14 ABSTRACTS OF CHEhIICAIi PAPERS.In o r g a n i c C h e mi s t r y .Dispersion-equivalent of the Diamond. By A. SCHRAUF(Ann. Phys. Chern., 22, 4 2 6 4 2 9 ) .-The dispersion-equivalen t of a,Brazilian diamond, determined by the author, was 0.03286. He dis-cusses the extreme smallness of this number as compared with thesame constant in some series of organic bodies, which show anincrease of its value with increase of the proportion of carbon.XI. R.Liquid Carbonic Oxide. By V. OLSZEWSKI (Compt. rend., 99,706--707).-Carbonic oxide carefully purified from carbonic anhy-dride forms a transparent colourless liquid under pressure between- 139.5" and - 190°, but in a vacuum it solidifies a t - 21 1" to a snow-like mass, if the pressure has been reduced rapidly, but to a compactopaque mass if the pressure has been reduced slowly. If the pressure isreduced so gradually that the liquefied gas does not boil but evaporatesonly from the surface, the liquid forms a transparent solid. Whenthe pressure rises to one atmosphere the solid melts to a colourlessliquid. The following table shows the relation between the pressureand the boiling point of liquid carbonic oxide :-Pressure inatmos.Temp.35.5 - 139.5" (critical point)25.7 - 145.323.4 - 147.721.5 - 148.820.4 - 150.018.1 - 152.0Pressure inatmos. Temp.16.1 - 154.4"14-8 - 155.76-3 - 168.24.6 - 172.61.0 - 190.0Vacuum - 211.0 (solidifies)Although, in the gaseous state, carbonic oxide resembles nitrogen inmany of its properties, the two substances behave somewhat differ-ently a t very low temperatures.The critical point of carbonic oxide,and its boiling point under atmospheric pressure, are several degreeshigher than those of nitrogen. Carbonic oxide solidifies in a vacuum,but a low temperature alone is not sufficient to solidify nitrogen.Moreover, the temperature obtained by the evaporation of liquid car-bonic oxide in a vacuum is higher than that obtained by the evapora-tion of liquid nitrogen under the same conditions. The differenceIX'ORGAK'JC CHEMISTRY 1 5are doubtless due to the presence of a solid element in the carbonicoxide. C. H. B.Phosphorus Trifluoride. By H. MOISSAN (Cm7pt. rend., 99,6jr;-657).-Phosphorus trifluoride is obtained by heating carefullydried copper phosphide with lead fluoride free from silica, in a brasstube, and drying the product over pumice moistened with sulphuricacid.It is a colourless gas which does not liquefy under a pressureof 180 atmos. at 24", but under a pressure of 40 atmos. at -10" formsa colourless very mobile liquid, which does not attack glass. Thesp. gr. of the gas is 3.022 (calculated 3.0775).Phosphorus trifluoride is incombustible when mixed with air, but ex-plodes when it is mixed with b.alf its volume of oxygen and brought incontact with a flame or electric spark. When pure, it does not fumein the air, but it is decomposed slowly in presence of water at theordinary temperature, with formation of hydrofluoric and phosphorousacids, PI?, + 3H,O = H,PO, + 3HTp.When mixed with steam at loo",the decomposition of the fluoride is mnch more rapid. Solutions ofsodium o r potassium hydroxide rapidly absorb the trifluoride, withelevation of temperature and formation of a fluoride and a phosphite.Solutions of barium hydroxide o r potassium carbonate absorb the gasmore slowly. Phosphorus trifluoride is immediately decomposed bysolutions of chromic acid or potassium permangannte, and is instantlyahsorbed by bromine. It is also absorbed by alcohol with developmentof heat, and is not given off again when the liquid is boiled. Whenpassed over boron or silicon at a dnll red heat, it yields boron or siliconfluoride, and it is rapidly decomposed by melted sodium, more slowlgby heated copper. It combines with ammonia gas, forming a verylight, woolly, white compound, which is decomposed by water.When mixed with half its volume of oxygen and subjected t o theaction of an electric spark, phosphorus trifluorids explodes violently,and the compound formed fumes in the air and is instantly absorbedby water with formamtion of phosphoric acid, but no trace of phos-phorous acid.The gas thus produced seemed to be phosphorus ox)--fluoride, PF,O.When heated in contact with glass, phosphorus trifluoride is de-composed with separation of phosphorus and formation of siliconfluoride, and the volume of the silicon fluoride thus formed furnishesa means of estimating the amount of fluorine in the phosphorusfluoride. C. El. B.Phosphorus Chloronitride. By A.W. HOFJIANN (Bey., 17,1909-1912) .-The formula for this body has long been established asP3N3CIS, but Iittle work has been done on the subject. The aut,horhas made experiments to determine whether the chlorine-atoms canbe replaced by other radicals.Aniline dissolves this chloroni tride to a clear solution, which, how-ever, soon solidifies to a, crystalline mass. The principal products area crystalline substance, very sparingly soluble in alcohol, and anamorphous compound, easily soluble. The crystalline substance isbest purified by solution in glacial acid. It yields well-formed needle16 ABSTRACTS OF CHEMICAL PAPERS.melting at 268", a,nd has the formula P3N3(NHPh),.would be expressed by the equation-Its formationP3N3CL + 12NHPh = P,N,(NHPh), + 6NHSPhCl.Paratoluidine yields a similar crystalline compound, melting a t 243".Piperidine acts stron gly with the chloronitride, producing piperidinechloride and an amorphous substance, easily soluble in alcohol, insolu-ble in water.The author is inclined to look upon the group P3N3 as playing animportant part, and to consider that the formula of phospham shouldbe trebled, and would then become P,N,(NHj",. This would beanalogous to an aniline compound, P3N3( NPh)",.The substance,I',N,(NHPh), described above gives off aniline when heated, and leavesa resinous mass, which mag contain the compound, P,N3(NPh) "3.It is also probable that other ammonio-derivatives might be pre-pared somewhat according to the following equations :-3PC& + 3NH3 = P,N,Clp, + 9HC1SPCI, + 9NH3 = P3N,(NH,)6 + 15HC1.3PC15 + 6NH3 = P3N3(WH)", + 15HClL.T. T.Action of Nitric Acid 011 Tellurium. By D. KLEIN and J.MOREL (Compt. rend., 99, 540-542).-Pulverulent tellurium, obtainedby precipitation with sulphurous acid, dissolves readily in dilute nitricacid, with evolution of nitrogen oxides. The temperature at whichsolution takes place is lower the higher the concentration of the acid ;with acid of sp. gr. 1-25 the action begins a t - 11". At a low tem-perature solution is not complete, and a greyish curdy residue is left,which afterwards turns white, and forms long flexible microscopicneedles containing both nitric and telluric acid. The solution,when diluted with water, deposits " tellurous hydrate " or telluronsanhydride, a certain quantity of basic tellurium nitrate (Abstr., 1884,p.1256) always remaining in solution. " Tellurous hydrate " isformed when the nitric acid is dilute (sp. gr. 1.1-1.2) and the actiontakes place a t a low temperature. It is a white curdy substancewhich gradually changes to a yellowish-white mass of microscopicrectangular lamella of tellurous anhydride ; these act strongly onpolarised light. When the reaction takes place a t a higher tempera-ture, or if stronger nitric acid is used, tellurous anhydride is formedi n microscopic quadratic octahedra. The nitric acid solution spon-taneously deposits octahedral crystals of tellurous anhydride, and ifthe nitric acid employed is somewhat dilute (sp.gr. about lee), andthe temperature has not risen above 30" during the reaction, the pre-cipitntion of tellnrons anhydride is accelerated by heat. Under theseconditions, about half the tellurium remains in solution in the form ofnitrate, which crystnllises out when the liquid is concentrated andcooled. When the octahedral crystals of teilurous anhydride areboiled with nitric acid of sp. gr. 1.35, they yield a solution of thebasic nitrate.Tellurous anhydride requires 150,000 parts of water for solution.C. H. BINORGANIC CHEMISTRY. 17Action of Water and Nitric Acid on Basic TelluriumNitrate. By D. KLEIN and J. MOREL (Compt. rend., 99, 567-569).-Basic tellurium nitrate (Abstr., 1884,1256) is slowly decomposed bywater in the cold, nitric acid and a very small quantity of telliirousanhydride being dissolved, whilst tellurous anhydride is left undis-solved in rectangular lamella At a higher temperature, decompositionis almost instantaneous ; the solution becomes strongly acid, and thegreater part of the tlellurous anhydride remains undissolved in theform of microscopic octahedra.These facts explain the commonlyaccepted statement that tellurous anhydride is slightly soluble i nwater, but does not redden blue litmus. Tellurous nitrate does notact on moistened litmus in the cold until after several hours, andwhen decomposition takes place the solution of a small quantity oftellurous anhydride is due to the presence of the free nitric acid.Basic tellurium nitrate dissolves in nitric acid and crystallisesreadily when the solut\ion is concentrated and cooled. It seems to bemuch more soluble in the dilute than in the concentrated acid. Solu-tions in nitric acid of sp.gr. 1.1-1-4 are stable a t all temperatures,and solutions in acid of sp. gr. about 1-35, are not decomposed onaddition of 100 vols. of water. On the other hand, solutions in nitricacid of sp. gr. 1.1 are decomposed by water with precipitation of tel-lurous anhydride, decomposit'ion being more rapid the greater theproportion of water. The limit of decomposition appears to be reachedwhen the solution is mixed with 5 vols. of water; under these con-ditions, the precipitation of tellurous anhydride is very slow, and witha smaller proportion of water no decomposition takes place.Thetellurous anhydride deposited when the nitric acid solutions arediluted, does not crystallise in octahedra, but in some perfectly dis-tinct form.Basic tellurium sulphate, (TeOJ2S0,, decomposes in a similarmanner. C. H. B.Preparation of Potassium Chlorate. By E. K. MCSPRATT andG. ESCHELLMANN (Dingl. polyt. J., 254, 90).-Chlorine is passed intomagnesia mixed with water, and the solution is evaporated to 35-50" B., so that, on cooling, sorne magnesium chloride crystnllises out.The product is now treated with potassium chloride, when potassiumchlorate and magnesium chloride are formed ; the greater portion ofthe former may then be obtained by crystallisation. The mother-liquor, which retains 5-10 per cent. of the total potassium chlorate,is treated with hydrochloric acid and steam, by which potassiumchloride is formed and chlorine is evolved; the latter may be ab-sorbed by lime or magnesia.The solution containing an excess ofacid is now neutrnlised with magnesium carbonate, and a solution ofmagnesium chloride containing potassium chloride is formed. Thisis evaporated to 45" B., and allowed to cool, when it sets. In thisstate, it may go into commerce, or magnesia may be obtained from itby heating, and thi,s can again be employed in the process. J. T.By E. R. MUSPRATT andG. ESCHELLMANN (Dingl. polyt. J., 254, 47).-Chlorine is pused toPreparation of Sodium Chlorate.YOL. XLT~II. 18 ABSTRACTS O F CHEMICAL PAPERS.saturation into water holding magnesia in snspension, so that oneequivalent of magnesium chlorate to 5-54 equivalents of chloride gointo solution.This solution can be concentrated by evaporation to35-40' B., so that on cooling a part of the chloride crystallises out.The solution, now containing four equivalents of chloride to one ofchlorate, or the original solution if preferred, is treated with sodiumlivdroxide or carbonate, or a mixture of the two. Magnesia, mag-nesium carbonate, 013 a mixture of t-he two, as the case mav be, isprecipitated whilst sodium chloride and chlorate remain in solution.On concentrating by evaporation to 48-50' B., and cooling, thechlorate separates out. The magnesia residue is employed againdirectly, o r if it contains carbonate, after being calcined. J. T.Crystallised Argentammonium Chloride and Bromide.ByTERREIL (Bu71. SOC. Chim., 41, 597).-Argentammonium chloride andbromide were obtained in a cr-ystalline form by heating the dry salts,saturated w i t h ammonia gas, with a strong aqueous solution of ammo-nia in sealed tubes. The method, as well as the properties of thecrystals, have been described in a former Abstract (Abstr., 1884, $90).Note by Ahsfmetor.-The author states that the argentammoninmchloride and bromide have never before been crystallised. This,however, is incorrect. Faraday, in 1818 (Journ. Science arzd Arts, 5,74), obtained a crystalline argentamnionium chloride by dissolvingsilver chloride in strong solution of ammonia and allowing the liquidto stand. Transparent crystals $inch wide were deposited in flatrhombohedra, i n some of which two acute angles were missing, whichcaused them to appear like hemihedra.The crystals lost ammoniaand became opaque when exposed to air, and were similarly decnm-posed by water with separation of silver chloride. An argentammo-niuru bromide having analogous properties, was prepared in the sameway by Liebig (Schweig. Journ., 48, 103).-W. R. n.W. R. D.Argentammonium Phosphate. By 0. WIDMANN (Bey., 17, 2284-228.5) .-With reference to Reychler's communication on this sub-ject (Abstr., 1884, l261), the author states t h a t in 18'14 he described(Oej'ers. of Konyl. Vet. Ahad. F6i-handlingar, Stockliolm, 1874, No. 4,p. 41), a crystalline cliammonio-silver phosphate, AgjP04,4NH,. It wasobtained by evaporating an amznoniacal solution of silver phosphatein a desiccator over quicklime with which a little ammonium chloridehad been mixed.It formed coloiirless prismatic needlps resemblingthe arsenate. The probable constitution is AgO.PO(ONH,.NH,Ag),.The crystals turn yellow on exposure to the air, and give up all theirammonia over sulpliuric acid. With ammonia and dry silver phos-phate, the author obtained results similar to Reychler's.L. T. T.Argentammonium Compounds. By A. R EPCHLER (Rer., 17,2263 -22G6).-Ammonia is rapidly absorbed by silver citrate withconsiderable development O E heat and a discoloration of the salt :about 4-5 mols. NH, are thus absorbed. Silver citrate dissolveINORGANIC CHEMISTRY. 19readily in ammonia, and alcohol precipitates from this solution hex-immoizio-silver citrate as a thick syrup, easily soluble in water. Silverbenzoate absorbs dry ammonia to form diammonio-sihter benzoate, awhite substance insoluble in water.Carey-Lea has described (Chein.News, 1861) a yellow crystalline diammonio-silver picrate. Thepower of the picrate to absorb ammonia is probably due to its nitro-groups. Ammonium picrate absorbs 1 mol. NH, at 0" to form ~"IZOH-ammonio-ammonium picrate, C6H2(N03) 3.0NH,NH3 : a t summer heat(about 26") scarcely a trace of ammonia is absorbed.The author considers the constitution of the diammonio-comnouncls I R--.of the organic acids to be probably Okg > C < g z : , and of the mono-nmmonio-compounds, where he considers the nitro-group to be thedetermining agent, to be (taking AgN0,,NH3 as an example)Agoammonia united to the silver.L. T. T.0 >N<gg2 or Ago>N\A 0 pH, , and that in neither case is thePreparation of Strontium and Barium Chlorides. ByWACKENRODER (Dingl. poZyt. J., 253, 440).-The author proposes toadd to a solution of str.ontium o r barium sulphide an equivalentamount of calcium chloride, and pass- carbonic anhydride into themixture. Hydrogen sulphide is disengaged and a solution of strontiumor barium chloride obtained, whilst calcium carbonate is precipitated ;the latter is removed by filtration, and the solution evaporated andallowed to crystallise. D. B.Constitution oP Bleaching Powder. By E. DBKYFUS ( B d l .Xoc. Clzim., 41, 600-609) .-The formula proposed by Stahlschmidt(2CaHC10, + CaCI, + 2H,O) alone accounts-for the excess of calciumhydroxide that is invariably present in this compound.Assumingthis formula, bleaching powder should contain 39.01 per cent'. ofavailable chlorine, but experiment sliows that it often contains morethan 40 per cent., which appears to militate against the nssamption.But the use of moist lime in the maiinfaeturing process explains thisresult. The water acts on the bleaching compound CaHClO,, pro-ducing calcium hypochlorite, together with free calcium hydroxide,2CaHC102 = Ca(OH), + Ca(CIO),. The calcium hydrovide thenagain combines with chlorine. According t o this, the active cornpoundir! bleaching powder is CaHClO, with' more or less calcium hypo-chlorite.Stahlschmidt's formula also supposes the existence of cal-cium chloride in bleaching powder. This has been considered to beincorrect, as bleaching powder is said not to yield calcium chloridewhen treated with alcohol. The author dispute8 this assertion, andstates that calcium chloride is always diwolved from the compound byalcohol, in quantity which increases with the time during which thoalcohol is in contact. Lunge and Schappi (Abstr., 1880, 789),a:guing from the action of carbonic anhydride on bleaching powder,whereby nearly the whole of the chlorine is evolved, have also arrivedat the conclusion that calcium chloride is not a constituent of bleachingc 20 ABSTRACTS OF CHEMICAL PAPERS.powder. The author points ouk that this conclusion is erroneous ; foralthough carbonic anhydride does not act on calcium chloride alone,yet in presence of hypochlorous anhgdride (from the action of car-bonic anhydride on CaHC102), the following reaction occurs eitherwith dry calcium chloride or with its aqueous solution: CaCl, + CO, + C1,O = CaC03 4- 2CL.In order to determine that the calciumhydroxide precipitated by water from bleaching powder is an essentialconstituent, the following expeyiments were made :-Solid bleachingpowder was treated with ammonia and alcohol ; the liquid was boiled,filtered, diluted with water, and the calcium estimated as oxalate. Inanother experiment, dry bleaehing powder was melted at a red heatto expel oxygen and chlorine ; the residue, treated with alcohol andwater, was filtered, and the calcium estimated in the filtrate as oxa-late.The results of these two experiments, which determine t8heamount of calcium as chloride, were identical. It is further shownthat with two carefully prepared specimens of bleaching powder, thecalcium obtained as chloride by the ammonia method is just half ofthe total calcium combined with available Chlorine, the other halfhaving been precipitated as hydroxide. This is in accordance withthe following equations :--2[2(CaHC10,) + CaC12] + 2NH,.OH= 8NH4C1 t 3CaCL + 3Ca(OH), + 202, and at a red heat2[2(CaHC10,) + CaCl,] + H20 = 3CaC1, + 3Ca(OH)2 + C1, + 30.The author concludes, therefore, that the formuala of bleachingpowder should be written 2CaHC10, + CaCl, + 2&0.Peroxides sf the Zincmagnesium Group.By R. HAASS(Ber., 17, 2249-22.55).-Th&-1ard (Ann. Chim. Phys., 1818, 9, 53,and Mdm. d e l’L4cad. des Sciences, 3, 429) described the formation of a“deutoxide de zinc” by (A) solution of zinc hydroxide in a hydro-chloric solution of hydroxyl, and reprecipitation with potash or soda,and (B) by acting directly on gelatinous zinc hydroxide with hydroxyl.On estimating the excess of oxygen in his compounds, Thenard foundthat the additional oxygen taken up was rather more than half thatoriginally present in the monoxide ; and concluded from this that theperoxidation was incomplete. These results appear to 11ave been verygenerally overlooked, o r when noticed (as in Gmelin-Kraut’s Hand-book), mistrusted. The author has therefore repeated ThBnard’sexperiments and fully confirms his results.The author employed the methods used by ThBnard, but modified(A) so far as t o mix a solution of a pure zinc salt, with an aqueoussolution of hydroxyl, and then precipitate with ammonia.The authorwas not able to obtain the pure peroxide, the precipitate always con-taining unosidised zinc hydroxide, The composition of the preci-pitate dried a t 110”, varied between Zn,08 and Zn,O,. By numerousmodifications of the mode of preparation, the author endeavoured toobtain the peroxide free from the hydroxide, but in every case wherethe precipitation of hydroxide was avoided, no formation of peroxidetook place, so that the author is inclined to eonsider the presence ofhydroxide as essential to such formatioaAs rightly described hy Thdnard, zinc peroxide (or rather its mix-ture with the monoxide) is a white, odourless, tasteless, and neutralW.R. DINORGANIC CEEMISTRT. 21gelatinous mass. This substance is tolerably stable towards wat3r,acids, and heat. A sample which had been heated a t 120" for 12 hours,and subsequently more strongly heated in a test-tube, still gave thehydroxyl reaction very strongly when dissolved in hydrochloric acid.The author has also obtained similar results with cadmium, the com-pounds obtained varying between Cd50s and Cd305, Manganese,which in other ways may be easily converted into the dioxide,yielded by t,he above treatment results almost exactly agreeing withthose obtained with zinc and cadmium.The composition of the pre-cipitates varied between Mn,O, and &iInsOe. Magnesium appears toform a similar peroxide, but with more dif€iculty, the highest stage ofoxidation yet obtained being expressed by MgO : Op = 93 : 7, whereOp represents the additional oxygen. Up to the present, no evidenceof the existence of a peroxide of beryllium could be obtained.By DEBRAY andJOANNIS (Compt. ~ e u d . , 99, 533--587).-1t is well known that cupricoxide is decomposed when strongly heated, and it is generally believedthat the product of decomposition is an oxide, Cuj03, or Cu50p, inter-mediate between euproua and cupric oxides.If cupric oxide yields the oxide CujOI when heated, it aught t ohave a constant tension of dissociation until one-fifth of the oxygenhas been expelled, a t which point the tension will change to'bhat ofthe intermediate oxide ; but if, on the other hand, the cupric oxide isdecomposed simply into cuprous oxide and oxygen, and the se-calledintermediate oxide is really a iniature of these two bodies, khetensioriof dissociation of the cupric oxide should remain constant until halfthe oxygen is expelled, a t which point it will change to that of thecuprous oxide.Direct expeyiments show that when cupric oxide is heated in a,vacuum, it begins t o decompose at a dull red heat, and if the tempera-ture is so regulated that the oxide does not fuse, the tension of disso-ciation of the latter remains constant until very nearly half of theoxygen is expelled.If the apparatus is allowed t o cool, any oxygenremaining within i t is cowzpletely absorbed by the cuprons oxide, andwhen the residue is cold, it is found to consist of cuprous oxide i nthose parts which have been most strongly heated, and of cupricoxide in those parts which have been somewhat cooler, the line ofseparation of the two oxides being perfectly sharp and distinct. Thesame results are obtained with various samples of cupric oxide pre-viously partially decomposed by fusion. It follows, therefore, thatwhen cupric oxide is heated under these conditions, it is decomposedinto oxygen and cuprous oxide only, without forming any inter-mediate oxide.If the cupric oxide is heated to fusion, it is decomposed somewhatrapidly, b u t the tension of dissociationt-aries with the state of decom-position of the oxide, and diminishes rapidly as the residue becomesmore completely converted into cuprous oxide. When the partiallydecomposed oxide is allowed to cool slowly in the apparatus, the pres-sure of the oxygen diminishes until the moment of solidification,when it suddenly increases, quickly attains a maximum, and then, asL. T.T.Decomposition of Cupric Oxide by Heat22 ABSTRACTS OF CHEMICAL PAPERS.cooling continues, diminishes again, finally becoming nil if theabsorbing sureace is sufficiently large. These phenomena are easilyexplained if it is admitted that the dissolution of a dissociable body ina liquid incapable of combining with it lowers the tension of dissocia-tion of that body in the same way as the vapour-tensions of liquidsare modified when certain liqnids are mixed.On this assiimption, thetension of dissociation of cupric oxide, fused with an increasing pro-portion of cuprous oxide, diminishes as the proportion of cuprousoxide increases ; but when the residue solidifies and forms a mixtureof the two oxides which do not act on one another, tbe cupric oxideregains its original properties, and more especially its true tension ofdissociation, hence the sudden increase of pressure at this point.By DEBRAY and JOANNIS (Compt. rend.,99, 688--692).-When copper is heated in presence of air, it is con-verted in to cupric oxide without intermediate dormation of cuprousoxide, at all temperatures between that a t which oxidation begins(about 350"), and that a t which the tension of dissociation of theoxide formed amounts to one-fifth of the atniospheric pressure, i.e.,the pressure of the oxxgen in the air.Beyond this temperature, thecupric oxide a t first formed is partially decomposed, and when themixture of cuprous and cupric oxide melts, decomposition ceases assoon as the variable and diminishing tension cf the oxygen in themixture amounts to one-fifth of the atmospheric pressure. The com-position of the mixture will depend on the temperature. A similarresult is obtained by direct oxidation of copper at these high tem-peratures ; a fused product is always obtained consisting of a mixtureof cuprous and cupric oxides, in proportions varying with the tem-perature.If the partially decomposed oxide is allowed to cool in the air, it iscompletely reoxidised if sufficiently porous ; but if it has been fused,oxidation takes place only on the surface, and the solidified residuehas practically the same composition as the liquid.It is evident thatin determinations of copper as cupric oxide the temperature must notbe suEcient t,o melt the oxide.When the copper is present in large excess, the product of oxida-tion is cupric oxide alone, if the temperature is below redness ; but ift,he t,emperature is sufficiently high to partially dissociate the cupricoxide, t,he latter is decomposed into cuprous oxide and oxygen, andthe oxygen thus given off a t once combines with the excess of copper,forming a further quantity of cuprous oxide. A mixture of cupricoxide and metallic copper cannot in fact exist at a temperature atwhich the oxide begins to dissociate, for the oxygen given off is atonce absorbed by the metallic copper, and thus is prevented fromacquiring a tension sufficiently high to arrest decomposition.I n cases where the amount of oxygen is not sufficient to oxidisethe copper completely, but is more than sufficient to convert it intocuprous oxide, the product is a mixture of the cuprous and cupricoxides (preceding Abstract).Cuprous oxide absorbs oxygen evenmore readily than metallic copper ; hence if the preceding mixture isallowed to cool in air or in oxSgen, the cuprous oxide is completelyC. H.B.Oxidation of CopperINORGANIC CHEMISTRY. 23oxidised. The readiness and completeness with which cuprons oxideabsorbs oxygen when moderately heated may be used as a means ofobtaining a very perfect vacuum.Some Reactions of Chrornyl Dichloride. By QUANTIN (Compt.rend., 99, 707-7'09) .--Chromic chloride, Cr,CI,, can be prepared bypassing a mixture of chlorine and carbonic oxide over chromiumsesquioxide, heated to redness ; and is readily obtained in violet crys-tals by passing vapour of chromyl dichloride, chlorine, and carbonicoxide through a glass tube heated a t 500-600" ; 'LCrO,Cl, + 4CO +Cl, = 4c02 + CrzC16. I n this reaction, the chromyl dichloride is notfirst reduced to chromous chloride by the carbonic oxide, for if a mix-ture of chromyl dichloride with carbonic oxide alone is passed throughthe hot tube, vivid combustion takes place with formation of greenchromium sesquioxide and violet chromic chloride.The progress ofthe first reaction may be represented by the following equations :-C. H. B.(1) CO + 2CrO2Cl2 = Cr,O, + CO, + 2C1,( 2 ) Cr,O, + 3CO + 3C1, = Cr,C16 + 3c0,.The carbonic oxide combines only with the oxygen which wouldhave been liberated by the action of heat alone, and does not reducethe sesquioxide which is formed, but the latter is convei-ted intochromyl dichloride by the action of the chlorine which is liberatedand the excess of carbonic oxide. The same results are obtained withany mixture which will give off chromyl dichloride. Dry hydro-chloric acid gas acts slightly on chromyl dichloride a t a red heat, acertain quantity of chlorine, water-vapour, and black chromium oxidebeing formed, but no violet oxychloride is produced.When chromyldichloride is decomposed by heat, the only products are chlorine,oxygen, and black chromium oxide. C. H. B.Chromamrnonium Compounds. Luteochromium Salts. ByS. M. J~RGEKSEN (J.ppr. Chem., 30,1--32).--In a former communication(this Journal, Abstr., 1882, 1167), the author pointed out that a solu-tion of chromammonium chloride i n ammonic chloride undergoesoxidation in absence of air, heat is produced and hydrogen evolved,and the chief product is the roseo-chloride. If the mixture is cooledand the oxidation takes place slowly, then luteochrornium chloride isthe chief product. To prepare this compound, a solution of chromouschloride, prepared by Christenskn's method, is forced by hydrogenpressure into a vessel containing a mixture of 700 grams of ammoniumchloride and 750 C.C.solution of ammonia (sp. gr. 0.91). The vessel,entirely filled with this mixture, is closed by a stopper, through whichpasses a delivery tube opening under water. The vessel is surroundedby cold water to moderate the reaction. The evolution of hydrogentakes place slowly and ceases in about 94 hours, the undissolvedammonium chloride is covered with the lutcocbromium chloride, a.portion of which is also contained in the solution, from which it, maybe obtained by precipitation with alcohol ; the precipitate after beingwashed with alcohol is dried, dissolved in warm water, and the FO~U-t i v i i filtered into nitric acid (sp.gr. 1.39) ; in this manner a precipitat24 ABSTHACTS OF CHEMICAL PAPERS.of luteochromium nitrate is obtained. The nitrate is washed withdilute nitric acid (1 vol. of nitric acid to 2 vols. of water), and theacid removed by washing with dilute alcohol.The luteochromium chloride mixed with the ammonium chloride isseparated by repeated treatment with water, the aqueous extracts areprecipitated by nitric acid, and thus further quantities of luteochro-mium nitrate are obtained.Blomstrand’s method of preparing luteocobalt salts may be appliedfor the preparation of luteochromium salts.L?cteoch.romium nitrate, Cr212NH3,6N03, is obtained from dilutesolutions on addition of concentrated nitric acid in long narrowprisms ; from concentrated solutions, dilute nitric acid precipitates itin orange-yellow, lnstrous, quadratic tables. It may be crystallisedfrom wclrm water containing nitric acid, and then forms small quad-ratic pyramids.Luteochroiriium ititrate sulphate, CrJ 2NH3,2NO,.2SO4, obtained byadding dilute sulphnric acid to a solution of the nitrate, or by addi-tion of ammonium sulphate and ammonia, forms yellow, lustrous,quadratic octahedra.L~iteoehromium nitrate ylatinochloride, Cr212NH3,2NO,,2PtCl6 +2H20, an orange-yello w crystalline precipitate, formed when hydrogenplatinochloride is added to a solution of the luteo-nitrate.Luteochromizcm chloride, cr212NH3,cl6 + 2H,O, is best obtained byfirst treating a, saturated solution of the nitrate with concentratedhydrochloric acid and mercuric chloride, a yellow precipitate of thecompound Cr212NH3,C1,,2HgC1, is obtained. This mercury conipoundsuspended in water, and decomposed by sulphuretted hydrogen, givesa solution from which, on evaporation, the luteochromium chlorideseparates in large yellow crystals.It is converted by concentratedhydrochloric acid into the chloropurpureo-chloride.Luteochromaum platinoclilorides ; three such compounds have beenobtained : ( a ) Cr,12NH3,3PtC1, + 6H20 is formed as .an orange-yellow crystalline precipitate when sodium platinochloride is added toa dilute solution of the neutral luteo-chloride ; (6) Cr,12NH3C12,2PtCl~ + 5H,O is produced when an acid solution of the luteo-chloride isprecipitated by a solution of platinic chloride ; it forms long orange-yellow needles ; by cold water, it is resolved into luteo-chloride and thesalt G.When the salt ( b ) is washed with dilute hylrochloric acid, itis converted into the componnd Cr2l2NH3C1,,PtC~, + 2H20.lhteochromium bromide, Cr,12NH3,Br6, prepared by the action ofhydrobromic acid on a half-saturated solution of the nitrate ; i t formsan orange-yellow crystalljne precipitate, and is less soluble than thechloride.Luteochromium p latinobromide, CrJ 2NH3, 3P tBr6 + 4H20, preparedby adding a dilute solution of sodium platinobromide t o a dilute solu-tion of the luteo-bromide. It forms a precipitate consisting of deepvermillion, lustrous, quadratic, and eight-sided tables.When lessdilute solutions are employed, or the above precipitate is allowed tostand, a change takes place, and a compound similar to the luteo-chromium platinochloride with 6H20 is formed.Luteochrornium iodide, Crz12NH3,T6, is formed by treating a solutioINORGANIC CHEMISTRY. 25of the nitrate with solid potassic iodide: the yellow precipitate iswashed with hydriodic acid, dissolved in water, and filtered intohydriodic acid. It crystallises i n lustrous rhombic tablets, and isisom orphous with the bromide.Luteochrorniurn iodide sulyhate, CrJ2NH3,T2,2 SO4, is formed bytreating an ammoniacal solution of the chloride with ammoniumiodide and ammonium snlphate.L uteocliromium sulphate, Crz12NH,,3SOa + 5H20, is prepared byneutralising luteochromium hydroxide (formed by rubbing togetherthe luteo-bromide and moist silver oxide) with sulphuric acid, and pre-cipitating the solution with alcohol ; it crystallises in long, yellow,lustrous crystals.Luteochromiunz sulphate platinochloride, Cr212NH3,2S01,PtC16, isobtained as an orange-yellow precipitate.Luteochromiurn orthophosphate, Cr212NH3,2POd + 8H20, obtainedby treating a solution of the nitrate with sodium phosphate andammonia, as a yellow precipitate consisting of yellow shining needle-shaped crystals.Luteochronzium oxdate, Cr212NH3,3C20r + 4H20, obt'ained as acrystalline precipitate by decomposing the nitrate with ammoniumo xalat e .T'he following salts have been prepared in a simiiar manner : thepyrophosphate, Cr212NH3,2 (P207Na) + 23H20 ; the ferricyanide,It crystallises in octahedra.Crz12NH3,FezCy12 ;the cobalticyanide, Cr212NH,CozCy12 ; and the chromicyanide,Cr212NH3,Cr2Cylz.P. P. I).Double Tungstates of Rare Metals. By HOGBOM (BUZZ. XOC.Chim., 42,2--6).-By methods of fusion, a large number of compoundsof sodium tungstate with the metals of the rare earths were obtained ;these crystallised in the same form as the simple tungstntes describedby Cossa. The salts may be prepared by dissolving the oxides withtungstic acid, in fused sodium tungstate, or in fused sodium chloride,or still better in a fused mixture of the two. The mixture is liquefiedat a bright red heat, and maintained in a semi-liquid condition a t lowredness.Microscopic crystals of the salts are formed and separatedby treating the product with water, in which they are insoluble.Weak acids attack them orily slowly in the cold, but they are com-pletely decomposed by repeated treatment, in a finely powdered condi-tion, wiDh concentrated hydrochloric acid. It was in this way thatthe analyses of the greater number were made ; the others were fusedwith a mixture of alkaline carbonates, and the tungstic acid precipi-tated by mercuric nitrate. Notwithstanding the difference in compo-sition, the salts bear it great resemblance to one another in crystallineform, which is generally that of a tet(ragona1 octahedron. Thesewere not obtained large enough to measure the angles exactly, but anapproximate measurement was made with the aid of the microscope.The salts described may be arranged under the following types :2G ABSTRACTS OF CBEMICAL PAPERS.I. { 4gr;y} ~wo,; R = La, Ce, or G.11. { 'g:,:} 6W03; R = Di.IV. { grh:} 4W0, ; R = Di.V. { 'FG;} 4W0,;. R = Th.The salts of the types I, 11, and V are formed in presence of excessof sodium tunstate, and those of t4he types 111 and IV in presence ofexcess of sodium chloride. I n a note appended to this paper, Clevecomments on the remarkable fact of t,he similarity in crystallineform of t,hese different salts, all of which either crystallise i n the Eameform or in that of scheelite, which is isomorphous with fergusonite.Other cases of apparently anomalous isomorphism occnr with the rareearths and oxides of the formula RO. Thus titanite is isomorphouswith yttrotitanite, and according to Nordenskiold, cerite, 2CZO3,3SiO2,with peridote, 2Mg0,Si02. It) would thus appear that' isomorphism ispossible between compounds of the rare earths and of the oxides ofthe form RO when the total proportion of oxygen is the same in thebasic and acid oxides which const'itute the compounds. The formula?of the metallic oxides of the cerium and yttrium groups have beenso firmly established in other ways, that it is undesirable to changethem solely on account of the isomorphism of certain of their tung-states with scheelite. W. R. D.The Tempering of Steel. By C. FROMME (Anrt. Phys. Chem.,22, 371--S87).-The changes of density and of hardness in iron orsteel heated, and either slowly cooled or suddenly quenched in water,are the subjects investigated in the author's experiments. I n temperedsteel the density and hardness by 110 means go together, for increaseddensit'y more often corresponds with diminished hardness and aicevers&. The results recorded in the paper support the theory that intempering there takes place not only the mechanical and purelyphysical process of sudden contraction, but also another process of achemical nature consistino; chiefly in the combination of the ironwith the free carbon distributed through its mass. R. R