INORGAVLC CHEJIISTRY, 15 I n o r g a n i c C h e mi s t r y. Source of Hydrogen Occluded by Zinc-dust. By G . WILLIAMS (Chem. News, 52, 205--207).-1n continuation of the experiments on the occlusion of hydrogen by zinc-dust (comp. Abstr., 1885, 369, 634), i t is now shown that when 6.749 grams (1 c.c.) of commercial zinc-dust was exposed for a long time in a hard glass retort t.0 the greatest heat of a Bunsen burner, it yielded as much as 47.4 C.C. of hjdro- gen. When the zinc-dust was moistened with boiling water and dried at loo", its weight increased by about 0.1742 gram OIL 6.479 grams, and on heating 6.479 grams of this dried dust in the manner described above, 89.4 C.C. of hydrogen were obtained ; whilst zinc-dust, which had been exposed in a moist atmosphere until it ceased to gain in weight, then dried arid heahed as in the other experiments, gave as much as 362.8 C.C.of hydrogen per 6.479 grams of zinc-dust. Hence zinc-dust t'akes up water and decomposes it, and gives up its hydrogen on heating ; in another experiment it was proved that zinc-dust absorbs hydrogen (9 C.C. per 6.479 grams) a t ordinary temperatures, when surrounded by i t in a moist condition. The author's previous conclusions (Zoc. cit.), therefore, are confirmed. D. A. L.16 ABSTRACTS OF' CHEMICAL PAPERS. Genesis of Sulphur Crystals in Square Tables. Bg C. BRAME ( Compt. rend., 101, 639-642) .-A description of peculiar crystals obtained by condensing sulphur vapour on glass plates. Iodide of Nitrogen. Ry F. RASCHTG (AnnuZen, 230, 212-221). -The author accounts for the discordant results of the analyses of iodide of nitrogen by Gladstone (this Journal, 1851,34), Stahlschmidt, (Pogg.Ann., 119, 421), and Bunsen (Annulen, 84, 1) by the fact that the precipitate obtained by adding ammonia to a sollition of iodine, is decomposed by washing with water. Sesqui-iod amine, NH,,NI, or NH,I,NHI,, is first precipitated, but it is converted during the process of washing into NHT, and NI,. The latter compound dissolves in potassium cyanide, forming cyanoqen iodide :-NT, + 3KCN + 3HzO = 3CNI + NH, + 3KOH. The iodide of nitrogen prepared from a solution of iodine differs in its properties from the io'dide obtained by the action of ammonia on finely divided iodine. The latter compound is much more explosive t'han khe former, as it is capable of exploding when moist.The composition of this substance has not yet been ascertained. w. c. w. Behaviour of Carbonic Anhydride towards Hydrogen at a, High Temperature. By A. NAUMANN arid C. PTSTOR (Bey., 18, 27'24-2727 ; comp. this vol., p. 1036).-Hydrogen has no reducing action on carbonic anhydride at 900". Reactions with Carbonic Anhydride, Carbon Bisulphide, and Sulphurous Anhydride. By A. EILOART (Chem. News, 52, 183--184).-When a mixture of carbonic anhydride and carbon bisul- phide vapour is passed over copper heated to redness, almost pure carbonic oxide is abundantly evolved with simultaneous formation of copper snlphide, Cu2S. Carbon bisulphide alone is decomposed when passed over copper heated below redness, and if copper, coated with carbon from the decomposition of carbon bisulphide, is heated in a stream of carbonic anhydride, only a limited and small quantity of carbonic oxide is slowly produced. Hence the mixture of gases is necessary for the above reaction, and decomposition and combination evidently go on a t the same time.Without copper the mixture of gas is not decomposed in this manner, for instance, when passed over heated pumice. Sulphurous anhydride and carbon bisulphide, when passed over copper or pumice heated even below redness, give rise to cbarbonic anhydride, and as a secondary product carbonic oxide. When sulphurous anhydride is passed over strongly heated carbon, freed as far as possible from air and hydrogen, sulphur is deposited and carbonic anhydride formed. D.A. L. Absorbents for Carbon Bisulphide Vapour. By A. EILOART (Chem. News, 52, 184).-To test the efficiency of various absorbents €or carbon bisdphide vapour, air saturated with this vapour was passed through certain substances, a t the rate of 1 litre per hour. Caoutcliin, powdered roll sulphur, bromine dissolved i n pot'assium bromide, and linseed oil are imperfect absorbents, iodine and potassiumINORGANIC CHEMISTRY. 17 tri-iodide absorb completely a large proportion of carbon bisulphide vapour, but soon get saturated. When these substances are used, a guard tube (filled with paraffin) must be attached to arrest iodine yapour. The carbon bisulphide can be removed from the saturated iodine solution by simple exposure to the air. Large quantities of gas cannot be conveniently treated in this manner.For analytical purposes, the volume of gas t o be analysed is treated with linseed oil in a Crum's tube ; used in this way, linseed oil is the best, as it absorbs the carbon Eisulphide immediately without dissolving the carbonic anhydride. Artificial Formation of Twin Crystals of Potassium Sulphate and Chromate by Increase of Temperahme. By H. BAUMHAUER (Zeit. Kryst. dlin., 10, 405).-The observation made by Mallard, that in twin crystals of potassium sulphate new twin-lamelle are formed by heating, is confirmed by the author. Perfectly simple crystals (:an, by heating, be converted into complicated twin crystals. In the same way, plates of potassium chromate, cut parallel to the basal plane, after slight heating, exhibit a great number of twin lamellae.B. H. B. Action of Sodium Thiosulphate on Metallic Salts. By P. JOCHUM (Chem. Centr., 16, 642-644) .-By treating solutions of sul- phate or chloride or acetate of copper, lead, cadmium, silver, gold, platinum, zinc, manganese, cobalt, or nickel, with solution of sodium t hiosulphate, the author has obtained a series of double thiosulphates, of which an account is given in this paper. D. A. L. P. P. B. Action of Carbonic Oxide on Lead and Silver Chlorides. By A. G. BLOXAM (Chem. News, 52, 183).--Contrary to the statement of Gobel ( J . pr. Chem., 6,388), who describes a method of preparing carbonyl chloride founded on the supposed reaation between carbonic oxide and these chlorides, the author finds that neither lead nor silver chloride is attacked by heating in a current of dry carbonic oxide.When heated in a current of moist nitrogen, lead chloride loses weight with evolution of hydrogen chloride. Alteration of Mercurous Iodide by Exposure to Light. By - YVON (J. Pharm. [ S ] , 11, 148-149) .-Crystallised mercurous iodide, exposed to the light for eight years, in a flask closed by a sheet of paper, had become almost black. Analysis shows the altered iodide to contain 60.72 per cent. of mercury, instead of 61.16 per cent. Chromic Phosphate. By C. L. BLOXAM (Chem. News, 52, 194- 195) .-The precipitate produced by boiling solutions of chromic salts with sodium phosphate and acetic acid has been found by the author t o consist of normal chromic phosphate, mixed with slight excess of chromic oxide, Crz03, and retaining about 5 mols.H,O a t 100". D. A. L. D. A. L. J. T . Molybdenum-derivatives. By C. BARKALD (Chenz. Cerbtr., 1885, 424-425).-Some time ago, Werther showed ( J . pr. C72em., 83, 198) that hydrogen peroxide caused a jellow coloration in acid solutions of VOL. L. C18 ABSTRACTS OF CHEMICAL PAPERS. molybdic acid. The same reaction takes place with the oxides, sul- phides, and salts of molybdenum, but after a, time gas is evolved, and the colour disappears. The reaction forms a good test for molybdenum, and serves to detect it in the presence of chromates, as the blue coloration caused by hydrogen peroxide with chromates may be ex- tracted by agitation with ether, whilst the yellow molybdic coloration remains in the aqueous liquid. The test is, however, much less delicate with molydic compounds than with chromates, and is quite masked by the presence of vanadium or titanium compounds.The normal molybdates and polymolybdates when added to hy- drogen peroxide CRU~F: a brown coloration and strong evolution of oxygen. But when commercial ammonium molybdate, Am6Mo,O2( + H20, or analogous salts (for instance, Rammelsberg's seven-thirds salts) are employed, scarcely any evolution of gas takes place, and the deep yellow solutions yield crystalline lemon-yellow compounds by spontaneous evaporation. The ammonia compound, 18Mo03,14NH3,8HZ02 + 18H20, crystallises in lemon-yellow prisms which do not change on ex. posure to the air. Acids deepen the yellow colour of the solution, alkalis discharge it. If zinc is added to the acidified solution, becoxes darker and finally green.Potassium ferrocyanide and thio- cpanate give the .same reactions as with ordinary molybdates ; lead nitrate gives a white precipitate, soluble in nitric acid, insoluble in, b u t becoming dark-coloured by ammonia. Silver and mercurous nitrites both give white precipitates ; barium chloride, a white compound, 19M00,,8Ba0,2H202 + 13H20 ; ferrons sulphate, a dark yellow voluminous precipitate. Silver nitrate gives a pale yellow amorphous precipitate, 32MoOj,13Agz0,2H202. Ferric sulphate yields an amorphous lemon-coloured powder, Fe,03,6Mo03, 16H,O. When fused with molybdic acid the ammonia compound yields a violet-blue powder of the formula Mo,O,. The crystals of the ammonia compound are highly refractive, and have a sp.gr. of 2 * 9 i 5 ; the sp. gr. of their solution saturated a t 17.4" is 1.486. The analogous potassium molybdate, K6M07024 + 4HL0, yields, with the peroxide, the derivative 16hf0~O,6K,0,4H,0~ + 13H,O ; no corresponding sodium salt could be obtained. The author has also made experiments on the use of the electmlytic method for the quantitative estimation of molybdenum, but finds the results unsatisfactory. L. T. T. Vanadic Anbydride. By A. DITTE (Cf371Zpt. rend., 101, 698-702). -When ammonium vanadate is heated in a closed crucible out of contact with air, the vanadic acid is reduced by the evolved gases, and yields a dark coloured mixture of the two oxides, VZ04 and V,OB, in which the latter predominates. If this product is oxidised with nitric acid, the solution evaporated to dryness, and the residue gently heated, pure vanadic anhydride is left in the form of a reddish-yellow ochreous powder. When this powder is exposed to the air, i t absorbs water and becomes red, forming first the hydrate V205,H20, and after- warcis the hydrate V2O5;2HI1O, The latter compouud, if placed in anINORGANIC CHEMISTRY.19 atmosphere saturated with aqueous vapour, absorbs more water and forms the hydrate V,05,8H,0, but this loses 6 mols. H,O when ex- posed to the air. The amount of water absorbed by the vanadic anhgdride depends on the tension of the aqueous oapour in the sur- rounding atmosphere. When the anhydride or one of the red hydrates is brought in contact with a small quantity of water, it instantly forms a viscous, almost gelatinous mass, which dissolves completely on adding more water, forming a deep blood-red, limpid solution.No precipitate is formed when this solution is boiled, or i f it is mixed with alcohol in the cold, but the addition of a small quantity of nitric acid produces a flocculent reddish precipitate soluble in excess of acid with production of a straw-coloured solution. If this solution is evaporated in a vacuum over potash, it leaves a reddish, velvety mass of hydrated vanadic acid, readily soluble in water with production of the original blood-red solution. If the blood-red solution is mixed with excess of potassium chloride, the whole of the vanadic anhydride is precipitated in reddish flocks, which are not altered by boiling, and are insoluble in water coutaining potassium chloride, but dissolve slightly in pure water, forming a yellow solution, whilst the precipitate, which settles very slowl~, becomes orange coloured.When a cold solution of ammonium vanadate is mixed with a small quantity of nitric acid, a reddish turbidity is produced, which dis- appears on adding more acid, but if the solution is boiled, the greater part of the vanadium is precipitated. This precipitat'e, after washing, and drying by exposure to air, has the composition V205,2H20, but differs from the hydrate described above, in that it does not alter in contact with water, and is only very slightly soluble even at 100". If the product of the calcination of ammonium vanadate is heated in a current of dry air a t 440" for several hours, it is converted into a pale yellow vanadic anhydride with a slight greenish tinge. This variety corresponds with the slightly soluble hydrates, and can also be obtained by heating these hydrates a t 350-440", but is then red- dish-yellow. It does not absorb moisture from the air, and dissolves only very slightly in water, forming a yellow solution.When ammonium vanadate is heated in contact with the air until the residue fuses, the product is not pure vanadic anhydride, hut contains a compound of this oxide with the lower oxide, V,O,. If, however, the product obtained by the action of nitric acid on the mixed oxides formed by heating amnionium vanadate in a closed vessel, is heated to fusion and allowed to cool, it solidifies in dark brownish-red needles, which have a greasy lustre and are transparent in thin plates.This variety of the anhydride does not form a hydrate even if left in contact with water f o r several months, and a saturated solution of it contains only 0.05 gram per litre. From these observations, it follows that vanadic anhydride exists in three distinct modifications, which may be regarded as analogous to the polymeric varieties of phosphoric anhydride, described by Haute- feuille and Perrey. C. H. B. c 220 ABSTRACTS OF CHEMICAL PAPERS. Action of Hydrogen Peroxide on Antimony Sulphides. Bp F. RASCHIG (Rer., 18, 2743 - 2745).-When freshly precipitated antimony sulphide, from 30 grams of tartar emetic, is treated with 500 C.C. of concentrated ammonia, and 900 C.C. of a 2+ per cent.solution of hydrogen peroxide, about is converted into antimonic acid which forms a flaky precipitate. The solution contains am- monium sulphate and antimoniate ; the latter salt is precipitated by the addition of alcohol, and when dried at the ordinary tetnperature, has the composition NH4SbOs + 3H20, and is therefore identical with Frbmy’s hydrogen ammonium metantimoniate, H,(NH,),Sb,O, + 5H,O. The reaction above described is fresh evidence of the non-existence of an antimonic acid corresponding v i t h orthophosphoric acid. N. H. M. Equilibrium in the Reaction of Hydrochloric Acid on Antimony Trisulphide, and of Hydrogen Sulphide on a Solution of Antimony Trichloride. By J. LANG (Ber.? 18, 2714- 2724) .-Experiments made by the author confirm the result obtained by De Clermont and Frommel (Abstr., 1879, 13), that water de- composes antimony trisulphide ; the decomposition continues as long as water is present.Hydrochloric acid of all degrees of strength acts on antimony sul- phide. In presence of an excess of the sulphide, the action continues until the strength of the hydrochloric acid diminishes to a certain point, this point depending on the amount of hydrogen sulphide present iu the solution. The equilibrium will then be disturbed if the pressure on the hydrogen sulphide over the solubion be increased ; this causes a reversal of the reaction which is shown by the separation of antimony sulphide. On the other hand, if the hydrogen sulphide be removed from the solution as it is formed, the action of the hydro- chloric acid will continue until ail the antimony sulphide is dis- solved.N. H. M.INORGAVLC CHEJIISTRY, 15I n o r g a n i c C h e mi s t r y.Source of Hydrogen Occluded by Zinc-dust. By G . WILLIAMS(Chem. News, 52, 205--207).-1n continuation of the experimentson the occlusion of hydrogen by zinc-dust (comp. Abstr., 1885, 369,634), i t is now shown that when 6.749 grams (1 c.c.) of commercialzinc-dust was exposed for a long time in a hard glass retort t.0 thegreatest heat of a Bunsen burner, it yielded as much as 47.4 C.C. of hjdro-gen. When the zinc-dust was moistened with boiling water and driedat loo", its weight increased by about 0.1742 gram OIL 6.479 grams, andon heating 6.479 grams of this dried dust in the manner describedabove, 89.4 C.C.of hydrogen were obtained ; whilst zinc-dust, whichhad been exposed in a moist atmosphere until it ceased to gain inweight, then dried arid heahed as in the other experiments, gave asmuch as 362.8 C.C. of hydrogen per 6.479 grams of zinc-dust. Hencezinc-dust t'akes up water and decomposes it, and gives up its hydrogenon heating ; in another experiment it was proved that zinc-dust absorbshydrogen (9 C.C. per 6.479 grams) a t ordinary temperatures, whensurrounded by i t in a moist condition. The author's previousconclusions (Zoc. cit.), therefore, are confirmed. D. A. L16 ABSTRACTS OF' CHEMICAL PAPERS.Genesis of Sulphur Crystals in Square Tables. Bg C. BRAME( Compt. rend., 101, 639-642) .-A description of peculiar crystalsobtained by condensing sulphur vapour on glass plates.Iodide of Nitrogen. Ry F.RASCHTG (AnnuZen, 230, 212-221).-The author accounts for the discordant results of the analyses ofiodide of nitrogen by Gladstone (this Journal, 1851,34), Stahlschmidt,(Pogg. Ann., 119, 421), and Bunsen (Annulen, 84, 1) by the fact thatthe precipitate obtained by adding ammonia to a sollition of iodine,is decomposed by washing with water. Sesqui-iod amine, NH,,NI,or NH,I,NHI,, is first precipitated, but it is converted duringthe process of washing into NHT, and NI,. The latter compounddissolves in potassium cyanide, forming cyanoqen iodide :-NT, +3KCN + 3HzO = 3CNI + NH, + 3KOH. The iodide of nitrogenprepared from a solution of iodine differs in its properties from theio'dide obtained by the action of ammonia on finely divided iodine.The latter compound is much more explosive t'han khe former, as it iscapable of exploding when moist.The composition of this substancehas not yet been ascertained. w. c. w.Behaviour of Carbonic Anhydride towards Hydrogen at a,High Temperature. By A. NAUMANN arid C. PTSTOR (Bey., 18,27'24-2727 ; comp. this vol., p. 1036).-Hydrogen has no reducingaction on carbonic anhydride at 900".Reactions with Carbonic Anhydride, Carbon Bisulphide,and Sulphurous Anhydride. By A. EILOART (Chem. News, 52,183--184).-When a mixture of carbonic anhydride and carbon bisul-phide vapour is passed over copper heated to redness, almost purecarbonic oxide is abundantly evolved with simultaneous formation ofcopper snlphide, Cu2S.Carbon bisulphide alone is decomposedwhen passed over copper heated below redness, and if copper, coatedwith carbon from the decomposition of carbon bisulphide, is heated ina stream of carbonic anhydride, only a limited and small quantity ofcarbonic oxide is slowly produced. Hence the mixture of gases isnecessary for the above reaction, and decomposition and combinationevidently go on a t the same time. Without copper the mixture ofgas is not decomposed in this manner, for instance, when passed overheated pumice. Sulphurous anhydride and carbon bisulphide, whenpassed over copper or pumice heated even below redness, give rise tocbarbonic anhydride, and as a secondary product carbonic oxide.When sulphurous anhydride is passed over strongly heated carbon,freed as far as possible from air and hydrogen, sulphur is depositedand carbonic anhydride formed.D. A. L.Absorbents for Carbon Bisulphide Vapour. By A. EILOART(Chem. News, 52, 184).-To test the efficiency of various absorbents€or carbon bisdphide vapour, air saturated with this vapour waspassed through certain substances, a t the rate of 1 litre per hour.Caoutcliin, powdered roll sulphur, bromine dissolved i n pot'assiumbromide, and linseed oil are imperfect absorbents, iodine and potassiuINORGANIC CHEMISTRY. 17tri-iodide absorb completely a large proportion of carbon bisulphidevapour, but soon get saturated. When these substances are used, aguard tube (filled with paraffin) must be attached to arrest iodineyapour. The carbon bisulphide can be removed from the saturatediodine solution by simple exposure to the air.Large quantities of gascannot be conveniently treated in this manner. For analytical purposes,the volume of gas t o be analysed is treated with linseed oil in a Crum'stube ; used in this way, linseed oil is the best, as it absorbs the carbonEisulphide immediately without dissolving the carbonic anhydride.Artificial Formation of Twin Crystals of Potassium Sulphateand Chromate by Increase of Temperahme. By H. BAUMHAUER(Zeit. Kryst. dlin., 10, 405).-The observation made by Mallard, thatin twin crystals of potassium sulphate new twin-lamelle are formedby heating, is confirmed by the author. Perfectly simple crystals(:an, by heating, be converted into complicated twin crystals.In thesame way, plates of potassium chromate, cut parallel to the basalplane, after slight heating, exhibit a great number of twin lamellae.B. H. B.Action of Sodium Thiosulphate on Metallic Salts. By P.JOCHUM (Chem. Centr., 16, 642-644) .-By treating solutions of sul-phate or chloride or acetate of copper, lead, cadmium, silver, gold,platinum, zinc, manganese, cobalt, or nickel, with solution of sodiumt hiosulphate, the author has obtained a series of double thiosulphates,of which an account is given in this paper.D. A. L.P. P. B.Action of Carbonic Oxide on Lead and Silver Chlorides. ByA. G. BLOXAM (Chem. News, 52, 183).--Contrary to the statementof Gobel ( J . pr. Chem., 6,388), who describes a method of preparingcarbonyl chloride founded on the supposed reaation between carbonicoxide and these chlorides, the author finds that neither lead nor silverchloride is attacked by heating in a current of dry carbonic oxide.When heated in a current of moist nitrogen, lead chloride losesweight with evolution of hydrogen chloride.Alteration of Mercurous Iodide by Exposure to Light.By - YVON (J. Pharm. [ S ] , 11, 148-149) .-Crystallised mercurousiodide, exposed to the light for eight years, in a flask closed by asheet of paper, had become almost black. Analysis shows the alterediodide to contain 60.72 per cent. of mercury, instead of 61.16 per cent.Chromic Phosphate. By C. L. BLOXAM (Chem. News, 52, 194-195) .-The precipitate produced by boiling solutions of chromicsalts with sodium phosphate and acetic acid has been found by theauthor t o consist of normal chromic phosphate, mixed with slightexcess of chromic oxide, Crz03, and retaining about 5 mols.H,O a t100". D. A. L.D. A. L.J. T .Molybdenum-derivatives. By C. BARKALD (Chenz. Cerbtr., 1885,424-425).-Some time ago, Werther showed ( J . pr. C72em., 83, 198)that hydrogen peroxide caused a jellow coloration in acid solutions ofVOL. L. 18 ABSTRACTS OF CHEMICAL PAPERS.molybdic acid. The same reaction takes place with the oxides, sul-phides, and salts of molybdenum, but after a, time gas is evolved, andthe colour disappears. The reaction forms a good test for molybdenum,and serves to detect it in the presence of chromates, as the bluecoloration caused by hydrogen peroxide with chromates may be ex-tracted by agitation with ether, whilst the yellow molybdic colorationremains in the aqueous liquid. The test is, however, much lessdelicate with molydic compounds than with chromates, and is quitemasked by the presence of vanadium or titanium compounds.The normal molybdates and polymolybdates when added to hy-drogen peroxide CRU~F: a brown coloration and strong evolution ofoxygen.But when commercial ammonium molybdate, Am6Mo,O2( +H20, or analogous salts (for instance, Rammelsberg's seven-thirdssalts) are employed, scarcely any evolution of gas takes place, and thedeep yellow solutions yield crystalline lemon-yellow compounds byspontaneous evaporation.The ammonia compound,18Mo03,14NH3,8HZ02 + 18H20,crystallises in lemon-yellow prisms which do not change on ex.posure to the air. Acids deepen the yellow colour of the solution,alkalis discharge it. If zinc is added to the acidified solution,becoxes darker and finally green. Potassium ferrocyanide and thio-cpanate give the .same reactions as with ordinary molybdates ; leadnitrate gives a white precipitate, soluble in nitric acid, insoluble in,b u t becoming dark-coloured by ammonia. Silver and mercurousnitrites both give white precipitates ; barium chloride, a whitecompound, 19M00,,8Ba0,2H202 + 13H20 ; ferrons sulphate, a darkyellow voluminous precipitate. Silver nitrate gives a pale yellowamorphous precipitate, 32MoOj,13Agz0,2H202.Ferric sulphate yieldsan amorphous lemon-coloured powder, Fe,03,6Mo03, 16H,O. Whenfused with molybdic acid the ammonia compound yields a violet-bluepowder of the formula Mo,O,. The crystals of the ammonia compoundare highly refractive, and have a sp. gr. of 2 * 9 i 5 ; the sp. gr. oftheir solution saturated a t 17.4" is 1.486.The analogous potassium molybdate, K6M07024 + 4HL0, yields,with the peroxide, the derivative 16hf0~O,6K,0,4H,0~ + 13H,O ; nocorresponding sodium salt could be obtained.The author has also made experiments on the use of the electmlyticmethod for the quantitative estimation of molybdenum, but finds theresults unsatisfactory. L. T. T.Vanadic Anbydride. By A. DITTE (Cf371Zpt. rend., 101, 698-702).-When ammonium vanadate is heated in a closed crucible out ofcontact with air, the vanadic acid is reduced by the evolved gases,and yields a dark coloured mixture of the two oxides, VZ04 and V,OB,in which the latter predominates.If this product is oxidised withnitric acid, the solution evaporated to dryness, and the residue gentlyheated, pure vanadic anhydride is left in the form of a reddish-yellowochreous powder. When this powder is exposed to the air, i t absorbswater and becomes red, forming first the hydrate V205,H20, and after-warcis the hydrate V2O5;2HI1O, The latter compouud, if placed in aINORGANIC CHEMISTRY. 19atmosphere saturated with aqueous vapour, absorbs more water andforms the hydrate V,05,8H,0, but this loses 6 mols. H,O when ex-posed to the air.The amount of water absorbed by the vanadicanhgdride depends on the tension of the aqueous oapour in the sur-rounding atmosphere. When the anhydride or one of the red hydratesis brought in contact with a small quantity of water, it instantlyforms a viscous, almost gelatinous mass, which dissolves completelyon adding more water, forming a deep blood-red, limpid solution.No precipitate is formed when this solution is boiled, or i f it is mixedwith alcohol in the cold, but the addition of a small quantity of nitricacid produces a flocculent reddish precipitate soluble in excess ofacid with production of a straw-coloured solution. If this solution isevaporated in a vacuum over potash, it leaves a reddish, velvety massof hydrated vanadic acid, readily soluble in water with production ofthe original blood-red solution.If the blood-red solution is mixed with excess of potassium chloride,the whole of the vanadic anhydride is precipitated in reddish flocks,which are not altered by boiling, and are insoluble in water coutainingpotassium chloride, but dissolve slightly in pure water, forming ayellow solution, whilst the precipitate, which settles very slowl~,becomes orange coloured.When a cold solution of ammonium vanadate is mixed with a smallquantity of nitric acid, a reddish turbidity is produced, which dis-appears on adding more acid, but if the solution is boiled, the greaterpart of the vanadium is precipitated. This precipitat'e, after washing,and drying by exposure to air, has the composition V205,2H20, butdiffers from the hydrate described above, in that it does not alter incontact with water, and is only very slightly soluble even at 100".If the product of the calcination of ammonium vanadate is heatedin a current of dry air a t 440" for several hours, it is converted intoa pale yellow vanadic anhydride with a slight greenish tinge.Thisvariety corresponds with the slightly soluble hydrates, and can alsobe obtained by heating these hydrates a t 350-440", but is then red-dish-yellow. It does not absorb moisture from the air, and dissolvesonly very slightly in water, forming a yellow solution.When ammonium vanadate is heated in contact with the air untilthe residue fuses, the product is not pure vanadic anhydride, hutcontains a compound of this oxide with the lower oxide, V,O,.If,however, the product obtained by the action of nitric acid on themixed oxides formed by heating amnionium vanadate in a closedvessel, is heated to fusion and allowed to cool, it solidifies in darkbrownish-red needles, which have a greasy lustre and are transparentin thin plates. This variety of the anhydride does not form ahydrate even if left in contact with water f o r several months, and asaturated solution of it contains only 0.05 gram per litre.From these observations, it follows that vanadic anhydride exists inthree distinct modifications, which may be regarded as analogous tothe polymeric varieties of phosphoric anhydride, described by Haute-feuille and Perrey. C.H. B.c 20 ABSTRACTS OF CHEMICAL PAPERS.Action of Hydrogen Peroxide on Antimony Sulphides. BpF. RASCHIG (Rer., 18, 2743 - 2745).-When freshly precipitatedantimony sulphide, from 30 grams of tartar emetic, is treated with500 C.C. of concentrated ammonia, and 900 C.C. of a 2+ per cent.solution of hydrogen peroxide, about is converted into antimonicacid which forms a flaky precipitate. The solution contains am-monium sulphate and antimoniate ; the latter salt is precipitated bythe addition of alcohol, and when dried at the ordinary tetnperature,has the composition NH4SbOs + 3H20, and is therefore identical withFrbmy’s hydrogen ammonium metantimoniate, H,(NH,),Sb,O, + 5H,O.The reaction above described is fresh evidence of the non-existence ofan antimonic acid corresponding v i t h orthophosphoric acid.N. H. M.Equilibrium in the Reaction of Hydrochloric Acid onAntimony Trisulphide, and of Hydrogen Sulphide on aSolution of Antimony Trichloride. By J. LANG (Ber.? 18, 2714-2724) .-Experiments made by the author confirm the result obtainedby De Clermont and Frommel (Abstr., 1879, 13), that water de-composes antimony trisulphide ; the decomposition continues as longas water is present.Hydrochloric acid of all degrees of strength acts on antimony sul-phide. In presence of an excess of the sulphide, the action continuesuntil the strength of the hydrochloric acid diminishes to a certainpoint, this point depending on the amount of hydrogen sulphidepresent iu the solution. The equilibrium will then be disturbed ifthe pressure on the hydrogen sulphide over the solubion be increased ;this causes a reversal of the reaction which is shown by the separationof antimony sulphide. On the other hand, if the hydrogen sulphidebe removed from the solution as it is formed, the action of the hydro-chloric acid will continue until ail the antimony sulphide is dis-solved. N. H. M