953, 271, 293.*E2 A. Y . Drummond and W. A. Waters, J . , 1953, 435116 INORGANIC. CHEMISTRY.K5Mn(CN),,K,Mn(CN),,2NH, and appears to contain both Mn(1) andMn(o) ; it is pararnagneti~.,~~Lithium rhenide (Li' Re-) has been prepared as a crystalline hydrate.284Electrolytic reduction of per-rhenates in concentrated sulphuric acidprovides some evidence for an unstable Re(v1) whilst reductionof per-rhenic acid with hydrogen iodide gave salts of Re(1v) and Re(v), e.g.,(NH4),Re16.286 The complex, cis-Re(py,Cl,), has been obtained frompyridine and (NH,),ReCl,, and the corresponding trans-isomer by the actionof hydrochloric acid an Re(py,C1,).287 Rhenium oxide and catechol oroxalic or gallic acid form complex acids,288 e.g., H[ (OH),Re(C,O,)H,O].Vapour-pressure and other thermal data have been obtained for two newsilicides of rhenium, Re,Si and ReSi, prepared by direct synthesis.Bothare thermodynamically unstable at 25" relative to ReSi,.zs9Group VII1.-The effect of pH on the rate of oxidation of ferrous hydr-oxide has an important bearing on the alkaline corrosion of iron. At a lowpH, y-Fe,O,,H,O is obtained ; in more alkaline solutions a-Fe,O,,H,O isformed when the oxidation is fast, and a material intermediate betweenFe,O, and y-Fe203 at low rates.290 The solubility product 291 and magneticsusceptibility 292 of ferrous hydroxide have been measured.Sublimation of ferric chloride in the absence of free chlorine gives aproduct containing small amounts of ferrous chloride in solid s0lution.2~~The formation of ferric chloride and calcium sulphate from ferric sulphateand calcium chloride is catalysed by both ferric chloride and traces of water,and is quite rapid above 300".294Work on the carbonitrides of iron and their reactions with ammonia andcarbon monoxide continues, and is of considerable interest in connectionwith industrial processes.295Basic nickel salts have been studied by precipitation at constant pH.296The preparation of pure nickel oxide has been examined in connection withexperiments onInterest in metal carbonyls and their derivatives continues, and manylaboratory preparations, which are greatly simplified by the use of dithionites(hydrosulphites) ,298 have been further improved by substituting formamidine-sulphinic acid for dithionite; e.g., the following reaction gives about an80% yield : 299 Ni2+ + (NH,),CSO, + 40H- + 4CO- Ni(CO), + SO,' +(NH,),CO + 2H20.75, 2495.283 V.J. Christensen, J. Kleinberg, and A. W. Davidson, J . Amer. Clzern. SOC., 1953,z84 A.v. Grosse, 2. Naturforsch., 1953, 8, b, 533 ; see also An?%. Reports, 1852, 49, 105.2 8 5 J. C. Hindman and P. Wehner, J . Amer. Chem. SOL, 1953, 75, 2869. 2873.286 B. Jezowska-Trzebiatowska, Trav. SOC. Sci. Lettres Wroclaw, 1953, B, 39, 5z 8 7 V. G. Tronev and S. M. Bondin, Doklady Akad. Nauk S.S.S.R., 1962, 86, 87.z 8 * D. Sen and P. RAY, J . Indian Chem. SOC., 1953, 30, 171, 181, 253.a89 A. W. Searcy and R. A. McNees, J . Amer. Chem. SOC., 1953, 75, 1578.z90 J. E. 0. Mayne, J . , 1953, 129.z91 D. L. Leussing and I. M. Kolthoff, J . Anzer. Chem. SOC., 1953, 75, 2476.2B2 J. Zernike, Rec. Trav. ckinz., 1953, 72, 390.2*3 H. Schafer and L. Bayer, 2. anorg. Chem., 1953, 272, 265.294 J. F. Hazel, W. M. McNabb, and W. D. Cooke, J . Amer.Chew&. SOC., 1953, 75, 1552.z95 W. K. Hall, W. E. Dietar, L. J. E. Hofer, and R. B. Anderson, ibid., p. 1442.z06 W. J. Singley and J. T. Carriel, ibid., p. 778. 297 G. Parravano, ibid., p. 1418.z98 E. 0. Fischer and W. Hieber, 2. ancwg. Chem., 1952, 269, 292, 305.299 Idem, ibid., 1953, 971, 229.(Chewt. Abs., 1953, 4'7, 9843)COATES AND GLOCKLING. 117Infra-red spectra and bond-length data for Ni(CO), and substitutedcarbonyls of the type (ligand),Ni(CO), indicate Ni-C double bonds andconsiderable double-bond character in the metal-ligand bonds.300 Theligands used were 2 : 2'-dipyridyl and o-phenylenebisdimet hylarsine.The dimeric cyanide of Ni(I), KqNi2(CN)6,301 absorbs carbon monoxidein solution, giving &[Ni(CN),CO] which reacts with acids according to theequation 302This reaction is strongly dependent on pH and follows the above equationonly at pH 7.This carbonyl cyanide and also K,[Ni(CN),(CO),] may beprepared, and isolated in pure form, by reactions in liquid ammonia.303The related iron compound has been prepared by the reaction 304Na,[Fe(CN),H,O] + CO ___t Na,[Fe(CN),CO] + II,OThe salt previously reported 305 as K,[Co(CN),CO] does not exist as such,but is a mixture of K3[Co(CN)J and K[Co(CO),]. Nickel carbonyl reactswith sulphur nitride in an inert solvent with precipitation of a black polymer :The latter slowly dissolves in several organic solvents, giving violet solutionsof the diamagnetic monomer, Ni(NS),.308Attention has been drawn to cobalt carbonyl hydride, Co(CO),H, whichis probably an active intermediate in reactions occurring in the presence ofcobalt catalysts between organic compounds and H,-CO mixtures at highpressures, since it gives very similar products to those obtained under actualhydroformylation conditions.307 It can be obtained pure and in high yieldby the action of pyridine on the readily available dicobalt octacarbonyl :Slow addition of this pyridine complex to dilute sulphuric acid liberatesCo(C0) *H.The proposed stabilisation of cobalt carbonyl hydride byhydrogen has been disproved, since there is no exchange with deuterium, andthe slow gas-phase decomposition is a second-order reaction. Althoughnot very soluble in water it behaves as a strong acid in titration with 0 . 1 ~ -sodium hydroxide.msThe reaction of dicobalt octacarbonyl with various bases has been studied.I t is remarkable that with dimethylamine a large proportion of the carbonmonoxide appears as dimethylformamide, and the rest according to theequationAt 220" and 200 atm.dimethylamine and piperidine are readily carbonylatedto the corresponding formamides, Me,N*CHO and C,H,,N*CHO, in thepresence of catalytic amounts of CO,(CO),.~O~4[Ni(CN),C0]2- + 2H,Of - Ni(CO), + 3Ni(CN),2- + H, + 2H20Ni(CO), + N,S,+ [Ni(NS),!, + 4CO12C5H5N + 3c02(co), __t ~ [ C O PY,][CO(CO),], + 8CO3Co,(CO), + 12Me2NH 2[Co(Me2NH),][Co(C0),1, + 8COR. S. Nyholm and L. N. Short, J . , 1953, 2670.301 R. Nast and W. Pfab, Naturwiss., 1952, 39, 300.302 R. Nast and T. von Krakkay, 2.anorg. Chem., 1953, 2'92, 233.,03 R. Nast and H. Roos, ibid., p. 242.304 W. Hieber, R. Nast, and C . Bartenstein, ibid., p. 32.305 W. Manchot and H. Gall, Ber., 1926, 59, 1056.a*5 M. Goehring and A. Debo, 2. anorg. Chem., 1953, 273, 319.307 I. Wender, H. W. Sternberg, and M. Orchin, 1. Arner. Chem. SOC., 1953, 15, 3041.ae* H. W. Sternberg, I. Wender, R. A. Friedel, and M. Orchin, ibid., p. 2717.309 Idem, ibid., p. 3148; W. Hieber, J. Sedlmeier, and W. Abeck, Ber., 1953, 86, 700118 INORGANIC CHEMISTRY.The anions Co(CO),- and Fe(CO),H- can be determined gravimetricallyas [Co phenan,] [Co(CO),], and [Fe phenan,] [Fe(CO),H]i which are insolublein ~ a t e r . 3 ~ ~Reactions in liquid ammonia have been used for the preparation of com-poundsof the types K,(NiR,), K,(NiR,), and K,(CuR,) in which R is an alkyneradical (-CiCH, -CiCMe, -CiCPh), e.g., [Ni(NH,)],(SCN), + 4PhCiCKK,[Ni(CICPh),]ZNH,. Loss of ammonia occurs in vacuo to giveK,[Ni(CiCPh),] as a yellow solid.This, with [Ni(NH,),](SCN), in liquidammonia, gives, on subsequent removal of ammonia, nickel(r1) phenylacetyl-ide Ni(CiCPh), as a black polymer. Potassium in liquid ammonia reducesK,[Ni(CiCPh),] to K,[Ni(CiCPh),], a compou'nd analogous to K,Ni(CN),.The reaction of cuprous iodide with potassium acetylide proceeds throughcuprous acetylide : 311CuCiCH + 2KCiCH __t K,[Cu(CiCH),]Important advances have been made in the study of metal biscyclo-pentadienyls, of which the orange-brown compound ferrocene " Fe(C,H,),was the first example.The red chromium,312 violet cobalt,313 and greennickel analogues have been obtained by an elegant method involvingreaction in liquid ammonia between an alkali-metal salt of cyclopent adieneand the appropriate metal ammine salt, followed by removal of ammoniain vacuo; e g . ,A striking feature of these compounds is their melting point, within a degreeof 173" in all cases. No doubt they are structurally very similar to the ironcompound, and, having practically identical exteriors, differ only in smallchanges in the atomic weight of the central atom, Cr, Fe, Co, Ni. Theyellow ruthenium compound Ru(C,H,),, reported last year, melts at 195.5" ;this rise in m. p. is likely to be due to ruthenium's being in a different periodfrom the former elements and differing substantially in atomic weight.Theiron compound is still the most stable.All the above compounds can be oxidised to singly charged cations,e.g., Ni(C,H,),+. Biscyclopentadienylnickel has also been obtained by theGrignard reaction : 315 C,H,MgBr + Ni(C,H,O,), _+c Ni(C,H,),, thoughthe corresponding reaction with the cobalt-acetylacetone complex orcobalt(I1) bromide leads to the cationic form Co(C,HJ2Br; the salt(Co(C,H,),) (BPh,) is quite insoluble. Stable biscyclopentadienyl-rhodiumand -iridium cations, analogous to Co(C,H.,),+, have been prepared. Thesalts are yellow and could not be reduced in aqueous media to the neutralcompounds.316 Titanium, zirconium, and vanadium tetrahalides react withcyclopentadienylmagnesium bromide to give cations of the type M(C,H,) ++.The titanium compound [Ti(C,H,),]Br, has been reduced to [Ti(C5H,),]Br.315These compounds are of considerable significance to chemistry, since they310 W.Hieber and H. Frankel, Bey., 1053, 86, 710.311 R. Nast, 2. Naturforsch., 1953, 8, b, 381.312 E. 0. Fischer and R. Jira, ibid., p. 1.314 E. 0. Fischer and W. Hafner, ibid., p. 444.318 G. Wilkinson, P. L. Pauson, J. M. Birmingham, and F. A. Cotton, J . Anzer. C]zem.316 G. Wilkinson, ibid., 1952, 74, 6148; F. A. Cotton, R. 0. Whipple, and G. Wilkin-[Ni(NH,),I(SCN), + 2KC5H, [Ni(NH3),I(C5H5), .__+ Ni(C,H,),a13 I d e m , ibid., pp. 217, 327.SOL, 1953, 75, 1011.son, ibid., 1953, '75, 3586COATES AND GLOCKLING. 119involve a quite unfamiliar type of covalent bonding, and like the higherboron hydrides and the metal-olefin compounds, can only be interpreted bymolecular-orbital methods (as opposed to the more readily visualised valency-bond treatment).It is no longer always possible to represent bonds inchemical formulze by drawing straight lines.Although aliphatic cc-di-imines are not known, their ferrous iodide com-plexes have been obtained in some instances, and provide an interestingexample of the stabilising effect of co-ordination.For example the crystalline salt (IX) has been isolated 1 ) from a mixture of ferrous iodide, diacetyl, and methyl-amine. The complex is hydrolysed by hot dilute acid,and both methylamine and diacetyl can be recovered (1x1almost quantitatively. The intense red colour of these compounds is similarto that of the well known 2 : 2'-dipyridyl complex, and it is suggested thatthe whole of the five-membered ring is conjugated by participation ofFe( 3 4 orbit als.,l7The equilibria involved in the formation of the FeSO,+ ion have beenmeasured a t 28" : 318/NMe=CH N(\NMe=CH 3[FeSO,+][Fe3+] [SO,-] = 95These results do not differ greatly from those calculated from kinetic dataon the oxidation of iodide by ferric ions in the presence of s ~ l p h a t e .3 ~ ~ Thereaction between potassium ferrocyanide and nitrosobenzene, in which theviolet ion [Fe(CN),,Ph*NOl3- is formed, is very strongly catalysed bymercuric ions even at ~O-'M.,~OFerrous-thioglycollic acid 321 and ferric-chloro-complexes have beenstudied; no FeC1,2- or FeClG3- ions are formed.322A series of cobaltammines [Co(NH,),(R-CO,)] (C104)2, where R rangesfrom CH, to C8H18, have been prepared by evaporating [Co(NH,),H,O] (ClO,),with R v C O , N ~ .~ ~ ~ The instability of iodopentamminocobalt (111) ions insolution is due to a reaction with iodide ions : 324Co(NH3),12+ + I- + Co(NH,),I+ + 1.Co(NH3),It + 6H,O __t CO(H,O),~+ + 5NH, + I-The heats of reaction of the successive replacement of H20 by Cl in the[CO(NH,),(H,O),]~+ and [Co en NH3(H20),-j3+ series of cations are much thesame, but entropy changes vary considerably.325Further examples of cobalt complexes with hexadentate ligands havebeen reported.326 The compound [Co tetren H20](C104)2, in which tetren istetraethylenepent amine, is paramagnetic, and evidently an ion-dipoleDoubt concerning the bonding in trisacetylacetonecobalt(II1)317 P.Krumholz, J . Amer. Chenz. SOC., 1853, 74, 2163.918 R. A. Whiteker and N. Davidson, ibid., p. 3081.320 S. ASperger, I. Murati, and 0. Cupahin, J., 1953, 1041.321 D. L. Leussing and I. M. Kolthoff, J . Amer. Chem. SOC., 1953, 75, 3904.922 G. A. Gamlen and D. 0. Jordan, J . , 1953, 1435.323 M. Linhard and B. Rau, 2. anorg. Chem., 1953, 271, 121.324 R. G. Yalman, J . Amer. Chem. SOC., 1953, 75, 1842.325 R. G. Yalman and (the late) A. B. Lamb, ibid., p. 1521.326 D. H. Busch and J. C. Bailar, ibid., p. 4574; F. P. D y e r , N. S. Gill, E. C.327 H. B. Jonassen and F. W. Frey, ibid., p. 1524.319 K. W. Sykes, J., 1952,124.Gyarfas, and F.Lions, ibid., pp. 1526, 2443120 INORGANIC CHEMISTRY.has been resolved by redetermining its magnetic moment.and is probably of the usual d2sp3 type complex.328[(ONO)Co(NH,),]X, __t [NO2Co(NH,),]X2 and related reactions variesgreatly with the anion for the solid compound, but not for the reaction indilute aqueous solution.329 The equilibrium between [CO(NH,),H,O]~+ and[Co(NH,) ,SO,]+ is almost independent of the sulphate-ion concentration ;this is ascribed to the presence of the former ion mainly as an ion-pairIt is diamagneticThe unimolecular velocity constant for the isomerisation[Co( NH,) 5H,0]3t*S042-.330Hvdrolysis of a series of C-substituted acetatopentamminocobalt (111)ions, ~R*CO,Co(NH,),]2+ with R = CH,, CH,CI, CCI,, CF,, 180 being used astracer, showed a gradual change in the position of bond fission from the C-0bond when R = CH, to the Co-0 bond with R = CF3.331Spectrophotometric examination of the chloro- and aquo-complexes ofCO(II) and Ni(I1) in octan-2-01 revealed the species CoCl+, CoCl,, CoCl,-,COC~,~-, and some evidence was obtained for the existence of an unstablecoloured chloro-complex ofThe influence of various agents, both complexing and non-complexing, onthe polarographic reduction of the hexamminocobaltic( 111) ion has beenexamined.333A study of the rate of aquation of trans-[Co(AA),Cl,]+ ions, in which thesteric properties of the bidentate group AA were varied, favours the S N 1dissociation mechanism involving a five-co-ordinated intermediate ratherthan the SN2 or displacement mechanism with a seven-co-ordinated inter-mediat e.334Compounds in which elements have the co-ordination number Jive areparticularly interesting since this number is uncommon, and two differentsteric arrangements of five bonds have been recognised.Recently, a numberof diamagnetic crystalline compounds of the type [Co( RoNC) ,]X have beenprepared in which R is an aryl group and X = I- or C10,-. These are1-1 electrolytes and the cobalt atom is no doubt isoelectronic with the ironin Fe(CO),, since carbonyl and isocyanide groups appear to combine withmetals in much the same way using essentially double bonds : compareNi(CO), and N~(RoNC),.~,~The species Ni(SCN)+, Ni(SCN),, and Ni(SCN),- have been identified innickel thiocyanate solutions in which the thiocyanate concentration ise 0 - 5 ~ ~ ~ ~ ~The Platinum Metals.-( 1) Ruthenium, osmium, rhodium, and iridium.Apyrosulphate of ruthenium, Ru(vI)O,S,O,, has been obtained from thetetroxide and sulphur trioxide.,,,328 R. 0. Whipple, R. West, and K. Emerson, J., 1953, 3715.329 B. Ardell, 2. anorg. Chem., 1952, 271, 49.330 H. Taube and F. A. Posey, J . Amer. Chem. Soc., 1953, 75, 1463.331 C. A. Bunton and D. R. Llewellyn, J . , 1953, 1692.332 W, D. Beaver, L. E. Trevorrow, W. E. Estill, P. C . Yates, and T. E. Moore, J .333 H. A. Laitinen and P. Kivalo, ibid., p. 2198; H. A. Laitinen, A. J. Frank, and334 R. G. Pearson, C. R. Boston, and F. Basolo, ibid., p. 3089.835 L. Malatesta and A.Sacco, 2. anorg. Chem., 1953, 273, 247.336 S. Fronaeus, Acta Chem. Scand., 1953, 7, 21.337 M. A. Hepworth and P. L. Robinson, J., 1953, 3330.Amer. Chem. SOC., 1953, 75, 4556.P. Kivalo, ibid., p. 2865COATES AND GLOCKLING. 121Several new co-ordination compounds of osmium have been prepared,eg., some penta- and hexa-ammino-osmium( 111) complexes,338 a para-magnetic Os(v) salt,33s and the thiourea complex ions [OS(III) (NH,°CS*NH2)6]3fand [OS(VI)O,(NH,*CS*NH,) 4] ++ .340An orange-yellow monomeric rhodium trisacetylacetone complex, m. p.260", subliming at 240" (1 mm.), and a yellow iridium analogue, m. p. 269",also volatile, have been obtained from Rh(m) nitrate and K,IrCl, respec-tively. These compounds deposit rhodium and iridium mirrors at 280-290°.341 Chemical or anodic oxidation of iridium(iI1) salts gives bluish-violet solutions containing the IrO*OH+ ion, and finally IrO,++. Reductionof the latter proceeds through an unstable form of Ir(rv), probably IrO++,Some cyclopentadienyl compounds of rhodium and iridium have beenmentioned earlier (p.1 18).(2) Palladium and $latinurn. Although platinum is well known to resistaqueous hydrochloric acid, attack occurs in the presence of those chlorides(e.g., KC1, CsC1) which form insoluble chloroplatinates, since the equilibrium-normally favourable to metallic platinum-is disturbed by separation ofthese salts. Gaseous hydrogen chloride also attacks platinum in the pres-ence of fused potassium chloride with the formation of K,PtCl,, whichdisproportionates to platinum and K,PtC1, onThe small number of cis-complexes of palladium has been extended bythe preparation of a series of cis-(SbR,),PdCl, compounds, advantage beingtaken of the low solubility of the highly polar cis-isomers in non-polarsolvents.cis-Isomers could not be prepared from phosphines and arsines,since the cis-trans-equilibrium lies very much in favour of the transformexcept when antimony is the donor.344 trans-Elimination reactions ofPdA,Cl, with sodium nitrite (A = aliphatic amine) are influenced by thesize and basicity of A.345More fluoropalladates 346 and fluoroplatinates 347 (M2PdF, and M,PtF,)have been described, as well as fluoroplatinic acid hydrate.3448Several palladium(I1) and platinum(I1) complexes with monoximes (e.g.,acetoxime) have been investigated.349 A hexamminoplatinum(1v) complex[Pt(NH,),](SO,), has been prepared by the action of ammonia and ammoniumsulphate on the methylamine compound [Pt (CH,*NH,),C1,]C1,.350 Theplatinum(1v) complex ion [Pt en2C1,I2+ has been partially resolved intooptical is0mers.3~~to 1ro.o~f.342338 F.P. Dwyer and J. W. Hogarth, J . Proc. Roy. Soc. N.S.W., 1950, 84, 117,33s Idem, J . Amer. Chenz. SOG., 1953, 75, 1008.340 R. D. Sauerbrunn and E. B. Sandell, ibid., p. 3554.341 F. P. D y e r and A. M. Sargeson, ibid., p. 984.342 F. P. Dwyer and E. C. Gyarfas, J . Proc. Roy. SOC. N.S.W., 1950, 84, 123.s43 H. von Wartenberg, 2. anorg. Chem., 1953, 273, 91.344 J. Chatt and R. G. Wilkins, J.. 1953, 70.345 H. B. Jonassen, T. 0. Sistrunk, J. R. Oliver, and G. F. Helfrich, J . Amer. Chem.347 T. P. Perros and C. R. Naeser, J . Amer. Chem. Soc., 1953, 75, 2516.348 R. S. Clarke and T. P. Perros, ibid., p. 5734.349 A. V. Babaeva and M. A. Mosyagina, Doklady A k a d . N a u k S.S.S.R., 1953, 89, 293;A. V. Babaeva and I. I. Lyuboshits, ibid., p. 681.350 K. I. Gil'dengershel, Zhur. Priklad. Khim., 1950, 23, 487.35L J. F. Heneghan and J. C . Bailar, J . Amer. Chem. SOL, 1953, 75, 1840.1952, 85, 113.SOC., 1953, 75, 5216. 346 A. G. Sharpe, J., 1953, 197122 I X 0 RG AN I C C €1 B M I STR I’ .The bridge bonds in the compound (PrT1,P),Pt,(SEt),C1, are sufficientlystable to have allowed the isolation of cis- (X) arid trans- (XI) forms, of whichE t(X) p = 1 0 . 3 ~4. Etthe cis-isomer is thermodynamically the more stable in benzene solution.This is also true for the bridged monothio-complex(Prn,P)ClPt(SEt)ClPtCl(PPrn,)The corresponding palladous complexes isomerise in benzene solution,though the cis-form predominates at eq~ilibriurn.~~z These results areparticularly interesting since it is the first time that cis- and trans-isomersof bridged complexes have been separately isolated ; normally only thctrams-form crystallises from solution.The long-standing uncertainty about the structure and bonding of theplatinum-olefin compounds appears now to be largely resolved.353 Theinfra-red spectra of several of these compounds, for which greatly improvedpreparative methods have been devised, indicate that the olefin retains itsdouble bond in the complex and is syininefricaEZy bonded to the platinum.This result, together with the observation that olefins behave as stronglytrans-directing ligands, suggests that the metal is bonded to the olefin byboth G and x bonds. The total (Pt-olefin) bond order is estimated at about4/3, and would seem to involve a G type of bond between a Pt(dse2) orbitaland the olefin bonding x orbital together with a x type of bond between#-Type bond @ ~ T y o t ? bonda Pt(dfi) orbital and the olefin antibonding X* orbital, the symmetries beingcorrect for these combinations.354 All of the properties of olefin complexescan be explained, at least qualitatively, in terms of this structure.355352 J. Chatt and F. A. Hart, J., 1953, 2363.353 J . Chatt and L. A. Duncanson, J., 1053, 2939.s54 M. J. S. Dewar, Bull. SOC. chim., 1951, 18, C79.955 J . Chatt, “ The General Chemistry of Olefin Complexes with Metallic Salts;Cationic Polymerisation and Related Complexes,” Heffer, Cambridge, 1053, p. 40COATES AND GLOCKLING. 123Some olefin complexes of platinum(I1) have been obtained in which oneolefin molecule appears to occupy two co-ordinationC ~ ~ ~ - C J & ~ > C ~ positions. The compound (XII), for example, isI monomeric in bromoform and its dipole moment, 6 D,c H z - c H ~ ~ H ) ~ ~ is consistent with the c i s - s t r ~ c t u r e . ~ ~ ~ A similar mono-meric and polar (p = 7 D) compound PtI,,C,H, wasprepared from cyclooctatetraene ; 357 two co-ordinatebonds a t right angles could readily be formed only from the " tub " form ofthe hydrocarbon, in confirmation of recent electron-diffraction data.358It would be expected from the picture of metal-olefin bonding reportedabove that substituted acetylenes would form complexes with platinouschloride. Attempts to prepare platinous complexes of dimethyl- anddiphenyl-acetylene gave some evidence of complex formation, but the com-pounds formed underwent rapid autoreduction to the metal and could notbe isolated.355The main product from the reaction between methylmagnesium iodideand platinum(1v) chloride is trimethylplatinum iodide, but Me,Pt, Me,Pt I,,MePtI,, and MePtI, have also been isolated from the complex reactionmixture. Tetramethylplatinum is obtained from Me,PtI and methyl-sodium, whereas metallic potassium affords hexamethyldiplatinum Me,Pt,,which is monomeric in benzene solution.359:Pt(XII)G. E. COATES.F. GLOCKLING.3513 K. A. Jensen, Acta Chem. Scand., 1953, 7, 866.357 Idem, p. 868.358 I. L. Karle, J . Chem. Phys., 1952, 20, 65.359 H. Gilman, M. Lichtenwalter, and R. A. Benkeser, J . Amer. Chem. SGG., 1953,75, 2063