INORGANIC CHEMISTRY. I n o r g a n i c Chemistry. 149 Action of the Galvanic Current on Chlorides and Chlorates. By A. LIDOFF and W. TICHOMIROFF (Jour. Russ. Chern. Xoc., 1882, 341- 349).-In a former paper (Abstr., 1882, 925) the authors have found that by the action of the electric (galvanic) current on a solution of chlorides, hypochlorites are first formed, which, by an elevation of tem- perature, are converted into chlorates. But later on they found that even a t the ordinary temperature, as soon as the solution becomes more concentrated, hjpochlorites are converted into a mixture of chlo- rates and chlorides by the sole action of the current. They propose to apply this process to the manufacture of chlorates, more especially of the sodium salt, which is difficult to prepare in the ordinary way.On150 ABSTRAC’J S OF CHElllICAL PAPERS. acting with a current of a powerful Gramnie machine for 25 hours, on a solution of 400 granis of potassium chloride in 900 grams of water, 210 grams of crystals, containing 70 per cent. of chlorate, were obtained. The crystals contain, together with potassium chlorate, a considerable quantity of the chloride, and 5-12 per cent. of carbon from the electrodes. As soon as about 30 per cent. of the original salt is transformed into the clllorate, the positive electrode is most strongly corroded, and no further separation of the crystals from the liquid takes place. If, instead of a high tension-current (2 electrodes) a divided current (8 electrodes) is employed, far less chlo~ide is converted into chlorate in tlie same space of time.The corrosive action of the liquid on the positive electrode is due to its oxidation by the oxygen of the potassium chlorate, which is reduced to chloride (about 30 per cent. in 10 hours). For this reason, potassium chloride csnnot be com- pletely converted into chlorate, but a limit is reached after some time, when the energy of formation of potassium chlorate from the chloride becomes equal to the energy of its decomposition. Electrodes of another material than carbon cannot be used for the conversion of chlorides into chlorates, for all metals, even platinum, are corroded by the chlorine which is set free at the same time. If, however, a solu- tion of potassium chlorate be electrolysed by means of platinum electrodes, 110 chlorine, but ozone, is evolved on the positive pole.At tlie same time crystals of potassium perrhlorate separate from the liquid, and oiily traces of potassium chloride are formed at the same time. I n this respect the act’ion of electricity on potassium chlorate is analogous to the action of heat on the same salt; in both cases oxygen is evolved, and potassium chlorate and chloride are formed, although the proportion in the quantities of these two salts is widely different. The corrosion of carbon in the above case is due t o the action of ozone, and the products of this action in presence of water Oxidation of Carbonic Oxide by Palladium Hydride and Oxygen. By M. TRAUBE (Ber., 15, 2325--2326).--The changes which occur when carbonic oxide is converted into the anhydride by the action of palladium hydride snd oxygen are as follows:-In the first place palladium hydride and moist oxygen form hydrogen per- oxide, and this compound in presence of metallic palladium oxidises are mellitic and hydromellitic acids. B.R. carbonic oxide t o carbonic anhydride. w. c. w. Compressibility of Nitrogen. By E. H. AMAGAT (Co?npt. rend., 95, 638--641).-A summary of t,he experiments made by Cailletet and by the author with a view to determine the compressibility of nitrogen. Curves are given representing the results obtained by both observers. The author considers Cailletet’s method inferior i n accuracy to his own. The curve representing Cailletet’s results is rery irregular, whilst t h a t representing the author’s results is perfectly regular.Black Phosphorus. By P. THENARD (Compt. rend., 95, 409--4110). -A quantity of phosphorus was being cast in the usual way, and a, C. H. B.IWORGAXIC CHEMISTRY. 151 dozen sticks had been obtained of the usual colour, when the thirteenth suddenly blackened atl the moment of congelation. Subsequently a second stick, about 20 cm. long, blackened for about 4 cm. of its length, the remainder being unchanged. A portion of the black phos- phorus was brought in contact with ordinary phosphoriis, in a state of superfusion a t 10" under ice. I n the first experiment, the white phos- phorus became black on solidifying, but the s3me effect was not again obtained once in more than twenty experiments under precisely similar conditions. The specimen of black phosphorus became white when fused, and remained white if cooled suddenly, but if super-cooled it again became black when brought in contact with either black or white phosphorus.Black phosphorus dissolves almost entirely in carbon bisulphide, leaving a slight yellow residue apparently consist- ing of amorphous phosphorus. Neutral Phosphates of the Alkalis. By E. FILHOL and SENDERENS (Bied. Centr., 1882, 641).-Careful neutralisation of phos- phoric acid with sodium hydroxide results in the formation of a mixture which reacts on red or blue litmus ; crysbals obtained from the solution contain 1 mol. of the mono- and 1 mol. of the di-sodium phosphate. Neutral potassium or ammonium phosphates have not been obtained, whilst potassium sodium and sodium ammonium phos- phates crystallise readily.Calcium Chloride. By A. WEBER (Bey., 15, 2316--2317).- Calcium chloride dried a t 180-200" is practically anhydrous. It contains from 0.12 to 0.24 per cent. of water and 0.047 per cent. ClaO. C. H. B. E. W. P. w. c. w. Properties of Pure Aluminium. By J. W, MALLET (Chern. News, 46, 178).-Sp. gr. a t 4" = 2.585 ; atomic vol., 10.45 ; sp. heat = 0.2253 between 0-100" ; atomic heat, 6.09" ; less fusible than the commercial metal, and less easily acted on by alkalis and acids. It is nearly pure tin-white, with no bluish tinge, and has a lustre like that of tin. It is more malleable and less easily hardened by hammering than ordinary aluminium. E. W. P. Decomposition of Phosphate by Potassium Sulphate at High Temperatures. By €3. GRANDEAU (Comnpt.rend., 95, gal-- 922).-Debray (BUZZ. SOC. Chim., 3, 251) has shown that on heahing to a high temperature aluminium phosphate with excess of an alka- line sulphate, an alkaline phosphate and crystallised aluminium are obtained. This reaction has been used by Derdme (Compt. r e d , 89, 92.5, and this Journal, 38, 286) for the separation of phosphoric acid from iron and aluminium. To determine the conditions of the re- action, a mixtiire of aluminium phosphate and potassium sulphnte was heated for several hours in a platinum crucible. At a high temperature, not only is alumina formed, but also a crystalline double phosphate of aluminium and potassium. At a still higher tempe- rat me, the quantity of alumina increases, but even on very vigorous heating it is impossible to completely decompose the double phos-152 ABSTRACTS OF CHEMICAL PAPERS.phate. Similar results were obtained by subst,ituting phosphates of glucinum, cerium, and didymium for aluniinium phosphate. But when phosphates of calcium, magnesium, &c., were used, the doable phosphate alone was formed under the conditions of the experiment ; whilst with nickel and cobalt; phosphates results similar to those with aluminium phosphates were obtained. With chromium and uranium phosphates, the final products are potassium chromate and uranate. The investigation is being continued. Determination of the Equivalent of Thorium. By L. I?. NILSON (Compt. j-end., 95, 729--730).-As a mean of ten determiua- tions, the author finds 58.10 to be the equivalent of thorium, that of oxygen being 8, and of sulphur 16.H e makes the atomic weight, therefore, to be 232.36. These results were obtained by calcining two different specimens of the sulphate, a aud b. Specimen b was obtained from the mother-liquors of a. The first six determinations were made on specimen a, which contained nine molecules of water. I n these six experiments the author used the hydrated salt, because the dehy- drated substance was found to be extremely hygroscopic. In the other four experiments this was impossible, because specimen b (tlie crystals of which differed from those of specimen a ) contained only eight molecules of water, and absorbed water during the process of weighing. I n the latter four experiments, therefore, the anhydrous sulphate was used.The two specimens gave practically identical results. L. T. 0's. Sulphate a. Water. SO3. Thoa. Equiv. At. Wt. Mean of six experiments 27.573 27.336 45.091 58.11 232.43 Sulphate b. Mean of four experiments - 37.703 62.297 58.09 232.30 The author concludes by drawing attention to the wide diwrepancies in the values of the atomic weight as determined by other chemists. E. H. R. Metallic Thorium. By L. F. NILSON (Conyf. rend., 95, 727- 729).-The author obtains metallic thorium by heating with sodium i n an iron crucible a mixture of the anhydrous double chloride of thorium and potassium with sodium chloride. After treatment of the residue with water, metallic thorium remains as a heavy greyish brilliant powder. Examined under the microscope, the powder is seen to con\ist of minute crystals, more or less brilliant and united in groups. The metal is brittle and almost infusible.The powder assumes a metallic lustre under pressure, is unalterable in air up to 120", takes fire in air or ox)-gen below a red heat, and burns with dazzling brilliancy, leaving a perfectly white oxide. It takes fire when heated with chlorine, iodine, bromine, and sulphur. It is not attacked either by hot or by cold water. Dilute sulphuric acid causes a feeble evolution of hydrogen in the cold, becoming more rapid on the application of heat, but the metal is attacked slowly; hot con- centrated sulphuric acid also acts but slowly, disengaging sulphurousINORGANIC CHEMISTRY. 153 anhydride. Nitric acid, whether hot or cold, strong or dilute, exerts no sensible action.Dilute hydrochloric acid dissolves the metal slowly even when heated, but concentrated acid attacks it very easily. Aqua regia acts like hydrochloric acid. The metal obtained by hhe author behaves, therefore, exactly like that obtained by Berzelius. The mean sp. gr. is nearly 11; this is much higher t,han that found by Chydenius (7.657 to 7.795) : hence the specimen obtained by the latter chemist must have contained much impurity, probably derived from the glass tube in which it was preptred. The densities of two different specimens of the oxide were 10.2207 and 20.2198 respectively. These numbers are again much higher than those obtained by Berzelius, Damour, and Chydenius (9.402, 9.366, 9.288). Admitting that the metal is quadrivalent, the atomic volume is 21.1.This number coincides with the atomic volume of zirconium (21*7), cerium (21*1), lanthanum (22.6), and didymium (21.5) ; and this fact serves to confirm the author’s opinion that the rare earth- metals form a series of quadrivalent elements. Magnesia Alba. By R. KRAUT (Arch. Pharm. [ 3 ] , 20, 180-187). -In this criticism of Beckurts’ paper on the composition of magnesia aZbu (this vol., p. 13), the author shows that analytical errors have crept in, as no direct estimation of the water lost by heating was made, &c.; the formula proposed by Beckurts therefore is incorrect, and the original formula 5Mg04C02,Hz0, as proposed by Kraut, is the right one; also by boiling for some time, the composition may be altered to 4Mg0,3COZ,6HzO, but never to 7Mg0,5C02. Separation of Gallium.By L. DE BOISBAUDRAN (Cowzpt. Tend., 95, 410-413 ; 503-506. See also Abstr., 1882, 897, 1323).--From Indium .-Precipit#ation of the gallium by potassium ferrocyanide, in presence of hydrochloric acid, is to be recommended only when it is required to separate a little indium, together with other metals, such as aluminium and chromium. The following is the only trustworthy method :-The moderately concentrated solution is boiled for some minutes with a slight excess of potassium hydroxide ; the precipitated indium hydroxide retains small quantities o€ gallium, which may be removed by a repetition of the process. The alkaline solutioas contain only very slight traces of indium ; to remove these, hydrochloric acid is added in slight excess, and the gallium and indium are precipitated together by boiling with an excess of ammonia, or better, by means of cupric hydroxide.The gallium and indium chlorides are then converted into sulphates; the slightly acid solution mixed with a quantity of ammonium sulphate rather more than sufficient to convert the gallium into alum is evaporated to small bulk, and, after cooling, mixed with four or five times its volume of alcohol of 70 per cent. Gallium alum is thus thrown down as a crystalline powder, which is washed once or twice with alcohol, dissolved in warm water containing a minute quan- tity of sulphuric acid, and reprecipitated. By several repetitions of tlhis process, the gallium is obtained in the form of alum, free from indium. The alcoliolic washings, which contain small quantities of gallium and indium, are evaporated to small bulk, the metals pre- Alkalis ha.ve no action.E. H. R. E. W. P. VOL. XLIV. m154 ABSTRACTS OF CHEXICAL PAPERS. cipitated by boiling with ammonia or by means of cupric hydroxide, the precipitate dissolved in hydrochloric acid, and the solution boiled with a slight excess of potassium hydroxide; a small quantity of indium hydroxide is thus obtained free from gallium. The galliuin remaining in solution may be separated as alum. Usually the indium dissolved by tlie potash is removed by four crystallisations of the ammonium-gallium alum ; but if the gallium hydroxide contains more than 4 per cent. of indium hydroxide, seven or eight crystallisations are necessary. Froin CadnLiurrz.- In presence of much free hydrochloric acid, cadmium is not completely precipitated by hydrogen sulphide, whilst if the solut'ion is but feebly acid, the cadmium sulphide contains gallium. The somewhat acid solution is treated with hydrogen sulphide, the precipihate redissolved in hydrochloric acid, the solution diluted, and again treated with hydrogen sulphide. By two or three repetitions of the process, the greater part of the dadmium is obtained as sulphide free from gallium. The filtrates which contain the gallium, mixed with a little cadmium, are evaporated to expel excess of acid, dilutled with water, and saturated with hydrogen sulphide. The cadmium sulphide thus thrown down is reprecipitated two o r three times. Excess of boiling potassium hydroxide precipitates cadmium oxide, and dissolves gallium hydroxide ; the cadmium oxide is redissolved and again precipitated, in order to separate the last traces of gallium.If the amount of cadmium is large, this process must be repeated four or five times. The alkaline solution which contains gallium and a small quantity of cadmium is slightly acidified wjth hydrochloric acid, and the gallium precipitated by means of cupric hydroxide, the filtrate is mixed with ammonium acetate, and treated with hydrogen sulphide, which throws down copper and cadmium : this precipitate is dissolved in aqua regia, evaporated with hydrochloric acid, and hydrogen sulphide is passed into the strongly acid solution ; copper sulphide is thus precipitated, whilst cadmium remains in solution.The following methods are more rapid:-(1.) The solution, which must contain a sufficient quantity of ammonium chloride, is boiled with excess of ammonia: cadmium then remains in solution, and gallium hydroxide is precipitated ; this precipitate is redissolved and again precipitated, in order to remove the last traces of cadmium. (2.) Gal- lium is precipitated by means of potassium ferrocyanide in a solution which contains at least one-third of its volume of strong hydrochloric acid ; the cadmium ferrocyanide remains in solution. (3.) Cupric hydroxide precipitates gallium on gently warming ; the precipitate retains small quantities of cadmium, which may be removed by a repetition of the process. (4.) When it is necessary to remove iron as well as cadmium, the warm solution is reduced by metallic copper and then mixed with a slight excess of cuprous oxide: the pre- cipitated gallium hydroxide contains traces of cadmium, which may be removed by reprecipitation.The reactions with cupric hydroxide, and with metallic copper and cuprous oxide, are the most satisfactory. Fronz Ur.cr.nium.-(l.) The boiling slightly acid solution of the chloride is treated with cupric hydroxide ; the precipitate is then dis-INORGANIC CHEMISTRY. 155 solved in hydrochloric acid, diluted, and again precipitated with cupric hydroxide, the treatment being repeated four or five times. (2.) If it is required to separate iron a t the same time, the solution is reduced with metallic copper, and then boiled with excess of cuprous oxide; tbe precipitate is redissolved and the treatment repeated about four times.Neither of these methods is affected by the presence of con- siderable quantities of alkaline salts. (3.) The slightly acid solution of the chloride is mixed wit11 an excess of acid ammonium acetate, zinc chloride free from gallium added, and the liquid is treated with hydrogen sulphide : the zinc sulphide formed carries down the gallium, whilst the uranium remains in solution. The precipitate is difficult to wash and must be redissolved in hydrochloric acid, and again preci- pitated in presence of an acetate. The zinc and gallium are separated by the method previously described. (4.) The uranium is preci- pitated in the form of alkaline uranate by adding a slight excess of potassium hydroxide, the precipitate dissolved in hydrochloric acid, and again precipitated. To remove traces of uranium from the fil- trate, the latter is slightly acidified with hydrochloric acid, and boiled with cupric hydroxide.When the potassium hydroxide contains car- bonate, the quantity of uranium in the filtrate is increased. From Lead.-(1.) The slightly acid solution of the chloride is boiled with cupric hydroxide, the last trace of lead being removed by a second precipitation. The reagents must be free from sulphuric acid. This method is very accurate, and may be used to separate gallium sulphat,e from the minute quantities of lead which remain in solution after precipitation of lead as sulphate. (2.) The solution of chloride o r sulphate is boiled with metallic copper and then with cuprous oxide, traces of lead being removed by a second precipitation. If a solution of the chlorides is used, the presence of sulphuric acid in the reagents must be avoided.(3.) The moderately acid solution is treated with hydrogen sulphide, the filtrate evaporated almost to dryness to expel free acid, diluted with water, and again treated with hydrogen sul- phide. If sulphuric acid is present, i t should be partially neutralised with ammonia. To extract the gallium retained by the lead sulphide, the latter is treated with strong hydrochloric acid, alcohol is added, the liquid is filtered, and the filtrate, after evaporation to expel water and alcohol, is diluted, and saturated with hydrogen sulphide. (4.) The gallium is then precipitated as ferrocyanide by means of potassium ferrocyanide in a solution containing one-third or one-fourth its volume of stroug hydrochloric acid.A second precipitation is sometimes necessary in order to remove the last traces of lead. (5.) The solu- tion is mixed with sulphuric acid, and two volumes of alcohol of 90" added; the precipitated lead sulphate, after being washed with alcohol acidified with sulphuric acid, is suspended in dilute hydrochloric acid and treated with hydrogen sulphide; and the filtrate, after being boiled to expel excess of the gas, is treated with cupric hydroxide to precipitate the last traces of gallium. The gallium in the alcoholic solutions is precipitated by cupric hydroxide, after boiling off the alcohol. (6.) The solution is mixed with twice its volume of 90 per cent.alcohol ; a slight excess of hydrochloric acid is added, and the precipitated lead chloride is washed with acidulated alcohol, whereby it nz 2156 ABSTRACTS OF CEEMICAL PAPERS. is obtained free from gallium. The filtrate is evaporated to small bulk, the nitric acid removed, and the liquid treated either with hydro- gen sulphide, with cupric hydroxide, or with metallic copper and cuprons oxide. C. H. B. Separation of Gallium. By L. DE BOISBAUDRAN (COW& re12d., 95, 703-706) .--Xepayation from Tin.-Sulphide of tin pre- cipitated from a hydrochloric acid solution containing tin and gallium, retains none of the latter metal. On adding hydrochloric acid in excess to a solution of the sulphides of tin and gallium in an alkaline sulphide, sulphide of tin free from gallium is thrown down.Salts of manganese added to a solution of the mixed sulphides in an a1 kaline sulphide give a precipitate of manganese snlphide, which contains gallium: this makes it possible to extract the latter metal from large quantities of sulphide of tin. The author draws atten- tion to one or two points, of which notice must be taken in analysing mixtures containing gallium. A solution containing even a con- siderable amount of gallium is not precipitated by potassium ferro- cyanide if a large amount of stannic chloride is present; so that tin must be separated before attempting to estimate gallium by ferro- cyanide. Tin and gallium, when alloyed, cannot be completely separated by nitric acid, because the metastannic acid formed retains sensible quantities of gallium, even after prolonged washing with nitric acid.It is difficult to obtain a complete separation of gallium and tin by precipitating the latter metal with zinc, because in a solu- tion strongly acid the tin is not entirely thrown down, and in a nearly neutral solution a certain quantity of gallium becomes insoluble. Finally, tin dioxide, precipitated by boiling with sulphuric acid, retains much gallium. Xeparation from Antimony.-Gallium may be separated from anti- mony by sulphuretted hydrogen, or by addition of an acid to a solution of the sulphide in an alkaline solution, just as described in the case of tin, except that in the case of the solution in the alkaline sulphide, it is advisable to repeat the process. Potassium ferrocyanide precipitates gallium from a solution containing antimony, but the precipitate contains traces of the latter metal, which must be removed by dis- solving it in potash and reprecipitating by addition of a large excess of hydrochloric acid and a few drops of ferrocyanide.Salts of man- ganese can be used to separate traces of gallium from antimony, just as in the case of tin. Precipitation of the antimony by zinc does not answer well. E. H. R. Compouhds of Tin Disulphide and Diselenide. Compt. rend., 9 5, 641- 644) .---Potassiunz thiostannafe, By A. DITTE SnS,,K2S,3H,0, forms transparent colourless or very sIightly yellow prisms, very solu- ble in water, but decomposed by a large quantity of that liquid, with precipit,ation of hydrated stannic sulphide.It is obtained by dissolv- i n g stannous sulphide in a solution of potassium polysulphide, or more easily by boiling a concentrat,ed solution of potassium mono-INORQANIC CBERIISTRY. 157 sulphide with the theoretical amount of sulphur and a slight excess of tin, and evaporating the clear yellow solution by boiling or in a vacuum. Potassium seZen,iothiostarLi~,ate, SnSe2,K2S,3H20, is obtained by substituting selenium for sulphur in the preceding operation. It forms yellow octohedrons, very soluble in water, with formation of a rose or red solution, according to the degree of concentration. Bokh the solution and the crystals alter when exposed to air, black crystal- line selenium being liberated. SnSez,K2Se,3Hz0, is obtained by saturating a solution of potassium selenide with tin diselenide and evaporating in a vacuum.It forms crystals which alter rapidly when exposed to air. Sodium thiostnnnate and sodium seleniostannate are obtained in the same way as the corresponding potassium compounds, and have similar properties. Ammomiurn thio- stannate, 3Sn Sp, (NHd)zS,6H,0, is obtained by heating sheet tin with a solution of ammonium polysalphides, and evaporating the clear yellow liquid in a vacuum over potassium hydroxide and sulphuric acid. It forms yellow plates, which are decomposed by water with sepnration of hydrated stannic sulphide. The crystals a1 ter quickly even in a vacuum, losing water and acquiring a superficial violet tint. When gently heated, t$hey lose water, ammonium sulphydrate, and sulphur, a residue of tin salphide being left.Ammunium seleniotlzio- stnnnate, 3SnSe2,(NH4),S,3H,0, is obtained by treating an excess of hydrated tin diselenide with a concentrated solution of ammonium sulphydrate in the cold, filtering, and evaporating the red filtrate in a vacuum over potassium hydroxide and sulphuric acid. It forms yellowish-red plates, less stable than the preceding compound. The crystals are decomposed by water, with separation of red flakes of tin diselenide. Tellurium dissolves in boiling concentrated solutions of the alkaline sulphides, but yields no compounds with tin analogous to those already described. Tellurium is deposited in crystals when the solu- tion cools. Barium tkiostannate, SnSz,BaS,8H20, obtained by dissolving tin in a boiling solution of barium polysulphides and evaporating the solu- tion in a vacuum, forms transparent citron-yellow crystals, soluble in cold water without decomposition.From this solution dilute acids immediately precipitate yellow fitannic sulphide. Strontium thio- stannate, SnS2,SrS, 12Hz0, produced in a similar manner, forms bulky, transparent, colourless prisms, soluble in cold water without decom- position. Ca Zeium tlAmkmanate, SnS2,2CaS, 14H20, also obtained in a similar manner, forms transparent citron- yellow crystals, soluble in cold water without decomposition. Potassium se Ze?aiostunnate, C. H. B. Preparation of Lead Dioxide. By A. FEHRMANN (Bey., 15, 1882). -A concentrated solution (60-70" C.) of lead chloride is treated with solution of chloride of lime until a filtered sample does not show further separation of the dioxide ; the latter is then filtered off and washed out of contact with air.Lead dioxide so prepared is quite pure and nearly black, and keeps best in the moist state. When158 ABSTRACTS O F CHEMICAL PAPERS. prepared from sugar of lead it is not so cheap, and liable to undergo decomposition from the impurities of the lead acetate. Barium Compounds of Bismuth Peroxide. By I. MESCHTCHER- SKY (Journ. Russ. Chem. SOC., 1886, 280--281).-0n fusing a mixture of bismuth trioxide, baryta, and potassium chlorate, a black mass is obtained, which, when washed with water, begins to decompose, with evolution of oxygen. The black or reddish-brown residue remaining after the extraction of soluble salts by water consists of compounds of bismuth peroxide with barium, and decomposes hydrochloric acid with evolution of chlorine.Analogous compounds with calcium or magne- sium could not be obtained. If the above compound has been well washed with water, it does not lose oxygen under pure water, but decomposition takes place suddenly in contact with barium peroxide or solution of potassiiim chlorate. Fusion with potassium nitrate gives rise to compounds containing more oxygen, e.g., one of the following composition : 14Ba0, 5Bi205, S O 2 , 3H20. A Hydrate of Molybdic Acid. By F. PARMENTIER (Compt. rend., 95, 839--841).-The author has examined the yellowish crystalline substance which always separates after a time from solutions of alka- line molybdates in nitric acid. He finds that it contains no nitrogen, b u t is a hydrate of molybdic acid, having the composition Mo03,2H20.This substance is not formed in hydrochloric acid solutions of alkaline molybdates, It is very sparingly soluble in water, a litre dissolving only 0.5 gram a t 15". The crystals are efflorescent, and lose half their water in a vacuum over sulphuric acid. Heated to 200°, they lose all their water, and leave a white residue which sublimes completely on further heating. E. H. R. J. K. C. B. B.INORGANIC CHEMISTRY.I n o r g a n i c Chemistry.149Action of the Galvanic Current on Chlorides and Chlorates.By A. LIDOFF and W. TICHOMIROFF (Jour. Russ. Chern. Xoc., 1882, 341-349).-In a former paper (Abstr., 1882, 925) the authors have foundthat by the action of the electric (galvanic) current on a solution ofchlorides, hypochlorites are first formed, which, by an elevation of tem-perature, are converted into chlorates.But later on they found thateven a t the ordinary temperature, as soon as the solution becomesmore concentrated, hjpochlorites are converted into a mixture of chlo-rates and chlorides by the sole action of the current. They propose toapply this process to the manufacture of chlorates, more especially ofthe sodium salt, which is difficult to prepare in the ordinary way. O150 ABSTRAC’J S OF CHElllICAL PAPERS.acting with a current of a powerful Gramnie machine for 25 hours, ona solution of 400 granis of potassium chloride in 900 grams of water,210 grams of crystals, containing 70 per cent.of chlorate, wereobtained. The crystals contain, together with potassium chlorate, aconsiderable quantity of the chloride, and 5-12 per cent. of carbonfrom the electrodes. As soon as about 30 per cent. of the originalsalt is transformed into the clllorate, the positive electrode is moststrongly corroded, and no further separation of the crystals from theliquid takes place.If, instead of a high tension-current (2 electrodes) a dividedcurrent (8 electrodes) is employed, far less chlo~ide is converted intochlorate in tlie same space of time. The corrosive action of the liquidon the positive electrode is due to its oxidation by the oxygen of thepotassium chlorate, which is reduced to chloride (about 30 per cent.in 10 hours). For this reason, potassium chloride csnnot be com-pletely converted into chlorate, but a limit is reached after some time,when the energy of formation of potassium chlorate from the chloridebecomes equal to the energy of its decomposition.Electrodes ofanother material than carbon cannot be used for the conversion ofchlorides into chlorates, for all metals, even platinum, are corroded bythe chlorine which is set free at the same time. If, however, a solu-tion of potassium chlorate be electrolysed by means of platinumelectrodes, 110 chlorine, but ozone, is evolved on the positive pole. Attlie same time crystals of potassium perrhlorate separate from theliquid, and oiily traces of potassium chloride are formed at the sametime. I n this respect the act’ion of electricity on potassium chlorateis analogous to the action of heat on the same salt; in both casesoxygen is evolved, and potassium chlorate and chloride are formed,although the proportion in the quantities of these two salts is widelydifferent.The corrosion of carbon in the above case is due t o theaction of ozone, and the products of this action in presence of waterOxidation of Carbonic Oxide by Palladium Hydride andOxygen. By M. TRAUBE (Ber., 15, 2325--2326).--The changeswhich occur when carbonic oxide is converted into the anhydride bythe action of palladium hydride snd oxygen are as follows:-In thefirst place palladium hydride and moist oxygen form hydrogen per-oxide, and this compound in presence of metallic palladium oxidisesare mellitic and hydromellitic acids.B. R.carbonic oxide t o carbonic anhydride. w. c. w.Compressibility of Nitrogen. By E. H. AMAGAT (Co?npt. rend., 95,638--641).-A summary of t,he experiments made by Cailletet and bythe author with a view to determine the compressibility of nitrogen.Curves are given representing the results obtained by both observers.The author considers Cailletet’s method inferior i n accuracy to his own.The curve representing Cailletet’s results is rery irregular, whilst t h a trepresenting the author’s results is perfectly regular.Black Phosphorus. By P. THENARD (Compt. rend., 95, 409--4110).-A quantity of phosphorus was being cast in the usual way, and a,C. H. BIWORGAXIC CHEMISTRY. 151dozen sticks had been obtained of the usual colour, when the thirteenthsuddenly blackened atl the moment of congelation.Subsequently asecond stick, about 20 cm. long, blackened for about 4 cm. of itslength, the remainder being unchanged. A portion of the black phos-phorus was brought in contact with ordinary phosphoriis, in a state ofsuperfusion a t 10" under ice. I n the first experiment, the white phos-phorus became black on solidifying, but the s3me effect was not againobtained once in more than twenty experiments under precisely similarconditions. The specimen of black phosphorus became white whenfused, and remained white if cooled suddenly, but if super-cooled itagain became black when brought in contact with either black orwhite phosphorus. Black phosphorus dissolves almost entirely incarbon bisulphide, leaving a slight yellow residue apparently consist-ing of amorphous phosphorus.Neutral Phosphates of the Alkalis.By E. FILHOL andSENDERENS (Bied. Centr., 1882, 641).-Careful neutralisation of phos-phoric acid with sodium hydroxide results in the formation of amixture which reacts on red or blue litmus ; crysbals obtained fromthe solution contain 1 mol. of the mono- and 1 mol. of the di-sodiumphosphate. Neutral potassium or ammonium phosphates have notbeen obtained, whilst potassium sodium and sodium ammonium phos-phates crystallise readily.Calcium Chloride. By A. WEBER (Bey., 15, 2316--2317).-Calcium chloride dried a t 180-200" is practically anhydrous. Itcontains from 0.12 to 0.24 per cent. of water and 0.047 per cent.ClaO.C. H. B.E. W. P.w. c. w.Properties of Pure Aluminium. By J. W, MALLET (Chern.News, 46, 178).-Sp. gr. a t 4" = 2.585 ; atomic vol., 10.45 ; sp. heat= 0.2253 between 0-100" ; atomic heat, 6.09" ; less fusible than thecommercial metal, and less easily acted on by alkalis and acids. It isnearly pure tin-white, with no bluish tinge, and has a lustre like thatof tin. It is more malleable and less easily hardened by hammeringthan ordinary aluminium. E. W. P.Decomposition of Phosphate by Potassium Sulphate atHigh Temperatures. By €3. GRANDEAU (Comnpt. rend., 95, gal--922).-Debray (BUZZ. SOC. Chim., 3, 251) has shown that on heahingto a high temperature aluminium phosphate with excess of an alka-line sulphate, an alkaline phosphate and crystallised aluminium areobtained.This reaction has been used by Derdme (Compt. r e d , 89,92.5, and this Journal, 38, 286) for the separation of phosphoric acidfrom iron and aluminium. To determine the conditions of the re-action, a mixtiire of aluminium phosphate and potassium sulphntewas heated for several hours in a platinum crucible. At a hightemperature, not only is alumina formed, but also a crystalline doublephosphate of aluminium and potassium. At a still higher tempe-rat me, the quantity of alumina increases, but even on very vigorousheating it is impossible to completely decompose the double phos152 ABSTRACTS OF CHEMICAL PAPERS.phate. Similar results were obtained by subst,ituting phosphates ofglucinum, cerium, and didymium for aluniinium phosphate.Butwhen phosphates of calcium, magnesium, &c., were used, the doablephosphate alone was formed under the conditions of the experiment ;whilst with nickel and cobalt; phosphates results similar to those withaluminium phosphates were obtained. With chromium and uraniumphosphates, the final products are potassium chromate and uranate.The investigation is being continued.Determination of the Equivalent of Thorium. By L. I?.NILSON (Compt. j-end., 95, 729--730).-As a mean of ten determiua-tions, the author finds 58.10 to be the equivalent of thorium, that ofoxygen being 8, and of sulphur 16. H e makes the atomic weight,therefore, to be 232.36. These results were obtained by calcining twodifferent specimens of the sulphate, a aud b.Specimen b was obtainedfrom the mother-liquors of a. The first six determinations were madeon specimen a, which contained nine molecules of water. I n thesesix experiments the author used the hydrated salt, because the dehy-drated substance was found to be extremely hygroscopic. In theother four experiments this was impossible, because specimen b (tliecrystals of which differed from those of specimen a ) contained onlyeight molecules of water, and absorbed water during the process ofweighing. I n the latter four experiments, therefore, the anhydroussulphate was used. The two specimens gave practically identicalresults.L. T. 0's.Sulphate a.Water. SO3. Thoa. Equiv. At. Wt.Mean of six experiments 27.573 27.336 45.091 58.11 232.43Sulphate b.Mean of four experiments - 37.703 62.297 58.09 232.30The author concludes by drawing attention to the wide diwrepanciesin the values of the atomic weight as determined by other chemists.E.H. R.Metallic Thorium. By L. F. NILSON (Conyf. rend., 95, 727-729).-The author obtains metallic thorium by heating with sodiumi n an iron crucible a mixture of the anhydrous double chloride ofthorium and potassium with sodium chloride. After treatment of theresidue with water, metallic thorium remains as a heavy greyishbrilliant powder. Examined under the microscope, the powder isseen to con\ist of minute crystals, more or less brilliant and united ingroups. The metal is brittle and almost infusible. The powderassumes a metallic lustre under pressure, is unalterable in air up to120", takes fire in air or ox)-gen below a red heat, and burns withdazzling brilliancy, leaving a perfectly white oxide.It takes firewhen heated with chlorine, iodine, bromine, and sulphur. It is notattacked either by hot or by cold water. Dilute sulphuric acid causesa feeble evolution of hydrogen in the cold, becoming more rapid onthe application of heat, but the metal is attacked slowly; hot con-centrated sulphuric acid also acts but slowly, disengaging sulphurouINORGANIC CHEMISTRY. 153anhydride. Nitric acid, whether hot or cold, strong or dilute, exertsno sensible action. Dilute hydrochloric acid dissolves the metal slowlyeven when heated, but concentrated acid attacks it very easily.Aquaregia acts like hydrochloric acid. The metalobtained by hhe author behaves, therefore, exactly like that obtainedby Berzelius. The mean sp. gr. is nearly 11; this is much highert,han that found by Chydenius (7.657 to 7.795) : hence the specimenobtained by the latter chemist must have contained much impurity,probably derived from the glass tube in which it was preptred. Thedensities of two different specimens of the oxide were 10.2207 and20.2198 respectively. These numbers are again much higher thanthose obtained by Berzelius, Damour, and Chydenius (9.402, 9.366,9.288). Admitting that the metal is quadrivalent, the atomic volumeis 21.1. This number coincides with the atomic volume of zirconium(21*7), cerium (21*1), lanthanum (22.6), and didymium (21.5) ; andthis fact serves to confirm the author’s opinion that the rare earth-metals form a series of quadrivalent elements.Magnesia Alba.By R. KRAUT (Arch. Pharm. [ 3 ] , 20, 180-187).-In this criticism of Beckurts’ paper on the composition of magnesiaaZbu (this vol., p. 13), the author shows that analytical errors have creptin, as no direct estimation of the water lost by heating was made,&c.; the formula proposed by Beckurts therefore is incorrect, andthe original formula 5Mg04C02,Hz0, as proposed by Kraut, is theright one; also by boiling for some time, the composition may bealtered to 4Mg0,3COZ,6HzO, but never to 7Mg0,5C02.Separation of Gallium. By L. DE BOISBAUDRAN (Cowzpt. Tend.,95, 410-413 ; 503-506.See also Abstr., 1882, 897, 1323).--FromIndium .-Precipit#ation of the gallium by potassium ferrocyanide, inpresence of hydrochloric acid, is to be recommended only when it isrequired to separate a little indium, together with other metals, suchas aluminium and chromium. The following is the only trustworthymethod :-The moderately concentrated solution is boiled for someminutes with a slight excess of potassium hydroxide ; the precipitatedindium hydroxide retains small quantities o€ gallium, which may beremoved by a repetition of the process. The alkaline solutioas containonly very slight traces of indium ; to remove these, hydrochloric acidis added in slight excess, and the gallium and indium are precipitatedtogether by boiling with an excess of ammonia, or better, by means ofcupric hydroxide.The gallium and indium chlorides are then convertedinto sulphates; the slightly acid solution mixed with a quantity ofammonium sulphate rather more than sufficient to convert the galliuminto alum is evaporated to small bulk, and, after cooling, mixed withfour or five times its volume of alcohol of 70 per cent. Gallium alumis thus thrown down as a crystalline powder, which is washed once ortwice with alcohol, dissolved in warm water containing a minute quan-tity of sulphuric acid, and reprecipitated. By several repetitions oftlhis process, the gallium is obtained in the form of alum, free fromindium. The alcoliolic washings, which contain small quantities ofgallium and indium, are evaporated to small bulk, the metals pre-Alkalis ha.ve no action.E.H. R.E. W. P.VOL. XLIV. 154 ABSTRACTS OF CHEXICAL PAPERS.cipitated by boiling with ammonia or by means of cupric hydroxide,the precipitate dissolved in hydrochloric acid, and the solution boiledwith a slight excess of potassium hydroxide; a small quantity ofindium hydroxide is thus obtained free from gallium. The galliuinremaining in solution may be separated as alum. Usually the indiumdissolved by tlie potash is removed by four crystallisations of theammonium-gallium alum ; but if the gallium hydroxide contains morethan 4 per cent. of indium hydroxide, seven or eight crystallisationsare necessary.Froin CadnLiurrz. - In presence of much free hydrochloric acid,cadmium is not completely precipitated by hydrogen sulphide, whilst ifthe solut'ion is but feebly acid, the cadmium sulphide contains gallium.The somewhat acid solution is treated with hydrogen sulphide, theprecipihate redissolved in hydrochloric acid, the solution diluted, andagain treated with hydrogen sulphide.By two or three repetitionsof the process, the greater part of the dadmium is obtained as sulphidefree from gallium. The filtrates which contain the gallium, mixedwith a little cadmium, are evaporated to expel excess of acid, dilutledwith water, and saturated with hydrogen sulphide. The cadmiumsulphide thus thrown down is reprecipitated two o r three times.Excess of boiling potassium hydroxide precipitates cadmium oxide,and dissolves gallium hydroxide ; the cadmium oxide is redissolvedand again precipitated, in order to separate the last traces of gallium.If the amount of cadmium is large, this process must be repeatedfour or five times.The alkaline solution which contains gallium anda small quantity of cadmium is slightly acidified wjth hydrochloricacid, and the gallium precipitated by means of cupric hydroxide, thefiltrate is mixed with ammonium acetate, and treated with hydrogensulphide, which throws down copper and cadmium : this precipitateis dissolved in aqua regia, evaporated with hydrochloric acid, andhydrogen sulphide is passed into the strongly acid solution ; coppersulphide is thus precipitated, whilst cadmium remains in solution.The following methods are more rapid:-(1.) The solution, whichmust contain a sufficient quantity of ammonium chloride, is boiled withexcess of ammonia: cadmium then remains in solution, and galliumhydroxide is precipitated ; this precipitate is redissolved and againprecipitated, in order to remove the last traces of cadmium.(2.) Gal-lium is precipitated by means of potassium ferrocyanide in a solutionwhich contains at least one-third of its volume of strong hydrochloricacid ; the cadmium ferrocyanide remains in solution. (3.) Cuprichydroxide precipitates gallium on gently warming ; the precipitateretains small quantities of cadmium, which may be removed by arepetition of the process. (4.) When it is necessary to remove ironas well as cadmium, the warm solution is reduced by metallic copperand then mixed with a slight excess of cuprous oxide: the pre-cipitated gallium hydroxide contains traces of cadmium, which maybe removed by reprecipitation.The reactions with cupric hydroxide, and with metallic copper andcuprous oxide, are the most satisfactory.Fronz Ur.cr.nium.-(l.) The boiling slightly acid solution of thechloride is treated with cupric hydroxide ; the precipitate is then disINORGANIC CHEMISTRY.155solved in hydrochloric acid, diluted, and again precipitated with cuprichydroxide, the treatment being repeated four or five times. (2.) Ifit is required to separate iron a t the same time, the solution is reducedwith metallic copper, and then boiled with excess of cuprous oxide;tbe precipitate is redissolved and the treatment repeated about fourtimes.Neither of these methods is affected by the presence of con-siderable quantities of alkaline salts. (3.) The slightly acid solutionof the chloride is mixed wit11 an excess of acid ammonium acetate,zinc chloride free from gallium added, and the liquid is treated withhydrogen sulphide : the zinc sulphide formed carries down the gallium,whilst the uranium remains in solution. The precipitate is difficult towash and must be redissolved in hydrochloric acid, and again preci-pitated in presence of an acetate. The zinc and gallium are separatedby the method previously described. (4.) The uranium is preci-pitated in the form of alkaline uranate by adding a slight excess ofpotassium hydroxide, the precipitate dissolved in hydrochloric acid,and again precipitated.To remove traces of uranium from the fil-trate, the latter is slightly acidified with hydrochloric acid, and boiledwith cupric hydroxide. When the potassium hydroxide contains car-bonate, the quantity of uranium in the filtrate is increased.From Lead.-(1.) The slightly acid solution of the chloride is boiledwith cupric hydroxide, the last trace of lead being removed by a secondprecipitation. The reagents must be free from sulphuric acid. Thismethod is very accurate, and may be used to separate gallium sulphat,efrom the minute quantities of lead which remain in solution afterprecipitation of lead as sulphate. (2.) The solution of chloride o rsulphate is boiled with metallic copper and then with cuprous oxide,traces of lead being removed by a second precipitation.If a solutionof the chlorides is used, the presence of sulphuric acid in the reagentsmust be avoided. (3.) The moderately acid solution is treated withhydrogen sulphide, the filtrate evaporated almost to dryness to expelfree acid, diluted with water, and again treated with hydrogen sul-phide. If sulphuric acid is present, i t should be partially neutralisedwith ammonia. To extract the gallium retained by the lead sulphide,the latter is treated with strong hydrochloric acid, alcohol is added, theliquid is filtered, and the filtrate, after evaporation to expel water andalcohol, is diluted, and saturated with hydrogen sulphide. (4.) Thegallium is then precipitated as ferrocyanide by means of potassiumferrocyanide in a solution containing one-third or one-fourth its volumeof stroug hydrochloric acid.A second precipitation is sometimesnecessary in order to remove the last traces of lead. (5.) The solu-tion is mixed with sulphuric acid, and two volumes of alcohol of 90"added; the precipitated lead sulphate, after being washed with alcoholacidified with sulphuric acid, is suspended in dilute hydrochloric acidand treated with hydrogen sulphide; and the filtrate, after beingboiled to expel excess of the gas, is treated with cupric hydroxide toprecipitate the last traces of gallium. The gallium in the alcoholicsolutions is precipitated by cupric hydroxide, after boiling off thealcohol. (6.) The solution is mixed with twice its volume of 90 percent. alcohol ; a slight excess of hydrochloric acid is added, and theprecipitated lead chloride is washed with acidulated alcohol, whereby itnz 156 ABSTRACTS OF CEEMICAL PAPERS.is obtained free from gallium.The filtrate is evaporated to smallbulk, the nitric acid removed, and the liquid treated either with hydro-gen sulphide, with cupric hydroxide, or with metallic copper andcuprons oxide. C. H. B.Separation of Gallium. By L. DE BOISBAUDRAN (COW&re12d., 95, 703-706) .--Xepayation from Tin.-Sulphide of tin pre-cipitated from a hydrochloric acid solution containing tin andgallium, retains none of the latter metal. On adding hydrochloricacid in excess to a solution of the sulphides of tin and gallium in analkaline sulphide, sulphide of tin free from gallium is thrown down.Salts of manganese added to a solution of the mixed sulphides in ana1 kaline sulphide give a precipitate of manganese snlphide, whichcontains gallium: this makes it possible to extract the latter metalfrom large quantities of sulphide of tin.The author draws atten-tion to one or two points, of which notice must be taken in analysingmixtures containing gallium. A solution containing even a con-siderable amount of gallium is not precipitated by potassium ferro-cyanide if a large amount of stannic chloride is present; so that tinmust be separated before attempting to estimate gallium by ferro-cyanide. Tin and gallium, when alloyed, cannot be completelyseparated by nitric acid, because the metastannic acid formed retainssensible quantities of gallium, even after prolonged washing withnitric acid.It is difficult to obtain a complete separation of galliumand tin by precipitating the latter metal with zinc, because in a solu-tion strongly acid the tin is not entirely thrown down, and in a nearlyneutral solution a certain quantity of gallium becomes insoluble.Finally, tin dioxide, precipitated by boiling with sulphuric acid,retains much gallium.Xeparation from Antimony.-Gallium may be separated from anti-mony by sulphuretted hydrogen, or by addition of an acid to a solutionof the sulphide in an alkaline solution, just as described in the case oftin, except that in the case of the solution in the alkaline sulphide, itis advisable to repeat the process.Potassium ferrocyanide precipitatesgallium from a solution containing antimony, but the precipitatecontains traces of the latter metal, which must be removed by dis-solving it in potash and reprecipitating by addition of a large excess ofhydrochloric acid and a few drops of ferrocyanide. Salts of man-ganese can be used to separate traces of gallium from antimony, justas in the case of tin. Precipitation of the antimony by zinc does notanswer well. E. H. R.Compouhds of Tin Disulphide and Diselenide.Compt. rend., 9 5, 641- 644) .---Potassiunz thiostannafe,By A. DITTESnS,,K2S,3H,0,forms transparent colourless or very sIightly yellow prisms, very solu-ble in water, but decomposed by a large quantity of that liquid, withprecipit,ation of hydrated stannic sulphide. It is obtained by dissolv-i n g stannous sulphide in a solution of potassium polysulphide, ormore easily by boiling a concentrat,ed solution of potassium monoINORQANIC CBERIISTRY.157sulphide with the theoretical amount of sulphur and a slight excess oftin, and evaporating the clear yellow solution by boiling or in avacuum. Potassium seZen,iothiostarLi~,ate, SnSe2,K2S,3H20, is obtainedby substituting selenium for sulphur in the preceding operation. Itforms yellow octohedrons, very soluble in water, with formation of arose or red solution, according to the degree of concentration. Bokhthe solution and the crystals alter when exposed to air, black crystal-line selenium being liberated.SnSez,K2Se,3Hz0,is obtained by saturating a solution of potassium selenide with tindiselenide and evaporating in a vacuum.It forms crystals whichalter rapidly when exposed to air. Sodium thiostnnnate and sodiumseleniostannate are obtained in the same way as the correspondingpotassium compounds, and have similar properties. Ammomiurn thio-stannate, 3Sn Sp, (NHd)zS,6H,0, is obtained by heating sheet tin witha solution of ammonium polysalphides, and evaporating the clearyellow liquid in a vacuum over potassium hydroxide and sulphuricacid. It forms yellow plates, which are decomposed by water withsepnration of hydrated stannic sulphide. The crystals a1 ter quicklyeven in a vacuum, losing water and acquiring a superficial violet tint.When gently heated, t$hey lose water, ammonium sulphydrate, andsulphur, a residue of tin salphide being left.Ammunium seleniotlzio-stnnnate, 3SnSe2,(NH4),S,3H,0, is obtained by treating an excess ofhydrated tin diselenide with a concentrated solution of ammoniumsulphydrate in the cold, filtering, and evaporating the red filtrate in avacuum over potassium hydroxide and sulphuric acid. It formsyellowish-red plates, less stable than the preceding compound. Thecrystals are decomposed by water, with separation of red flakes of tindiselenide.Tellurium dissolves in boiling concentrated solutions of the alkalinesulphides, but yields no compounds with tin analogous to thosealready described. Tellurium is deposited in crystals when the solu-tion cools.Barium tkiostannate, SnSz,BaS,8H20, obtained by dissolving tinin a boiling solution of barium polysulphides and evaporating the solu-tion in a vacuum, forms transparent citron-yellow crystals, soluble incold water without decomposition. From this solution dilute acidsimmediately precipitate yellow fitannic sulphide.Strontium thio-stannate, SnS2,SrS, 12Hz0, produced in a similar manner, forms bulky,transparent, colourless prisms, soluble in cold water without decom-position. Ca Zeium tlAmkmanate, SnS2,2CaS, 14H20, also obtained ina similar manner, forms transparent citron- yellow crystals, soluble incold water without decomposition.Potassium se Ze?aiostunnate,C. H. B.Preparation of Lead Dioxide. By A. FEHRMANN (Bey., 15, 1882).-A concentrated solution (60-70" C.) of lead chloride is treated withsolution of chloride of lime until a filtered sample does not showfurther separation of the dioxide ; the latter is then filtered off andwashed out of contact with air. Lead dioxide so prepared is quitepure and nearly black, and keeps best in the moist state. Whe158 ABSTRACTS O F CHEMICAL PAPERS.prepared from sugar of lead it is not so cheap, and liable to undergodecomposition from the impurities of the lead acetate.Barium Compounds of Bismuth Peroxide. By I. MESCHTCHER-SKY (Journ. Russ. Chem. SOC., 1886, 280--281).-0n fusing a mixtureof bismuth trioxide, baryta, and potassium chlorate, a black mass isobtained, which, when washed with water, begins to decompose, withevolution of oxygen. The black or reddish-brown residue remainingafter the extraction of soluble salts by water consists of compounds ofbismuth peroxide with barium, and decomposes hydrochloric acid withevolution of chlorine. Analogous compounds with calcium or magne-sium could not be obtained. If the above compound has been wellwashed with water, it does not lose oxygen under pure water, butdecomposition takes place suddenly in contact with barium peroxide orsolution of potassiiim chlorate. Fusion with potassium nitrate givesrise to compounds containing more oxygen, e.g., one of the followingcomposition : 14Ba0, 5Bi205, S O 2 , 3H20.A Hydrate of Molybdic Acid. By F. PARMENTIER (Compt. rend.,95, 839--841).-The author has examined the yellowish crystallinesubstance which always separates after a time from solutions of alka-line molybdates in nitric acid. He finds that it contains no nitrogen,b u t is a hydrate of molybdic acid, having the composition Mo03,2H20.This substance is not formed in hydrochloric acid solutions of alkalinemolybdates, It is very sparingly soluble in water, a litre dissolvingonly 0.5 gram a t 15". The crystals are efflorescent, and lose half theirwater in a vacuum over sulphuric acid. Heated to 200°, they lose alltheir water, and leave a white residue which sublimes completely onfurther heating. E. H. R.J. K. C.B. B