INORGhWICl CHEMISTRY. 1'; I n o r g a n i c C h e m i s t r y . Conversion of Chlorine into Hydrogen Chloride. By RICHARD LoRmz (Zeit. anorg. Cliern., 1895, 10, 74--77).-Chlorine is com- pletely converted into hydrogen chloride by passing it, mixed with steam, through a tube filled with coke, and heated to IL faint red heat. The action is expressed by t h e equation 2Cl + H,O + C = 2HCl + CO, and so comp1et.e is itc that the gases issuing from the hot tube do not contain suEcient chlorine t o give a reaction with potassium iodide and starch. After absorption of t h e hjdrogen chloride by means of water, t h e residual gas is almost pure carbonic oxide, containing only a very sniall qu&tit,y of carbon-ic anbydridc. E. C. R. Crystallisation of Bromine. By HER'RTK ARcrro\$-sKI (Zeit.anorg. Chern., 1895, 10, 25-226).-Bromine crystallises from a very concentrated solution i n carbon bisulpliide at -90" i n slender, car- mine red needles, having a somewhat similar appearance to chromic, anhydride. The cryskals are pure bromine. Bromine, when suffi- ciently cooled, solidifies to a dark brown mass, which has a crjstallinc fracture, but not so well defined a metallic lustre as iodine. E. C . R. VOL. LXX. ii. 318 ABSTRACTS OF CHEMIOAL PAPERS. Compound of Selenium with Arsenic. By A. CLETER and WILEELJI MUTHEIANN (Zeit. aitorg. Chenz., 1895, 10, 117-1 47).-The authors attempted to prepare conipounds of arsenic acid in which the oxygen is partially replaced by selenium. For this purpose, arsenious acid dissolved in concentrated potassium hydroxide was mixed with selenium, also dissolved in potassium hgdroxide. A complic.t,ted reaction takes place, a small quantity of selenium is deposited, but the only compound which the authors were able to isolate was a potassium polyselenide, described below, Potassium nxyselenoarsenate, K6As2Se50s + 10H20, is obtained by treating arsenic pentnselenidc with potassium hydroxide.The arsenic pentaselenide ( 5 grams), prepared by melting a finely ground mixture of arsenic and selenium in a porcelain crucible, is gradually added to a concentrated solution of potassium hydroxide (10 grams), the mixture being cooled with ice; it is then filtered into absolute alcohol (300 c.c), and the orange-red, crystalline mass thus obtained is washed with alcohol and dried on a porous plate.It is andogous to the salt Na,As2S305 + 24H20, described by Geuther. It rapidly decomposes and darkens on exposure to air and moisture, selenium being deposited; i t dissolves easily in water, forming a greenish- yellow solution, and then decomposes rapidly with deposition of red selenium. With salts of the heavy metals it gives dark, amorphous precipitates ; with barium salts, a reddish-white compound, which decomposes very rapidly. When treated with acids, it yields arsenic pent aselenide. Arsenic pentuselenide, As2Se5, prepared by melting its constituents toget her: has propcrt,ies similar to those of Ulsmann’s triselenide. When heated in the air, it decomposes: and red selenium and a greyish- black sublimate are formed. If prepared by decomposing the preceding compound with acid, it forms a reddisb-brown powder.It dissolves t o a greenish-red solution in alkalis and ammonia, and is reprecipi- tated unchanged by acids; it is insoluble in dilute acids and con- centrated hydrochloric acid, and is slowly decomposed by warm, dilute nitric. acid, very rapidly by cold, fuming nitric acid, whereby arsenic and selenious acid are formed. I t is insoluble in water, alcohol, ether, and carbon bisulphide, and has neither taste nor odour. Potassium metaselenoarsenate, KAsSe3 + 2H20, is obtained by adding arsenic pentaselenide to a solution of selenium in potassium hydr- oxide; the mixture, after being heated for some time, is filtered into alcohol, a small quantity of water is added, in order to dissolve other compounds which are formed a t the same time, and the product is then dried on B porous plate.It crystallises in reddish-yellow prisms, and is easily soluble in hot water, but the solution soon decomposes, with deposition of selenium ; alkaline solutions are somewhat more stable. Acids precipitate arsenic pentaselenide from the aqueous sorution with evolution of hydrogen selenide. With lead and silver salts, it gives a black precipitate ; with barium salts, a reddish-white precipitate, which rapidly decomposes. Potassium thioselenoarsennte, K,As,Se,S3 + 12H20, is prepared by adding arsenic pentasulphide to a solution of potassium sulphide,1NORGANIO CEEMISTRY. 19 heating the mixture to boiiing, and filtering the solution into alcohol ; the compound then crystallises out in orange-red needles. It is unstable on exposure to air and moisture, melts to a reddish-yellow liquid at the warmth of the hand, and is fairly stable in aqueous solu- tion ; the aqueous solution, when treated with acids, gives a brownish- red precipitate of the pentaselenide mixed with sulphur, hydrogen sulphide being evolved. Sodium oxyselenoamenate, 3NazSe,3Na20,As20, + 50H20, is ob- tained by warming arsenic pentuselenide with a concentrated soh- tion of sodium hydroxide ; a new hydrate of sodium monoselenide, described below, is at first precipitated, but on filtering, and mixing the filtrate with alcohol, the oxy-compound crystallises out in white, elongated prisms, which are fairly stable on exposure to air.It is easily soluble in water ; acid precipitates selenium from the solution and an arsenic selenide is not formed.With lead and silver salts, it gives a black precipitate ; and with barium chloride, a white, amor- phous precipitate which is easily soluble in warm water. Sodium selenoarsenite, Na,AsSes + 9H20, is formed together with other salts when arsenic pentaselenide is boiled with a solution of selenium in sodium hydroxide ; on concentrating the filtered solution in a vacuum, a mixture of white needles and orange-red tetrahedra is obtained. On separating these by levigation, a small quantity of the tetrahedra are obtained. It8 is unstable on exposure to air, becoming coated with grey selenium; i t is easily soluble in water, and the brown solution when treated with dilute acids gives a brownish-red precipitate with evolution of hydrogen selenide.Sodium thioselenoarsenate, Na6As2Se5S:3 + 18H20, prepared in a similar way to the corresponding potassium salt, crystallises in golden-yellow spangles, or in beautiful, long needles which are fairly stable, bat slowly darken and decompose on exposure to air. It is easily soluble in water; and acids precipitate a brown compound from the dark- brown solution with evoliition of hydrogep sulphide ; towards acids and Ralts of the heavy metals, it behaves like the potassium salt. Potassii~rz triselenide, K2Se3 + 2H20, is obtained, as previously stated, in brown needles, when potassium selenide is mixed with arsenious acid dissolved in alkali ; the crystals rapidly decompose and become coated with grey selenium on exposure to air.It dissolves in water, and the solution when treated with acids, jields selenium and hyclro- gen selenide. Sodium momselenide, Na2Se + 10H20, obtained as medioned above, crystallises in beautiful white needles which rapidly turn red, then brown, and become coated with grey selenium; it is easily soluble in water, but insoluble in alkali hydroxides. It evolves hydrogen selenide on exposure to the air, or when treated with dilute acids ; melts to a brown liquid when warmed, and has the properties assigned to the sodium selenide obtained by Fabre. Helium and Argon. By HEINRICH KAYSER (Cheaz. News, 1895,72, 89).-The author records the discovery of helium in the free state in nature. I n the springs of Wildbad, in the Black Forest, bubbles of gas rise up, which, according to an old analysis of E’ehling, contain E.C. R. 3-220 ABSTRACTS OF CHEMICAL YAPIFRS. 96 per ccnt. of nitrogen. An analysis of this gas showed that after sparking with excess of oxygen aud removal of the residual oxygen with pyrogdlol, a residue was obtained which gave the spectra of argon and helium, Ihe latter being evidedy present i n quantity. Runge and Pasclien found two substances in the gas from clhveite and broggerite, and both these elements appear to be represented in the Wildbad gas. A s a place lias here been found in which the two gases represented by the na.me helinm are liberated and stream into the atmosphere, i t f'ollows that these must be normally present in tlieatmosphere. The author has found this to be tile case, and that argon prepared from the air of Bonn contains helium, the presence of the D, line in the spectrum being most ma~ked.H. C. A Possible Compound of Argon. By WILLIAM Rakisbu (Chenz. News, 1895, 72, 5l).-By making nn arc between two thin carbon rods, in an atmosphere of argon for some four hours, the volume of the gas increased about one-fifth, and was not altered by exposure to water, to caustic soda., or to ammoniacal cuprous chloride. It gave, in addition to a faint argon spectrum, a luminous, finely channelled spectrum, with certain lices nut coincident with argon lines (see Crookes, this vol., ii, 2). D. A. L. Fluorides and Oxyfluorides of Potassium. By G. MARCHETTI (Zeit. unorg. Chem., 1895,10, 66--73).-Anhydrous potassium titano- fluoride, K2TiFb, is prepared by rtdding the theoretical quantity of potassium hydrogen fluoride to a solution of titanium dioxide in an excess of hydrogen fluoride. I t cr3stallises in small, very lustrous leaflets, which are denser than the crystals of the hydrated fluoride, K2TiF,,H,0.I t can be orystallised without change from hot hydro- fluoric acid, but when dissolved in water i t is completely converted into the hydrated salt. Conversely, when t'he hjdrated salt is dis- solved in concentrated hydrotluoric or hydrochloric acid, it is con- T-erted into the anhydrous salt. The normal potassium fluoride compounds of niobium, molybder~nm, and tungsteu, of the formuh Nb02F2,2KF,H20, Mo02F2,2KF,H20, and W02F2,2KF,H20, respectively, behave in the same way. The oxgfluoride of molybdenum, Mo02F2,2KF,H,0, obtained by adding the theoretical quantity of potassium hydroxide to a solutiou of molybdic anhydride in hydrofluoric acid, taking care that t,he mix- ture revmains acid, crystallises from hot hydrofluoric acid in short, lustrous prisms of the composition Mo02Fr,2KF.The salt described by Delafontaine (Arch. Sci. Phys., 1867, 30, 244)) 31002F2,Ki(',H20, is probably a mixture of the two preceding salts, and, according to the author's results may also contain the oxyfluoride MoOFq,KF. The double fluoride OF tungsten, W021?2,2KL7,HE,0, is obtained i n a similar may to the molybdenum salt. The anhydrous salt crystallises in groups of large tablets. E. C. R. Some Alkali Phosphides. By C. HUGOT (Coinpi. rend., 1895, -121, 206--208).-When liquefied ammonia is brought in contactIXORQANIC CHEMISTRY.21 with a mixture of known quantities of red phosphorus and sodium or potassium, the sodammonium or potassammonium which is first formed is decomposed by the phosphorus wit>h liberation of hydro- gen, and the product remains in solution in the excess of ammonia. Potassium yields n red compound, P5K,3NH3, which when heated at 180' loses all its ammonia,, and leaves a brownish-red mass of the phosphide, P5K. Sodium yields a red product, P3Na,3NH,, which a t 180' loses all its ammonia, and leaves the phosphide P3Na. The potassium compound is not obtained quite pure, since potassa.mide is slightly soluble in liquefied ammonia, but this dit-ficnlty is not experienced in the casc of the sodium cornpound.Both phosphides are decomposed by moist air, with liberation of hydrogen phosphidc. Their other properties will be described subsequently. C. H. B. Determination of the Atomic Weight of Zinc. By THEODORE W. RICHARDS and ELLIOT F. ROGERS (Zeit. nnoiy. Chein., 1895, 10, 1-24).--The authors have determined the stoniic weight of zinc from the ratio of silver to zinc bromide and silver bromide to zinc bromide. The specific gravity of zinc bromide was found t o be 4.219 at 20". The zinc bromide employed in the first series of determinations was prepared by dissolving pure zinc oxide in pure hydrogen bromide, the pure zinc oxide being prepared by dissolving commercially pure zinc in dilute sulphuric acid, and allowi~g the solution to remain some weeks in contact with an excess of the nietnl. The filtered solution is then slightly acidified with sulphuric acid and treated with pure hydrogen sulphide until a considerable quantity of pure white precipitate is formed, and the filtrate from this is treated with chlorine water and fractionally precipitated with pure soda.The first precipitate, which contains iron and manganese is discarded, but the second precipitate after being well washed with water, is dissolved in pure nitric acid, treated with an excess of zinc carbonate, arid filtered ; the filtrate is treated with a small quantity of ammonium carbonate, and, after filtration, the zinc is precipitated with anirrio- nium carbonate. ' b e basic zinc carhonatc! tlius obtained is washed, heated in a platinum crucible by nienns of n spirit flame, and again washed and dried.The hydrogen bl-omide was prepared according to well- known methods, and puii tier1 by f mctionql distillation. I n the determination of the atomic weight, great care must be taken that the zinc bromide is free fkom every trace of water ; the metbod employed is that already described by the author for the analpis of strontium bromide (Abstr., 1895, ii, 314). The pure recrystallised or sublimed zinc bromide is heated for some time in n platinum boat i n R current of nitrogen containing hydrogen bromide, by which means all the water is removed without the slightest forrna- tion of oxybromide; the dry salt is then quickly transferred to .z desiccator and weighed. It is dissolved in water, precipitated with a slight excess of silver dissolved in nitric acid, and the silver brom- ide thus obtained is collected in a Gooch's crucible, and weighed.I n a second series of determinations, the filtrate was concentrated,22 ABSTRACTS OF CHEMICAL PAPERS. and the excess of silrer determined by precipitation with hydro- bromic acid. The first series of five experiments gave Zn = 65.459. The second series of four experiments gave Zn = 65.430 from the ratio Ag? : ZnBr,, and Zn = 65.423 fyom the ratio 2AgBr : ZnRI*,. The silrer bromide obtained in the last four experiments gave 57.444 per cent. Ag, which shows that the hydrogen bromide employed was free from chlorine and iodine, and that the precipitate contained no included zinc bromide. I n the third series of experiments, the zinc bromide was prepared by dissolving pure electrolytic zinc in pure bromine.A solution of zinc sulphate is prepared as described above, but after the trexhment with chlorine, pure soda is added, until a sniall precipitate is formed, and the mixture is allowed t o remain for some days, shaking occa- sionally ; the precipitate is then filtered off, and the zinc sulphate crys- tnllised from hot water. The solution of this zinc sulphate after being allowed to remain two days i n contact with pure electrolytic zinc in a platinum dish, is filtered, treated with ammonia, and electrolysed with a current of 1 to 14 amperes ; the zinc crystals formed being washed with ammonia, then with hydrochloric acid, aiid finally with water. The zinc is then dissolved in bromine, the solution filtered through asbestos, and the excess of bromine eliminated by heating on the water bath ; fiually the zinc bromide is either sublimed or distilled i n a special apparatus which is figured in the original paper, and so arranged that the sarople to be analysed is collected i n plati- num vessels.The zinc bromide is first dried at a gentle heat i n an atmosphere of carbonic anhydride, tben at a temperature slightly above its melting point in carbonic anhydride mixed with hjdrogen bromide, and finally a t 150' in a current of air until the exit gases show no trace of carbonic anhydride OP hjdi*o~en bromide. It is then weighed, dissolved in water, arid precipitated i n the dark with silver dissolved in nitric acid ; two equiralent solutions of silver afid hydrogen bromide are employed to determine the point at which au opalescence of equal intensity is produced in the clear supernatant liquid. Finally a slight excess of silver nitrate is added, and the pre- cipitate collected i n a Gooch's crucible and weighed.The mean of three experiments gave Zn = 65.402 from the ratio ZnBr, : 2Ag, and the mean of three other experiments give Zn = 65.406 from the ratio ZnBr2 : 2AgBr. The author coucludes that when 0 = 16 the most probable value for the atomic weight of zinc is 65.40. E. C. R. Electrolytic Preparation of Zinc and Lead. By EICHARD LOBENZ (Zeit. anoyg. Cherrz., 1895, 10, 78-116) .-Electrolysis of Fused Zinc Chloride.-The chief difficulty to be overcome in the electrolysis of zinc chloride, is to obtain the salt entirely free from water.The zinc chloride, which still contains water, is placed i n a V-tube of combustion glass, and heated t o quiet fusion. A carbon electrode is placed in each arm of the tube. Directly the current is started, a brisk evolution of gas, due to the presence of water, takes place at both electrodes; the gas evolved at. the positive electrode is at the com- mencement hydrogen chloride, but after some time chlorine is evolved ;INORGANIC CHEMISTRY. 23 meanwhile the evolution of gas a t the negative electrode diminishes, and zinc begins to be cleposited. During the deposition of the first few drops of metal, a brisk evolution of hydrogen takes place at the negative electrode. As the zinc which is deposited at first is not pure, b u t contains lead and other metals which may be present, the molten electrolyte is poured off into a similar V-tube as soon as the less posi- tive metals have been deposited, and the electrolysis is continued ; pure zinc is then deposited.The electrolyte, which now consists of pure zinc chloride, is a clear, limpid, highly refractive liquid, under which the molten zinc appears like mercury. It solidifies, on cooling, to a white, porcelain-like mass, and is the most hygroscopic substance the author has worked with. Fused lead chloride is easily electrolysed i n a similar way. Fused cadmium chloride is not so easily electrolysed ; chlorine is at once evolved at the anode, and at the cathode brownish-black clouds which dissolve in the electrolyte, whilst a small quantity of cadmium is deposited.The electrolyte contairis a lower chloride of cadmium, which can be obtained as a crystalline metallic powder by lixiviating the electrolyte with water; t h i s compound is diEcuit to dissolve in hydrochloric acid, and the solution does n o t at first give a precipitate with hydrogen sulphide, but, after some time, a jellow precipitate is suddenly deposited. I n the electroljsis of fused silver chloride, the silver is deposited as a brown mass, and when a small quantity of melted zinc or lead is placed in contact with the cathode, the silver dissolves in the molten metal. Silver chloride diesolves in zinc and lead chlorides, and, on subjecting the mixture to electrolysis, the silver is deposited first. The silver is also deposited when a zinc rod is placed in molten zinc chloride containing silver chloride.Copper chloride, dissolved i n zinc chloride, in which, however, i t is only slightly soluble, can be electrolgsed by employing a cathode of molten zinc, when all the copper is obtained as a zinc copper - alloy. Mixtures of zinc, silver, lead, copper, and cadmium chlorides on fusion give colourless electrolytes, which are easily manipulated. The addition of lead chloride t3 zinc chloride greatly increases the ease with which tlie fused salt is dehydrated by heat alone, and mag- nesium and calcium chloride produce the same effect. When such mixtures of fused metallic chlorides are electrolysed, the mPtals are deposited one after the other, and can be obtained pure by fractional elec trol pis. Mitli a mixture of lead and zinc chlorides containing cadmium chloride, after 20 amphe-minutes, the metallic regulus conisined 97-34 per cent.lead, 1.35 per cent. cadmium, and 1-30 per cent. zinc ; after 175 ampere-minutes, i t contained 1-50 per cent. lead, 2-55 per cent. cadmium, and 96.15 per cent. zinc, and after 335 amphre- minutes, pure zinc was deposited. With a mixture of lead, silver, and zinc chlorides, a separation of the silver and lead cannot be obtained ; after 2.5 ampGre-minutes, tlie legidus contained 60.6 per cent. silver, 8 per cent'. lead, and 7.5 per cent. zinc ; after 7.5 amp6re- minutes, S J per cent , 5 per cent., and 14 per cent. respectively, and24 ABSTRAOTS OF OHEMICAL PAPERS. after 27.5 ampere-minutes, 0.49 per cent., 95.96 pcr cent., and 2.5 per cent.; after 272.5 amphre-minutes, pure zinc was obtained. With a mixture of zinc: and silver chlorides, and employing a cathode of molten lead, the silver was easily separated; with a cathode of molten zinc, however, aEter 330 a.mpBre-minutes, the electrolyte still contained traces of silver. With II, mixture of copper and zinc chlorides, and employing a cathode of molten zinc, copper is deposited at once, befcre the current is started, and after 90 amphe-minutes pure zinc is obtained. A large number of experiments, fully described in the original paper, show that 0.9 volt is sufficient t o deposit zinc by this method, and a slightly lower roltage to deposit lead. The deposition of zinc is theoretical, 435.89 ampitre-minutes deposited 9 grams, whereas, theoretically, 8.86 grams should have been deposited.The author bases a method of wiritiing zinc and lead from their ores on the results of the above experiments. Ores containing chiefly zinc, with lead and small quantities of silver and cadmium, are roasted and treated with hydrochloric acid. When excess of acid is employed, the iron and aluminium are precipitated from the solution by the addition of zinc oxide, and the purified liquor evaporated and the residue fused. Ores which contnin chiefly lead are treated with dilute acetic acid, and the lead and silver. precipitated from the solu- tion by the addition of sufficient hydrochloric acid. After separa- tion of the lead and silver chlorides, the liquor is again used to lixiviate fresh portions of 01.0 until if becomes satnrated with zinc acetate. The acetic acid is then removed by treating the liquor with hydrogen chloride and distilling, and again used with fresh portions of the ore.A description of an apparatus suitable for carrying oat the operation on a technical scale i s given. The chlorine evolved during the electrolysis is converted into hydrochloric acid by the method described by the author (this vol., ii, 17). Chromates and Dichromates of the Heavy Metals. Bey JUL. SCEULZE (Zeit. anorg. Chem , 1895, 10, 148--154).-1n contradiction of the results obtained by Ihiiss and Unger (Abstr., 1895, ii, 355), the author has obtained the following chromiltes and dichromates in .a crystalline form. Copper diclrromate, CuCr,@, 4- 2H20, is obtained by saturating a cold solution of chromic acid, previously freed from sulphuric acid, with copper carbonate, aiid evaporating the greenish-brown solution under the air pump.It separates i n very lustroas, black crystals, is slightly hjgroscopic, and dissolves easily, and without decomposition, in cold water; when heated with water, however, i t decomposes, and is partially converted into a brown compound. It is identical with the salt described by Droge (Annalen, 101, 39). Copper chromate is obtained by heating the dichromate with copper oxide in a sealed tube at 220’. It crystallises in minute, brownish, transparent prisms, insoluble i n water, but easily soluble in acids or in chromic acid ; when boiled with water, it gradually decomposes, and yields the dichrornate and the salt 3Cu0,CrOa + 2Hz0.Cadmium dicliromate, CdCr207 + HzO, obtained in the same way E. C. R.1N 0 RGANIO CHEMISTRT. 23 as the copper salt, separates in orange-bromTn, cubic crystals, and dissolve.; easily, and without decomposition, in water. CatIrniunz chromate, obtained by heating the dichromate wit11 cadmium hydroxide, in a sealed tube, a t 200°, separates as a bright, orange-yellow powder, which appears crystalline under the micro- scope. When boiled with water, it yields the dichromate and :L brownish-yellow powder. The filtrate obtained in the preparation of the chromate, when allowed to remain for some time, deposited crystals containing 2H,O, and t h i s is the only chromate of tlie heavy metals which contains water of cryst allisation. Zinc dicAroniate, ZnCr20, + 3H20, crystallises in dark, reddisli- brown, crystalline crusts, and has similar properties to the above salts.Z i m chromate is obtained as a fine powder, which appears crystalline under the microscope; it is insoluble in water, easily soluble in acids, and is decomposed by boiling with water, yielding t l L c dichromatc and a greyish-yellow, crystalline basic chromate. Manganese carbonate dissolves in a cold solution of chromic acid in the proportion of 1 to 2, but the product obtained on evaporatioli was not crjstalline. It formed a black powder containing chromic oxide. Cobalt and nickel oxidea also dissolve easily in a cold solution of chromic acid in the ratio of 1 to 2. The author has attempted to prepare a chromic acid alum by adding potassium chromate to a solution of alumina in chromic acid, but in all cases potassium dichromate was formed.Carbides of the Metals of the Rare Earths. By OTTO PETTERS- E. C. R. SON (Bey., 1895, 28, 2419--2422).-Wlien the oxides of yttrium a i d lanthanum are mixed wit!i powdered carbon and reduced in a carbon crucible in the electric arc, carbides of the formulaMC, are produced- The end of the reduction is rendered evident by tlie appearance of flames, ayising from the vapour of the metal, which show a very brilliant spectixm, in which the most conspicuous lines are reversect. The carbides are crystalline and brittle, and have n golden yellow colour when freshly broken, but the surface is almost as rapidly at- tacked by the mcisture of the air as a fresh surface of metallic sodium, a thin grey layer of oxide being formed.They are deconi- posed by water with evolution of hydrogen aild carbnretted Lydrogeii, the hjdroxide of thc metal and graphitic carbon being deposited. Yttrium carhide has the sp. gr. 4.185, whilst that of Inratlzaimm carbide is 4.718; both of thc:e carbides contain 2-3 per cent. of graphitic carbon, wliich has not been included iii tlie conipositioir on which the formula is based. Draiyings are given of the simple electric furuace employed. A. H. Crystallised Anhydrous Manganese Sulphide. By A. MOURLOT (Compt. rend., 1895, 121, 20%--203).-W hen well dried. amorphous mairganese sulphide, mixed with a small quantity of s u l p ~ ~ u r , is subjected to the action of an arc from a current of 4U. ampAres and 20 volts for about 20 minutes, the upper part of tho fused mass, after cooling, is distinctly crystalline.With inore powerful currents, the sulpliide does not crgstallise so well. The26 ABSTRAOTS OF OHEMIOAL PAPERS. action of carbon bisulpllide and hylrogen snlphide a t a high tempera- ture on manganese prepared in the electrical ftirnace yields the amorphous sulphide only. The crystallised sulpliide is in the form of small, transparent, deep green octahedra, which have no action on polarised l i a h t ; sp. gr. = 3-92, hardness = 3.5 to 4. The fused sulphide is sufficiently hard to scratch qnartz ; sp. gr. = 4%6. The crystallised sulphide, prepared in the manner indicated, is identical in composition and physiFa1 properties with ulabandine ; i t has practically the saine chemical properties as the amorphous sulphide, but is less readily attacked by reagents.Fluorine has no action on it in the cold, but attacks it below a red heat with incandescence and the production of white fumes. Hydrogen is without action on the aulphide a t 1200°, and carbon does not reduce it under the influence of an arc from a current of 1000 amperes and 50 volts. C. H. B. Compounds of Ferrous Chloride and Nitric Oxide. By V. THOMAS (Compt. rend., 1895, 121, 204- 206).-The three compounds of ferrous chloride and nitric oxide (Abstr., 1895, ii, 271) have no appreciable tension of dissociation at the ordinary tenipernture either in a vacuum or in a current of a carefully dried, inert gas. Water dissolves the cornpourid, Fe2ClJ,2NO, without any evolution of gas, and no gas is evolved if the other two compounds art; added to a large proportion of water; but if water is allowed to drop on the solid compounds, gas is liberated in large quantity.Potassium hydroxide or ammonia behaves similarly with all three compounds, and produces a grejish-white precipitate which rapidly becomes bluish-green and, finally, black. There is no liberation of gas, and the liquid contains neither a nitrate nor a nitrite, nor ammonia; the solutions obtained by Gay's methods (Abstr., 1885, 1109), on the other hand, erolre large cliimtities of a mixt,nre of nitrous oxide and nitrogen. When the black precipitate, produced by alkalis in solu- tions of the Eolid compounds, is placed in a vacuum, it gives off a considerable quantity of almost pure nitrogen. If R solution of the compound Fe2C14,2N0 is precipitated with silver nitrate, there seem to be indications of the formation of silver hyponitrite ; but this sup- position could not be confirmed, and the phenomena are not shown hp the other two compounds.Nitric oxide is only very slowly absorbed by solutions of the compounds Fe2C14,N0 and 5Fe,C14,N0, and seems to act as an oxiclising agent. C. H. B. Ammonia and the Chlorides of Iron. Ey ALFRED S. MILLER (Arne?. C'lienz. J., 1895, 17, 570-571).-Anhydrous ferric chloride will absorb 6 mols. of ammonia, forming the cornpound FeC1,,6NH3 at ordinary temperatures ; five mol. are retained i n a perfectly dry atmosphere at the ordinary temperature, but a t 100' the compound becomes FeC1,,4XHB. The ammonia compound ia not deliquescent, and is insoluble in water, b u t loses ariimonia and chlorim when mashed ; it dissolves i n mineral acids, yieldiug red solutions.The compound showed a gradual dissociii tion ( s i c ) with formation of ammonium chloride, from 100° to 280' ; just below 280°, it was entirelyINORGANIC CHEBlIST BY. 27 dissociated. The compound absorbs dry chlorine with a considerable deyelopment of heat. Ferrous chloride absorbs approximately G mols. of ammonia at the ordinary temperature, forming a white powder, k'eC12,6h'H3, which readilj oxidises in air. Wherr heated at 100" in hydrogen, the com- pound became FeCI2,2NH,. Chromium Sulphate. By ALBERT RECOURA (Ann. Chim. Phys., 1895, [7], 4, 494--327).-This paper is mainly a re'sume' of work pre- viously published elsewhere (compare Abstr., 1891, 1430 ; 1892, 411 and 783; 1893, ij, 4iO and 528 ; 1894, ii, 382).It is shown that when a solution of the violet chromium sulphate is heated for some time at loo", i t becomes green, and that the solu- tion then contains free sulphuric acid and a basic salt formed accord- ing to theequatioir ~ C I - ~ ( S O * ) ~ + H20 = Cr,O(SO,), + HzS04. The salt thus formed is the sulphate of a radicle [Cr,0(S04)4](OH)2, which the author terms suZphochromyZ hydroxide. The violet sulphate, Cr,(S04)3 + 18H20, when heated to 90' loses water, and gives the compound Cr2S,Ol2 + 8H20, which is neither a sulphate nor yet a chromium salt. The same compound may be obtained from a solu- tion of the violet salt ; it is characterised by the ease with which it unites with 1, 2, or 3 mols of sulphuric acid or of a metallic sulphate, thus giving rise to the chromosulphuric acids and the chromo- sulphatea.Under special conditions, this compound can also unite with 5 or 6 mols. of sulphuric acid, yielding compounds with quite distinct constitutions and properties. The latter cowpounds are much less stable than the chromosulpluric acids; they lose sul- phuric acid a t 140°, and jield sulphochromic hydroxide, A. G. B. This is an acid of chromium which is characterised by the insolu- bility of all its salts. J. J. 8. Molybdenum Dihydroxychloride. By AD. VAXDENBERGHE (Zeit. unorg. Chew., 1895, 10, 47--59).--The author has determined the molecular weight of molybdenum dihydroxychloride by means of the boiliiig.point and fieezing point methods with the object of de- termining its constitution. The compound is prepared by heating molgbdic anhydride a t 200" in a current of dry hydrogen chloride ; it sublimes in lustrous, white crystals, and, when dowly cooled, in beau- tiful, bright yellDw needles, and is very hygroscopic. The determination of the molecular weight by means of the boiling point method was pcxformed in a modification of Beckmann's appa- ratus, and the molecular weight calculated from the formula M=Kp/Zt. With ether and acetolie as solvents, the numbers obtained agree with the theoretical value, 217, assnming that the cornpound is an atomic compound of the constitution MoO(OH),Cl,, that is, the action of hjdrogen chloride oti molybdic anhydride is analogous to its action on sulpburic anhydride. With methylic and ethylic slcol~ols as solvents, a smaller molecular weight, was obtained corresponding with t.hat required i f the compound I S dissociated iiito iis ionq, C1 and MoO,H,Cl.28 ABSTRACTS OF UEiEMICAL PAPERS.The determination OE t,he molecular weight by the freezing point method, using anhydrous acetic acid, gave results a.greeing with the numbers obtained with methylic alcohol by the boiling point method ; with water as tho solvent, however, numbers were obtained closely approaching 54.2, which is the number required, assuming that the compound is dissociated into the ions C1, CI, H and O:Mo*OH*O. The author has attempted, wifhout success, to determine tJie vapour deDsity of the conipound; it is already dissociated a t 15So and 181'.E. C. It. Molybdenum Bronzes. By ALFRED STAVENHAGEN and E. ENGELS (Bey., 1895, 28, 2280-2281).-When acid sodium molybdftte, Na6Moi02$, is fused find submitted to electrolysis, a substance is formed which crystallises i n quadratic prisms of a deep blue colour. It is insoluble in hjdrochloric acid, but dissolres in aqua regia and in alkalis. The substance contains 6 per cent. of sodium acd 62.7 per cent. of molybdenum, and is looked on by the authors as a sodium molybdenum bronze. A. H. Preparation of Tin Tetrachloride in large Quantities. By RICHLRD LORENZ (Zeit. ano?g. Chem., 189.5, 44-46).-Tin teti.3- chloride is most easily prepared by the action of chlorine on tin at the ordinary temperature. The most suitable apparatus is a tube closed a t one end, 5 to 6 cm.wide, anti 75 to 100 cm. long, fitted with a condenser and a tube, by means of which dry chlorine can be passed to the botlom of the tube, where it bubbles throngh a little tin tetrachloride. The tube is filled nearly to the top with granulated tin. 14 to 2 kilos. of the tetrachloride are easily prepared in about one hour. The product is pure, and boils at 114". E. C. R. Chemistry of the Cyanide Process for the Extraction of Gold from its Ores. By GEORGE A. GOYDER (Chem. Neuts, 1895, 72, 80-&2, 95--97).--1'ho amount of simple cyariide iu a solution con- taining certain double cyanides, such as the ziuc potassium cyanide in the final solution of the cjanide process, cannot be accurately estimated by titration nith standard silver nitrate in the presence of a littole potassium iodidb, because the final reaction is indistinct, nod, moreover, an amount of silver nitrate is used up by these double cyanides, which increases continuously with the temperature, with the amoiint of fresh simple cyanide added, and with the dilution. The author has observed that hydrocyanic acid does not decolorise phenolpht halejin, that potassium cyanide is alkaline to it, and that the double cyanides are neutral, and on t h i s has based the fallowing method of testing the final liquors for simple cyanide, which, how- ever, is not applicable in the presence of caustic alkalis or alkali carbonates ; alkali hydrogen carbonates do not interfere.100 C.C. of the solution is titrnted with decinormd hydrochloric acid, using 1 C.C. of 0.05 per cent. solution of phenolphthalein as indicator, 1 C.C. of acid = OtJOci5 1)er cent. of potassium cyanide. The estimation of all the cyanides, except the iron, mercury, or copper potassium cyauidte, mi19 be eflected by the silver nicthod i f the solution beMISERALOOIOAL CHEMISTRY. 29 mixed with half its volume of 5 per cent. caustic soda, filtered, and about 15 C.C. of the filtrate taken for titration. The following are the numbers per cent. obtained from the analysis of the final solution from the treatment of the Mount Torrens ore by the cyanide process. C u 0*0030, Z n 0.0178, Fe 0.0061, Ca 0.0145, Mg 0.0042, K 04609, Na 0.0645, C1 0.0875, CN 0-04i7, SO, 0.0401, CO, 0.0333, and traces of Co, Hg, Ag, and Au. Numbers, too, are given showing how the progress of the extraction may be followed by observing the- strength of the outflowing solution. Data are also furnished showing that without further comminu- tion little or no gold can be extracted by potassium cyanide from the tailings. Furthermore, i t is shown that hydrocyanic acid in the presence of air, aid the double cyanides of zinc and potsssium and of copper and potassium exert a solvent actionon gold, but that the cor- responding mercury salt does not'. Allowing one lot of cyanide solution to drain away from the ore undergoing extraction before adding a fresh lot m-as found to be destructive to the cyanide vithout commen- surate benefit. The destructiveness of ferrous and othcr soluble metallic salts is commented on. D. A, L.