INORGANIC CHEMISTRY. Inorganic Chemistry. Electrolytic Formation of Hydrogen Peroxide. By FRITZ HABER and S. GRINBERG (Zeit. anorg. Chem., 1898, 18, 37--47).-The authors, on repeating their experiments on the electrolysis of hydrochloric acid (A bstr., 1898, ii, 215 and 365),find that there is no formation of hydrogen peroxide, as previously stated. The test which they employed consisted i n shaking the electrolyte with mercury, and then treating with titanic acid. They now find that the small quantity of hydrogen peroxide pre- viously detected is produced by the action of the air and the finely divided mercury during the filtration. Experiments with platinum and gold electrodes show that if hydrogen peroxide is formed, it is destroyed by a secondary reaction, which takes place according to the equation H,02 + 0 = H,O + 0,, and such a small quantity remains undecomposed that it is not possible to detect it.By EMMANUELE PAT ERN^ and UGO ALVISI (Gccxzettcc, 1898, 28, ii, 18--24).-Those metallic oxalates which are sparingly soluble OF insoluble in water are less soluble in hydrofluoric acid than in solutions acidified with hydrochloric or sul- phuric acid. On adding oxalic acid to a hydrogen fluoride solution of cupric fluoride, cupric oxalate, 2CuC204 + H,O, separates, and only traces of copper remain in solution. Although solutions of manganese chloride, nitrate, or sulphate in the corresponding acid are not precipitated by oxalic acid, yet on adding oxalic acid to a hydrogen fluoride solution of manganese fluoride and warming, a granular, white precipitate of manganic oxalate, MnC,O4,2H20, is obtained, and only traces of manganese remain in solution.Oxalic acid does not give a precipitate with mercuric chloride solution, but throws down mercuric oxalate from a solution of mercuric fluoride in hydrofluoric acid. On heating powdered fluorspar with concentrated oxalic acid solution on the water-bath, the fluorine is slowly but wholly eliminated; the same occurs with magnesium fluoride and the fluorides of the cerite earths, yttria, thoria, &c. ; this fact may be applied in the analysis of incandescent gas-lamp mantles. Concentrated tartaric acid solution decomposes fluorspar completely on the water-bath, although more slowly than oxalic acid. Sulphurous anhydride acts on cupric fluoride, depositing Chevreul’s salt of the composition CU,SO,~CUSO, + 2H,O in minute, red crystals ; the precipitation is, however, incomplete.An acid solution of silver fluoride is precipitated by arsenates, chromates, nitrites, platino- chlorides, and sulphurous acid. E. C. R. Reactions of Metallic Fluorides. W. J. P. VOL. LXXVI. ii. 218 ABSTRACTS OF CHEMICAL PAPERS. Reactions of Fluoro- and Fluoroxy-salts. By EMMANUELE PAT ERN^ and UGO ALVISI (Gazxetta, 1898,28, ii, 24--29).-0n treating, with aqueous oxalic acid, solutions of the silicofluoride, fluoroxyuranate, fluoroxytungstate, fluoroxymolybdate and the hydrogen fluoride of potassium, potassium quadroxalate separates and the corresponding fluoro- or fluoroxy-acid remains in solution ; the silicofluorides of cerium, lanthanum, yttrium, &c., behave similarly, all the fluorine being eliminated from the salt.On heating cryolite with concentrated oxalic acid solution on the water-bath, hydrogen fluoride is evolved, the aluminium fluoride being first decomposed and subsequently the sodium fluoride ; similarly, on passing steam over red-hot cryolite, alumina, hydrogen fluoride, and sodium fluoride are first formed, and in a second stage of the reaction the sodium fluoride is attacked by the water vapour. Triplite is also decomposed by heating with oxalic acid solution. Tartaric acid in aqueous solution also decomposes potassium silico- fluoride and cryolite. Ozone. By ALBERT LADENBURG (Bey., 1898, 31, 2508-2513).- Ozonised oxygen is condensed by means of liquid air and then allowed to partially evaporate, by which the residue is rendered much richer in the less readily volatile ozone.This operation is again repeated and the ozone finally allowed to evaporate; in this way, a gas is obtained which contains 86.16 per cent. by weight of ozone, and has a density of 1.3698 as compared with oxygen, the density being calculated from the rate of effusion determined in Schilling’s apparatus. From these data, it follows that the density of piire ozone would be 1-456 as compared with oxygen, whereas the theoretical density is 1.5. Ozone is not so soluble in water as is usually supposed, since at the normal pressure and ordinary temperature, water only absorbs 0.01 volume or 0*00002 part by weight. An attempt was made to determine the boiling point of ozone by con- densing ozonised oxygen, allowing the oxygen to evaporate, and then as- certaining the temperature at which the residual ozone evaporated.The oxygen volatilised at - 186’ leaving 4-5 C.C. of an almost black opaque liquid, The temperature as indicated by the thermometer then rose to - l2So, at which point the apparatus exploded violently, so that this can only be taken as a lower limit. By RUDOLPH JOH. KNOLL (Ber., 1898,31, 2183--2185).-This alleged compound, S,OCl, (Abstr., 1882, 694), is in reality a mixture of sulphur dichloride, thionyl chloride, and sulphuryl chloride, approximately in the proportions, 17SC1, + 2SOC1, + 5,SOC1,. When it is distilled alone (under 50 mm. pressure), the first fraction of the distillate has not quite the same composition as the last.When it is distilled with sulphur, thionyl and sulphuryl chlorides distil over, and finally sulphur chloride, S,Cl,, which must have been formed by the action of the sulphur on the sulphur dichloride present. C. F. B. By VICTOR LENHER (J. Anzer. Chem. Xoc., 1898, 20, 555--579).--Two series of determinations of the atomic weight of selenium were made by analys- W. J. P. A. H. Ogier’s Sulphur Oxychloride. Atomic Weight and Derivatives of Selenium.INORGANIC CHEMISTRY. 19 ing carefully purified silver selenite, Ag,SeO,, and ammonium seleni- bromide, (NH,),SeBrG. The silver employed in preparing the former was purified by Stas’s method and converted into nitrate ; the selenious anhydride was prepared from pure selenium by means of nitric acid, and was purified by repeated sublimation.On dissolving i t in water and adding the purified silver nitrate, a white precipitate of silver selenite was obtained which crystallised from dilute nitric acid in anhydrous plates having a sp. gr. = 5.9297. The analyses were carried out by expelling the selenium completely in the form of dioxide, by passing hydrogen chloride over the salt contained in a porcelain boat, heated in a combustion tube ; the residue of silver chloride was weighed, and was then reduced by purified hydrogen to metallic silver, and the latter weighed. The average of eleven experiments gives as the atomic weight of selenium, calculated from the silver chloride formed, the value 79.329 (0= 16), the probable error being +OmO09 ; exactly the same value was obtained from the weight of reduced silver in eight of these experiments.Attempts to obtain sodium selenite siifficiently pure to serve as a means of determining the atomic weight of selenium failed. Ammonium selenibromide, however, was readily prepared pure by dissolving ammonium bromide (9 parts) in water, adding selenium (4 parts) and a slight excess of bromine until a clear solution was obtained, and heating on the water-bath until the excess of bromine was expelled ; on slow evaporation, crystals of ammonium seleni- bromide separated, which were purified by repeated crystallisation. Special care was taken t o purify the materials used in preparing the salt. The latter was analysed by precipitating the selenium by hydroxyl- amine hydrochloride, according to Keller’s method (Abstr., 1898, ii, 575), and the mean of eight experiments gave a value 79.285 (0= 16) for the atomic weight, with a probable error +,OmO1l.The general mean of all the author’s experiments is 79.314. Double Bromides of 8elenium.-Although potassium and ammonium selenibromides are easily obtained by adding potassium or ammonium bromide to an aqueous solution of selenium tetrabromide (Muthmann and Schafer, Abstr., 1893, ii, 318), the corresponding sodium and lithium salts do not appear to exist. The selenibromides of rubidium, Rb,SeBr,, and casium, Cs2SeBr6, are somewhat less soluble than the corresponding potassium salt, although closely resembling it in crystalline form ; they are best prepared by adding a slight excess of bromine to a solution of the alkali bromide containing in suspension the theoretical amount of selenium, and evaporating on the water-bath until crystals separate.Corresponding organic salts containing selenium can be prepared by adding the hydrobromide of a base, dissolved in alcohol, to analcoholic solution of selenium dioxide in concentrated hydro- bromic acid. They are all decomposed by water, and prolonged digestion with ether extracts selenium tetrabromide. IWethyZamine selenibvomide, (NH,Me),,H,SeBr,, separates from alcohol containing hydrobromic acid in well defined red crystals; ethylarnine seZenibq*onzide, (NH,Et),,H,SeBr,, formsred, hexagonal prisms. Thedinzethylnmine salt, (NHMe,),,H,SeEr,, and the trimethykmine salt, (NMe,),,H,SeBr6, separate from alcohol in redcrystals, whilst tetvethykunanaoizium selen&oi?aide, ( NEt,),SeBr,, forms 2-220 ABSTRACTS OF CHEMICAL PAPERS.flat, hexagonal plates. On adding the hydrobromides of aniline and diphenylamine to an aqueous solution of selenium tetrabromide, no double salt is formed, but the selenium is almost completely precipitated in the free state. Phenylhydrazine and quinoline act similarly ; pyri- dine hydrobromide, however, gives rise to the salt, (C,H,N),,H,SeBr,, which crystallises from alcohol in deep-red leaflets or prisms, but is de- composed by other solvents. The p'peridiw salt, (C,H,,N),,~,SeBr,, which crystallises from alcohol in red plates, closely resembles the pyridine derivative. Existence of Selenium Monoxide (compare Pierce, Abstr., 1898, ii, 403)-In subliming large quantities of pure selenious anhydride, no odour similar to that attributed by Berzelius to selenium monoxide was noticeable. On heating a mixture of equivalent quantities of sele- nium and its dioxide, either in an open vessel, or in a sealed tube, to the boiling temperature of selenium, no interaction took place, and no gaseous product could be detected. Selenium monobromide does not act on dry silver oxide below 20", but at this temperature a violent action takes place, selenious anhydride alone being formed. From these exDeriments.it is concluded that selenium monoxide does not exist (coipare Chabri6, Ann. Chim. Phys., 1890, [vi], 20, 273). W. A. D. NOTE BY ABSTRAGTOR.-NOrriS (Abstr., 1898, i, 510), has already described the salt, (NHMe,),,H,SeBr,, prepared from dimethylamine, and in addition has obtained the salts, 3NHMe2,HBr,SeBr,2SeBr, ; 2(NHMe,,HBr,),SeBr4 ; 2(NHMe2,HBr2),SeBr, ; and 2( NHMe,,HBr,),NHMe,,H Br,SeBr,.Similar salts were also obtained from trimethylamine. Copper Selenarte. Preparation of Selenic Acid. By R E N ~ METZNER (Compt. rend., 1898, 12'7, 54-57).--8 solution of selenious acid was oxidised by a current of chlorine, the reaction being accom- panied by the development of 30 Cal., and the solution of selenic acid thus obtained was neutralised with piwe cupric oxide. On cooling the liquid, after concentration by evaporation, pale blue prisms of copper selenate, CuSeO, + 5H,O, were deposited. Attempts were made to substitute bromine for chlorine in the preparation of the salt, but it was found that the oxidation of the selenious acid was never com- plete. The solubility of copper selenate varies greatly with the temperature; 1 litre of the saturated solution was found to contain 257 grams of the salt at 15", 346 grams at 35", and 435 grams a t 55".A t about 70°, the solution undergoes decomposition, with formation of it green, crystalline deposit which is seen under the microscope to consist of small, monoclinic prisms. This compound was first obtained, but not analysed, by Mitscherlich ; the author's analyses show that i t has the composition 2CuSe04,Cu0 + 5H,O. When crystallised from a solution containing a large excess of selenic acid, copper selenate forms microscopic, transparent, tabular crystals of the composition CuSe04+2H,0.The crystals lose water on exposure to a dry atmosphere, and when dried at 100" only one molecule of water is retained. The heat of formation of copper selenate (18.12 Cal.) was deduced from the heat developed (13.06 Gal.) on precipitating aINORUANIC CHEMISTRY. 21 normal solution of the salt with the equivalent amount of potash. The heat of dissolution is - 2-66 Cal. Selenic acid was obtained in a very pure state by the electrolysis of a saturated solution of copper selenate with a current of 5 amperes a t 2-3 volts. N. L. Decomposition of Nitric Acid by Heat a t Moderate Tempera- tures. By MARCELLIN P. E. BERTHELOT (Compt. rend., 1898, 127, 83--88).--Small quantities of purenitric acid were introduced into tubes previously made vacuous and having a volume about 20 times that of the liquid, and the tubes were then kept in the dark at the ordinary temperature for several weeks ; the nitric acid remained unaltered.When, however, similar tubes are heated a t loo', also in the dark, the nitric acid decomposes into nitric peroxide, oxygen, and water, and the decomposition at first increases with the time, but the rate of increase gradually falls. The decomposition is always incomplete and is limited chiefly by the water produced. Nitric acid of sp. gr. 1.333 undergoes practically no change at looo under similar conditions. The decomposition can scarcely be regarded as reversible, since the oxygen will combine very slowly with any nitrous acid that may be formed by the action of the nitric peroxide on the water.Thedecom- position of nitric acid into nitric peroxide, oxygen, and water at 100' would absorb about - 6.5 Cal. per molecule of acid. The decomposition of nitric anhydride absorbs much less, hence the instability of this compound. On the other hand, the heat of formation of hydrated nitric acid is much higher than that of the anhydrous acid, hence the greater stability of the former. Action of Free Hydrogen on Nitric Acid. By MARCELLIN P. E. BERTHELOT (Compt, rend., 1898,127,27-29).-Sealed tubes containing known quantities of hydrogen and concentrated nitric acid were exposed to direct sunlight for two weeks, kept in the dark during the same period, and heated a t 100' for 1 to 5 hours. I n every case, the original volume of hydrogen employed was recovered on examining the contents of the tubes, even when the experimental conditions had been such that the nitric acid itself was decomposed, with liberation of oxygen.This inactivity of hydrogen towarda nitric acid is in striking contrast with its behaviour with concentrated sulphuric acid, which is acted on at the ordinary temperature with formation of sulphurous acid. The liberation of oxygen from pure nitric acid takes place a t 100' and also, under the influence of light, in the cold ; it does not take place in the dark a t the ordinary temperature. The author's observations N. L. Action of Dilute Nitric, Sulphuric, Hydrochloric and Phos- phoric Acids on Nitrates in the Presence of Ether. By CHARLES TANRET (BztZZ. Soc. Chim., 1897, [iii], 17, 497--503).-It has pre- viously (Abstr., 1897, ii, 255) been shown that the presence of nitrates raises the coefficient partition of dilute nitric acid between ether and water.This property affords a basis for a method of extracting free nitric acid from solutions of nitrates by the aid of ether. C. H. B. on this point will be published hereafter.22 ABSTRACTS OF CHEMICAL PAPERS. The reaction between dilute sulphuric acid and an excess of potassium nitrate is represented as follows : H2S0, + 2KN0, = HNO, + KNO, + KHSO,. If the nitric acid thus formed is removed by ether, then the acid sulphate tends to dissociate under the influence of the water into sulphuric acid and the normal sulphate. The sulphuric acid will then act on a further amount of potassium nitrate according to the above equation, until the whole of the sulphuric acid has been converted into normal sulphate, as if the reaction had taken place according to the equation H,SO, + 2KN0, = K,SO, + 2HN0,.This has been proved experimentally by taking 20 C.C. of water containing 0.20 gram of sulphuric acid, dissolving in this 5 grams of potassium nitrate, and extracting with 200 C.C. of ether, the ex- traction being repeated six times. Hydrochloric acid reacts in the same manner as sulphuric acid. Phosphoric acid reacts according t o the equation H,PO, + KNO, = I’INO, + KH2P0,. Nitric acid acting on normal sulphates gives acid sulphates; the acid sulphate does not sensibly dissociate,. yielding free sulphuric acid. The action between nitric acid and chlorides is not appreciable.J. J. S. Homogeneity of Helium. By WILLIAM RAMSAY and MORRIS W. TRAVERS (PYOC. Boy. Xoc., 1898,52,3 16-324).-The gas was separated into six fractions by diffusion through a piece of pipe stem. Fraction No. 1 was then pumped into the diffusion vessel, one half of it was diffused and transferred to vessel No 1 ; fraction No, 2 was then added, and one-third of the mixture diffused and transferred to vessel No. 1 ; fraction No. 3 was then added, and one half of the whole diffused and transferred to vessel No. 2 ; fraction No, 4 added and one half diffused and transferred to vessel No. 3, and so on. After four such complete fractionations in the case of air, the extreme fractions contained 17-37 and 22.03 per cent. of oxygen respectively. In the case of nitrogen, prepared from solutions of ammonium chloride and sodium nitrite, with some copper sulphate, thirty fractionations produced no alteration in density.Repeated fractionations of samples of helium from samarskite and cleveite resulted in the separation of helium with density 1.98 and refractivity 0.1238 as the lightest fraction, and a very little nearly pure argon as the heaviest fraction. The light fraction was apparently pure helium, as further diffusion did not alter its density. “ It appears, therefore, tbat helium contains no unknown gas, nor is it possible to separate it by diffusion into any two kinds of gas; all that can be said is that most minerals which evolve helium also evolve argon in small quantity.” The authors had hoped to find an element with density = 10 and atomic weight = 20 ; they still regard the existence of such an element as probable, for it would form with He = 4 and A = 40 a triad like F= 19, Cl= 35.5, Mn= 55 and many similar triads occurring in the groups of the periodic table.Conversion of Potassium Iodide and Bromide into Potassium Chloride. By FRIEDRICH W. KUSTER (Zeit. anorg. Chem., 1898, 18, 77 - €32)-Potassium iodide is easily and completely con- C. F. B.INORGANIC CHEMISTRY, 23 verted into potassium chloride by heating it in a porcelain crucible in a current of chlorine, Potassium bromide, on the other hand, cannot be completely converted into chloride by means of a current of dry chorine unless it is heated to such a high temperature that potassium chloride begins to volatilise. I n the presence of water, however, the conversion into chloride is complete at moderate temperatures. The potassium bromide (2.49 grams) is treated in a small Erlenmeyer flask with 1 C.C.of water and a drop of hydrochloric acid and then heated in a brisk current of chlorine. The flask is placed on an asbestos plate with another asbestos plate 2 C.C. below the first and under this a small burner. After 1-14 hours heating below the boiling point, the water is evaporated off and finally the asbestos plate on which the flask rests is heated to redness for a short time, and the operation repeated until a constant weight is obtained. By H. C. HAEN (J. Amer. Chem. Xoc., 1898,20, 621-630).-This is an elaborate investigation as to the best way of accurately determining the sp.gr. of sodium chloride solutions. To be of any real value, the sp. gr. a t 15.08O should be exact to the fourth place of decimals. In this case, if X = the sp. gr., the percentage of sodium chloride will be 60,209,585 - 626,853,lS + 1067,352,66782 - 633,92Xs + 133,333,333S4. A main factor in determining the sp. gr. is the knowledge of the sp. gr. of the air in the balance case, which depends on the pressure, temperature, moisture, and the amount of carbonic anhydride. For further particulars, the original paper should be consulted, the results Action of Sodium Metarsenite on Metallic Salts, By C. REICHARD (Ber., 1898, 31, 2163-2171).-When sodium metarsenite, Na2As204, was added to excess of a solution of a metallic salt, free E. C. R. Speciflc Gravity of Sodium Chloride Solutions. being set forth in a very comprehensive table.L. DE E. Composition. Metallic salt used. Ni(N03)2 Pb(NOa12 ZnSO, SnCI, Properties. Bright green, amorphous powder. Heavy, white powder. Crystallises from ammonia in white needles. Yellowish-white ; decoiriposed by acids and alkalis Amethyst-coloured mass, White substance. Green, amorphous powder. Greenish-white substance, turning rusty in the air. White, turning pink to brown in the air. White mass, turning yellow and decomposing in Yellowish-white mass. Yellowish substance, decomposed by caustic soda with separation of metallic arsenic. daylight. with separation of metallic silver.24 ABSTRACTS OF CHEMICAL PAPERS. acid was always liberated, and the precipitate was in 4 cases (enumerated first in the table) an orthoarsenite, in 2 (the next two) a pyroarsenite, but in no case was it a metarsenite. The substances prepared are described in the table (p.23). Action of Hydrogen on Silver Sulphide. By H. P~LABON (Compt. rend., 1898, 126, 1864-1 866).-Hydrogen acts on silver sulphide in sealed tubes above 250', the proportion of hydrogen sulphide formed at first increasing with the time but eventually becoming con- stant. Conversely, in a tube containing silver and hydrogen sulphide, the quantity of the latter gradually diminishes until it reaches a limit. A t any given temperature above 350°, the limit is the same, whether the initial system contained hydrogen sulphide and silver, or silver sulphide and hydrogen. The ratio, p, of the partial pressure of the hydrogen sulphide to the total pressure of the mixture diminishes as the temperature rises and the curve that representsit as a function of the temperature approaches the axis of the abscissze as the tempera- ture increases.Between 360' and 700°, the curve is identical with a straight line passing through the points p = 0.21, t = 360', and p = 0.16, t = 700". Whatever the initial system, equilibrium is reached more quickly the higher the temperature; at 36O0, about 160 hours is necessary, whilst a t 580° a few moments suffice. At a given temperature, the limit value of p is independent of the physical con- dition of the silver or silver sulphide, and, moreover, is the same if the initial system consisted of silver, hydrogen, and sulphur. The silver liberated from the silver sulphide forms filiform masses only when the temperature is below 580°, and the best specimens are obtained by C.F. B. h e a h g crystallised silver sulphide and hydrogen in sealed tubes a t 440'. C. H. B. Heat of Formation of Lithium Carbide. By ANTOINE GUNTZ (Compt. rend., 1898, 126, 1866--1868).-The action of water on lithium carbide, C,Li,, develops + 37-10 Cal., and hence C, (diamond) + Li, sol. = C,Li, (sol.) develops + 11 93 Gal., a value which is much higher than the corresponding values for sodium or calcium, and explains the formation of lithium carbide under such varied conditions. When the carbide is prepared by the direct action of lithium on carbon, the mixture must be placed in an iron dish in a hard glass tube enclosed in a glazed porcelain tube, and the tubes must be made vacuous, because lithium readily combines with nitrogen.The temperature must not exceed a dull red heat, otherwise the carbide dissociates. Even the diamond is attacked by lithium a t this temperature. The carbide cannot be obtained by heating carbon with lithium carbonate, because the latter volatilises before it dissociates. When the carbide is added to fused lithium chloride, lithium subchloride and carbon are formed, but a t a high temperature the subchloride dissociates into the normal chloride and lithium, and the latter attacks the carbon, and these changes go on until a condition of equilibrium is established. These observations explain why a carbon cathode cannot be used for the isolation of lithium by electrolysis of the fused chloride.C. H. B.INOHGANIC CHEMISTRY, 25 Calcium Hydride. By HENRI MOISSAN (Compt . rend., 1398, 127, 29--34).-Calcium hydride is obtained by heating crystallised calcium (Abstr., 1898, ii, 578), contained in a nickel boat, to dull redness in an atmosphere of dry hydrogen. Comparison of the weight of metal employed with the weight of hydride obtained, and measurement of the volume of hydrogen evolved on treating the substance with water, show that the hydride has the composition CaH,. Obtained as above, calcium hydride forms a white, fused mass of crystalline fracture, which is shown by microscopic examination to consist of slender, transparent plates; it has a sp. gr. = 1.7. When heated to 600' in a vacuum, no appreciable dissociation occurs ; nor is the hydride affected by heating in hydrogen at the melting point of glass.It is decom- posed by the halogens at a dull red heat, with incandescence. When heated to redness in air or oxygen, it burns brilliantly, and sufficient heat is evolved to cause fusion and crystallisation of the calcium oxide formed, Calcium hydride is decomposed by heating in sulphur or phosphorus vapour, but no action was observed with selenium at the melting point of glass, or with nitrogen, silicon, and boron. When heated a t 700-80O0 with finely-divided carbon, calcium hydride is partially decomposed, with production of calcium carbide. Metallic fluorides, sodium chloride, and silver iodide are decomposed when heated with calcium hydride, but potassium iodide is not acted on.Chlorates, perchlorates, bromates, or permanganates, and similar oxidising agents, are reduced with explosive violence. Hydrogen sulphide, nitric oxide, and carbonic anhydride aro also decomposed a t a red heat. Calcium hydride is readily decomposed by water and by dilute acids ; concentrated sulphuric and nitric acids, however, have but little action in the cold. Benzene, turpentine, and alkyl chlorides and iodides, when free from water, are without action on calcium hydride; ethylic alcohol slowly attacks it. The vapour of carbon tetrachloride is decomposed, with incaadescence, a t about 400O. N. L. Solubility of Lime in Water at Different Temperatures. By ALEXANDER HERZFELD (Bied. Centr., 1898, 27, 5 7 1 ; from Oesterr. Zeits. Zuckerind., 1897, 1197).-The amounts of water required to dissolve 1 part of CaO at different temperatures are as follows.15" 20" 25" 30" 35" 40" 45" 50" 55" 60" 65" ?Oo 75" 80" 776 813 848 885 924 962 1004 1044 1108 1158 1244 1330 1410 1482 N. H. J. M. Solubility of Lime in Aqueous Solutions of Sodium and Potassium Chloride. By GODFREY L. CABOT (J. Xoc. Chem. Ind., 1897, 16, 417--419).-Curves are given which shorn that the solu- bility of lime in solutions of either sodium or potassium chloride is a maximum for all temperatures when the solution contains about 60 grams of the salt per litre; it is a minimum at any fixed tem- perature when the solution is saturated, the solubility then being much less than in pure water of the same temperature. A solution of sodium chloride dissolves more lime a t all temperatures and con- centrations than a corresponding solution of potassium chloride.I n26 ABSTRACTS OF CHEMICAL PAPERS, all cases, the maximum solubility of lime in the chloride sotutiofi occurs when the temperature is lowest; with solutions of all concen- trations, the solubility decreases regularly as the temperature increases. W. A. D. Formation and Composition of Bleaching Powder. By HUGO DITZ (Chem. Zeit., 1898, 22, 7--9).-The author regards the formation of bleaching powder as taking place in several stages. The first action of chlorine on the slaked lim; is t o give (Ca0,CaCl~OCl+2H20); further action gives (2CaCl*OC1+ CaO,CaCl*OCl+ 4H20) ; yet fur- ther action, (GCaCl*OCI + CaO,CaCl*OCI + 8H,O). In practice, the reaction seems to stop here; theoretically, it might continue inde- finitely, yielding successive members of the series [(Zn - 2)CaCI*OCl+ CaO,CaCl*OCl+ 2nH,O].Most bleaching powders consist of mixtures of the first three members, (n=O, 1, 2), the formulae of which are given above ; but of the numerous published analyses of blenching powders, some are found to correspond very well with these three; three such analyses are quoted below. n= 0. 12=1. n=2. Found. Calc. Found. Calc. Found. Calc. Total CaO ......... 52.12 51.14 44.12 44.01 41.27 41.14 Available C1 ...... 31.44 32-42 41-05 41.85 44.5 45.64 CaO from CaO,CaCI*OCl ... 27.33 25.57 11*80 11.00 5-40 5.14 It is shown that these views allow of a satisfactory explanation of the reactions of bleaching powder with carbonic anhydride, with sul- phurous anhydride, and with acetic acid, and of its behaviour when heated.It is proposed to perform experiments with a view to testing their truth further. c. I?. B. Decomposition of Barium and Calcium Dihydrogen Phos- phates by Water at 100". By GEORGES VIARD (Compt. Tend., 1898, 127, 178-180). -The monobasic phosphates of the alkaline earths are known to undergopartial decomposition by water at the ordinary temperature, with liberation of phosphoric acid and precipita- tion of a dibasic phosphate. The author has studied the decompo- sition of monobarium and monocalcium phosphates by water at loo", and finds the reaction to be similar to that which occurs in the cold, the quantitative results, however, are different. As the weight of monobasic phosphate which is heated with a constant weight of water increases, the ratio of the total phosphoric acid remaining in solution to the combined phosphoric acid also increases, a t first rapidly and then more slowly, until it becomes sensibly constant.The limiting value of this ratio was found to be 2.8 for the barium, and 2-34 for the calcium, salt; in the cold, the values obtained by Joly were 2.0 and 1 *5 respectively. Analysis shows that the precipitate consists only of the dibasic phosphate, unless a saturated solution has been employed, in which case the precipitate is contaminated with undissolved mono- basic phosphate. It is t o be observed that the precipitated dicalcium phosphate is always anhydrous and insoluble in acetic acid, whereas,IN0 RGANIC CHEMISTRY.27 if the decomposition takes place in the cold, the hydrated phosphate, Ca,H,(PO,), + 4H,O, is formed, which is soluble in acetic acid. The composition of the precipitate being once determined, the ratio R, of the total to the combined phosphoric acid may be calculated from the weight of the precipitate. For, if P is the weight of monobasic phosphate employed, iM its molecular weight, p the weight of dibasic phosphate precipitated, m its molecular weight, and q the molecular weight of phosphoric anhydride, then the weights of the latter contained in P and p are Pq/M and pq/m respectively and N. L. Anhydrous Crystalline Magnesium Sulphide. By A. MOURLOT (Compt. q*end., 1898, 127, 180--183).-Amorphous magnesium sul- phide is best prepared by passing a current of hydrogen sulphide over a mixture of sulphur with magnesium filings contained in a carbon boat, which is placed in a porcelain tube heated in a reverberatory furnace.The sulphide is thus obtained as a white, or slightly grey, mass, which analysis shows to have the composition MgS. Another method of preparation consists in passing hydrogen sulphide over anhydrous magnesium sulphate or oxide heated to about 1200' ; in this, however, the action is much slower. When the amorphous sulphide is heated for a few minutes in the electric furnace, it is converted into a globular mass of crystalline fracture, which is shown by analysis to have the same composition as the amorphous sulphide ; the crystalline sulphide may be also prepared by heating, in the electric furnace, a mixture of magnesium chloride with stannous sulphide in molecular proportion.Attempts to prepare i t by the reduction of magnesium sulphate with carbon gave unsatisfac- tory results. The crystalline magnesium sulphide obtained by the methods described above consists of a mass of cubical crystals of sp. gr. = 1.85, which have no action on polarised light, and exhibit two cleavage planes at right angles to each other. It is not acted on by hydrogen at the highest temperature of a reverberatory furnace, but is decom- posed, with incandescence, by chlorine a t about 300°, with the formation of the chlorides of magnesium and sulphur ; bromine and iodine also decompose it a t a dull red heat. The crystalline sulphide is readily oxidised when heated in oxygen, and also by heating with potassium chlorate, potassium nitrate, lead peroxide, and phosphoric anhydride.It is not reduced by heating at a high temperature with phosphorus, boron, silicon, or iron ; sodium, however, decomposes it. It is readily acted on by steam, with formation of magnesium oxide and hydrogen sulphide ; at the ordinary temperature, however, water acts with great difficulty on the crystalline sulphide, whereas the amorphous sulphide is immediately decomposed. Nitric and sul- phuric acids and gaseous hydrogen fluoride and chloride act on the crystalline sulphide a t the ordinary temperature, whilst hydrogen bromide and iodide react a t a dull red heat. It is also readily attacked by phosphorus trichloride and by chromyl chloride; in the28 ABSTRACTS OF CHEMICAL PAPERS.latter case, a greenish substance is produced, the nature of which is being investigated ; it contains both chromium and sulphur. N. L. Formation of Metallic Sulphides by Mechanical Influences. By L ~ O N FRANCK (Bull. Xoc. Chim., 1897, [iii], 17, 504-506).- Spring has shown that sulphides of magnesium, zinc, iron, copper, &c., may be obtained by subjecting intimate mixtures of the metals and sulphur t o a pressure of 6500 atmospheres (Abstr., 1883, 904; 1884, 959), and it has long been known t h a t mercuric sulphide may be obtained by triturating the metal with sulphur, cuprous sulphide by triturating the metal with sulphur under water, and ferrous sulphide in a similar manner with hot water. The author finds that when a mixture of flowers of sulphur and of magnesium powder is rubbed between two sheets of paper, hydrogen sulphide is evolved.A similar reaction occurs with aluminium powder and sulphur, or even when sheet aluminium is rubbed with flowers of sulphur. By G. URBAIN (Conpt. rend., 1898, 12'7, 107--108).-Further investigations have confirmed the utility of the method of fractionating by means of ethyl-sulphates ; it is especially valuable for resolving a complex mixture into groups to which the other methods of fractionation can be applied much more easily than to the original substance, The constituents of crude yttria do not separate with uniform distinctness; i t is easy, for example, to obtain erbium quite free from holmium, but very difficult t o eliminate erbium from the fractions rich in holmium.By com- bining the ethyl-sulphate method with some of the older methods, the author finds that the crude yttria from monazite sands consists chiefly of yttrium of atomic weight 89, and contains terbium with an atomic weight as high as 151.4, but no element with the atomic weight 100 or 97. By ROBERT M. CAVEN and ALFRED HILL (J. Xoc. Chern. hd., 1897, 16, 29-30. Compare Abstr., 1898, ii, 591).-On adding disodium hydrogen phosphate to a n aqueous solution of aluminium sulphate, no precipitate is formed at first, but on boil- ing for a n hour, the greater part of the aluminium is precipitated as phosphate. An excess of ammonium chloride partially precipitates aluminium phosphate from a solution of the latter in aqueous ammonia or caustic alkalis. Cold, dilute acetic acid dissolves aluminium phos- phate, but, on boiling, the latter is precipitated ; ammonium acetate does not produce a precipitate with the cold solution, nor with a solution of the phosphate in hydrochloric acid to which an excess of acetic acid has been added; if, however, only a small quantity of acetic acid is present in the latter case, ammonium acetate gives rise t o a precipitate of aluminium phosphate.On adding dilute acetic acid and ammonium acetate t o a nearly saturated solution of alumi- nium phosphate in aqueous aluminium sulphate, a precipitate is produced, although none is formed when only a small amount of the phosphate is present ; in the latter case, the addition of a little disodium hydrogen phosphate brings about precipitation. Chromium phosphate is gradually precipitated on boiling a solution J.J. S. Yttrium Earths in Monazite Sands. C. H. B. Metallic Phosphates.INORGANIC CHEMISTRY. 29 containing disodium hydrogen phosphate and chromium sulphate ; it is not as easily soluble in aqueous ammonia as aluminium sulphate, but resembles the latter in being precipitated by ammonium chloride from its solution in caustic potash. Chromium phosphate is readily soluble in acetic a.cid, but is precipitated from neutral solutions by ammonium acetate ; like ferric phosphate, it undergoes hydrolysis when washed with water. Traces of chromium and aluminium may be detected in presence of large quantities of ferric phosphate by fusing the mixed phosphates with potassium hydroxide on platinum foil; on adding ammonium chloride to the aqueous extract, aluminium is precipitated as mixed phosphate and hydroxide, and, on filtering, a yellow solution is ob- tained if chromium is present, becoming green when sulphurous acid is added.Cupric phosphate is somewhat soluble in aqueous cupric chloride and cupric sulphate, and undergoes hydrolysis when washed with water ; on boiling w2th water, it is converted into a basic phosphate, Cu3(P0,),,Cu0,H,0, as stated by Steinscheider (Abstr., 1891, 1423), whilst aqueous potash completely hydrolyses i t to cupric oxide. Bismuth phosphate is somewhat soluble in aqueous bismuth chloride, but is not hydrolysed by boiling water, although completely converted into oxide when boiled with caustic alkalis, Lead phosphate is insoluble in aqueous lead nitrate, and is not changed when boiled with water ; it easily dissolves in boiling caustic potash, but less readily in aqueous ammonia.W. A. D. Influence of Silicon on the Heat of Solution of Coke Cast Irons. By EDWARD D. CAMPBELL and WILLIAM E. HARTMAN (J. Amer. Chem. Xoc. 1898, 20, 690-695).-The object of this research was to determine if any thermochemical evidence could be obtained of a change in the condition in which silicon exists in cast iron, this change being due to differences of the temperature at which the iron is made. The solvent was a solution of ammonium copper chloride in the molecular ratio (NH,C1),CuC12 : 50H20, but with the addition of 0.84 per cent. of free hydrochloric acid. When either from a suffi- ciently high temperature of the blast furnace at the time the iron is made, or from the presence of a moderate amount of silicon, probably about one and four-tenths per cent., the carbon is nearly all in the graphitic or “graphitic temper” form; then the heat evolved by theoxid- ation of the silicon, is proportional to the amount of silicon present. When from a low temperature in the furnace accompanied by low silicon, the carbon is largely in the combined form, then the heat rendered sensible is very much diminished owing to the large amount of heat necessary to decompose the compounds of iron and carbon, or possibly compounds of iron, silicon, and carbon, or of carbon and silicon.As the oxidation of one gram of silicon alone develops 3824 Cal., and the results obtained by dissolving cast irons give a maximum of 3303 Cal., it is evident that the compound of silicon with iron must have avery con- siderable heat of formation.When the percentage of silicon is nearly sufficient to correspond with the empirical formula SiFe,, the compound is insoluble in ammonium copper chloride. H. C.30 ABSTRACTS OF CHEMICAL PAPERS. Constitution and Genesis of Iron Sulphates. By RUDOLF SCHARIZER (Zeit. Eryst. Min., 1898, 30, 209--231).-1n an investiga- tion dealing with the genesis of native iron sulphates, the author has made experiments requiring several years For their completion. In this first paper are given the results of experiments on the loss of water, and oxidation of ferrous sulphate. Over sulphuric acid, ferrous sulphate (FeSO, + 7H20) readily loses three molecules of water, 3H,O more are given off, with partial oxida- tion of the ferrous sulphate, at 60-80°, +H,O is lost at 100-300°, whilst the remainder is only given off on ignition.When exposed to air, it effloresces after a long period of time to the end product FeSO, + H20. The products of oxidation of a ferrous sulphate solution depend on the lapse of time and on the degree of dilution of the solution ; ferric sulphate is also formed [lOFeSO, + 5 0 = Fe,SO, + 3Fe2(S04),], and this by its decomposition [3Fe2(S04), + 8H20 = Fe,SO,, + 8H2S0,] introduces further complications. One gram of ferrous sulphate in 50 C.C. of water gives a permanent ferric sulphate solution ; in more concentrated solutions, soluble basic salts are formed, whilst in more dilute solutions there is free sulphuric acid.L. J. 5. Decomposition of Water by Chromous Salts, and their Use for the Absorption of Oxygen. By MARCELLIN P. E. BERTHELOT (Compt. rend,, 1898, 127, 24--27).-Since the oxidation of chromous chloride, with production of the oxychloride, Cr,Cl,O, is accompanied by the evolution of a larger amount of heat (100.4 Cal.) than is pro- duced in the formation of water from its elements, there should be a tendency to the decomposition of water by chromous chloride. The latter reaction does not take place at the ordinary temperature in the case of pure solutions of chromous salts containing no free acid; above 250°, however, or at the ordinary temperature in presence of traces of free hydrochloric acid, decomposition slowly occurs, and hydrogen is evolved.An explanation of the influence of the hydro- chloric acid in this reaction is suggested by a consideration of the properties of the green and violet modifications of chromic chloride, which are formed from chromous chloride with the evolution of 94.6 Cal. and 113.4 Cal. respectively, The oxychloride formed by the oxidation of the chromous chloride is not converted by the hydro- chloric acid into the green chromic chloride, since this reaction would involve the absorption of 5.8 Cal. ; under the influence of time, how- ever, the formation of the violet modification is rendered possible, with the evolution of 13 Cal., and it is the supplementary energy of this reaction which determines the slow decomposition of the water.It follows from the foregoing observations that an acid solution of chromous chloride should not be employed as an absorbent of oxygen in the exact analysis of gaseous mixtures, or in the purification of any By PETR. GI-. MELIKOFF and L. PISSARJEWSKY (Zeit. ccn.org. Chem., 1898, 18, 59--65).-The authors discuss the results which they have obtained in their researches on the peroxides (Abstr., 1898, ii, 161, 165, 219, 292, 332, 337, and 374). They have gas but hydrogen. N. L. Peroxides.INORGANIC CHEMISTRY, 31 shown that the acid peroxides are capable of forming salts with alkali peroxides. The soluble salts, for example, the sodium and lithium salts of peruranic acid, when treated with aluminium hydroxide, are converted into the free acid and hydrogen peroxide; the insoluble salts, for example, the barium salt of peruranic acid, when treated with carbonic anhydride, behave like barium peroxide, and barium carbonate, hydrogen peroxide, and peruranic acid are formed.Acid peroxides of the type RO, have been obtained from elements belonging to six groups, The stability of the salts which they form with alkali peroxides decreases with the atomic weight of the element which forms the acid peroxide. Those peroxides which are strong acids do not form salts with metallic peroxides, but decompose the latter, with formation of hydrogen peroxide. The authors assign to the peroxy-acids and metallic peroxides a constitution of the type of hydrogen peroxide, HO-OH, since they show a simiIar behaviour towards many reagents. When treated with dilute sulphuric acid, they yield hydrogen peroxide; with con- centrated sulphuric acid, many of them yield ozone.The peroxy- acids are decomposed by water in a similar manner to the metallic peroxides ; thus, sodium perborate is partially [decomposed into sodium metaborate and hydrogen peroxide; they also behave in a manner similar to the metallic peroxides when treated with manganese peroxide, whereby oxygen is rapidly evolved in the case of soluble salts, and slowly in that of insoluble salts. The peroxy-acids very easily oxidise alkalis, converting them into peroxides, for example, in the case of peruranic acid according to the equation 3U0, + 4KOH = 2U0, + (K2O2),UO4 + 2H,O. E. C . R. Permolybdates. By PETR. G. MELTKOFF and L. PISSARJEWSKY (Ber., 1898,31, 2448-2451).-The failure of Muthmann and Nagel (Abstr., 1898, ii, 593) to obtain potassium peroxide permolybdate having the properties described by the authors can osly be due to their failure t o reproduce the necessary experimental conditions, and for this reason the authors repeat their description of the method employed by them.To a solution of potassium permolybdate prepared by PQchard's method (Abstr., 1891, 988) are added aqueous solutions of potash and hydrogen peroxide (3 per cent.) in amounts corresponding with the scheme KMoO, + 3KOH + 4H,O, ; the liquid, which has now become dark red, is mixed with alcohol cooled to - 10' to - 1 2 O , insufficient in amount to precipitate potassium peroxide. The flocculent, red precipitate thus produced is separated by means of a filter cooled by ice and salt, washed with alcohol and ether successively, and finally dried on a cooled tile.The salt thus obtained is ready for analysis, and always possesses the same properties ; it evolves oxygen when dissolved in water a t the ordinary temperature, changing colour simultaneously, and i t is exploded by friction, or by the heat spontaneously developed on exposure to air; it is not hygroscopic as mas the substance obtained by Muthmann and Nagel, and i t is probable that these experimenters were dealing with an impure specimen containing potassium peroxide.32 ABSTRACTS OF CHEMICAL PAPERS. The suggestion made by Muthmann and Nagel, that the foregoing substance contained some hydrogen peroxide, is untenable, as its pro- perties are not sensibly different if excess of hydrogen peroxide be employed in its preparation, and when it is reprecipitated from a solution in alkaline hydrogen peroxide its properties remain unaltered.It is, therefore, a chemical individual. The authors are unable to accept the view that the molybdates can combine with a molecular proportion of oxygen at low temperatures, and believe that there is much evidence to show that the I' per-" acids form salt-like compounds with the metallic peroxides. A. L. Action of Hydrogen on Potassium Paratungstate. By L. A. HALLOPEAU (Comdpt. rend., 1898, 127, 57-58).-When potassium paratungstate is heated to dull redness in a current of hydrogen, a mixture of tungsten dioxide with the blue oxide of tungsten is ob- tained.A t higher temperatures, a compound of the composition K,OIWO, + WO,,WO, is also produced, which crystallises in small, reddish-violet prisms having a coppery lustre. This substance, which appears to be identical with the compounds obtained by Laurent and by Wohler, may be purified by prolonged washing with boiling water, concentrated hydrochloric acid, and potassium carbonate solution. A t a bright red heat, it nndergoes further reduction by hydrogen, with Production of Tungsten Blue by the Reduction of Tungsten in Porcelain Furnaces, By ALBERT GRANGER (Comnpt. rend., 1898, 127, 106--107).-When a mixture of barium and sodium tetra- tungstates, RI',O, WO,, is used as a glaze on porcelain and is heated in a reducing flame at about 1250°, it yields a blue colour varying from pale blue to indigo. The t i n t depends on the proportion of the two salts and the quantity of the glaze used, and can also be modified by adding borax or phosphates.The blue colour is most probably due to the formation of the oxide W,O, in the conditions specified. formation of metallic tungsten. N. L. C. H. B. Lead-antimony, Tin-antimony, Tin-arsenic, and Tin-phos- phorus Alloys. By JOHN E. STEAD (J. SOC. Chem., Ind., 1897, 16, 300-208 and 309).-When alloys of lead and antimony containing from 1-12.66 per cent. of the latter, are melted and allowed to solidify, a perfectly homogeneous product is obtained. On increasing the proportion of antimony, however, crystals of the latter separate in a nearly pure state, and rising to the surface of the cooled product form a layer of a much lighter colour than the subjacent portion.The latter has a composition corresponding with the formula Pb,Sb, and appears to be the eutectic alloy of the two metals; it has a sp. gr.- 10.48, melts at about 247O, and solidifies in ill-defined hexagonal plates. Although all lead-antimony alloys, except the eutectic, have two critical points, one of these always corresponds with the fusing temperature of the compound Pb,Sb. MThen alloys of tin and antimony are melted and cooled, as long as the amount of the latter does not exceed 7.5 per cent., perfectly homogeneous products are obtained. On increasing the amount ofINORGANIC CHEMISTRY. 33 antimony, well-defined crystals separate, which consist of a combination of cubic and octahedral forms.They were isolated from the matrix by dissolving the latter completely in dilute nitric acid (sp. gr. = 1-04) ; thus obtained, they appear to consist of tin antimonide, SnSb, and have a sp. gr. = 6-96 (calc. 7.00). It appears that tin antimonide only crys- tallises from alloys containing an excess of tin; the crycJtaIs are formed best when 75 per cent. of the latter is present. On melting tin antimonide and allowing the mass to cool, cubic crystals are no longer formed in bhe solidifying mass; it appears that, like iron carbide, Fe,C, tin antimonide is decomposed by fusion. On melting alloys of tin and phosphorus containing from 0.04-5 per cent. of the latter, brilliant, white, crystalline plates of tin phos- phide, Sn3P,, separate on cooling; this was isolated by the same process as was used for preparing tin antimonide.It is decomposed when heated in a stream of hydrogen, phosphine being formed, whilst spontaneously inflammable hydrogen phosphide is evolved when any of the tin-phosphorus alloys are acted on by concentrated hydrochloric acid. A crystalline tin arsenic& mas isolated by the author from alloys of arsenic and tin ; it separates from the still molten tin at a temperature of 530°, and apparently has the composition Sn,As,. By H. F. HUNT and L. J. STEELE (J. Xoc. Chem. I t d . , 1896, 15, 849-850).- When aluminium is allowed to stand on mercury covered with a thick film of oxide, although apparently no amalgamation takes place, the aluminium is rapidly converted into its hydroxide. The action is not so rapid when the metal is kept beneath dirty mercury, and is very slight when aluminium is floated on freshly distilled mercury. The hydroxide is formed most rapidly on aluminium which has had its surface amalgamated by the ordinary methods.A Chloriodide of Tin. By C. LENOMAND (J. Pharm., 1898, [vi], 8, 249-253). -Although iodine does not act on anhydrous stannous chloride a t the ordinary temperature, it combines with it, when heated at 100' for several hours, forming tin chloriodide, SnC1,12. This is a mobile, red liquid, which fumes in the air, and has a sp. gr. = 3.287 at 15' ; i t is decomposed by water, and when poured into ether or ethylic, propylic, butylic, or smylic alcohol, gives rise to a crystalline compound. When tin chloriodide (100 grams) is heated, it begins to distil a t 19l0, but the temperature gradually rises to 297'; the residue (55.44 grams) in the flask at this temperature consists of nearly pure stannic iodide, EM,. I f the distillate obtained be redistilled, a further quantity of stannic iodide is left, and still more can be isolated by repeating the process. Ultimately, 67.78 per cent. of stnnnic iodide and 26.82 per cent. of stannic chloride were obtained ; the total result of the decomposition can therefore be expressed by the equation 2SnCl,I, = SnC1, + SnI,. Double Sulphfttes of Antimony and the Alkali Metals. By AUQUST GUTMANN ( A T c ~ . Pham., 1898, SEB, 477-479).-Antimony potassium dphate, KSb( SO,),, prepared by dissolving antimonious oxide W. A. D. Oxidation of Aluminium in Contact with Mercury. W. A. D. W. A. D. VOL. LXXVI. ii 339 ABSTRACTS OF CHEMICAL PAPERS. in a boiling solution of potassium sulphate in concentrated hydro- chloric acid, crystallises in small, six-sided, nacreous leaflets. The corresponding sodium salt forms small, scaly crystals, and the ammonium salt large, glistening leaflets. Action of Heat on the DoubleRhodium-AJkali Nitrites. By ALEXANDRE JOLY and EMILE LEIDI~ (Compt. vend., 1898,27,103-106). -The double nitrites of rhodium with potassium, sodium, and barium begin to decompose at about 360°, but the products a t this temperature are complex and indefinite. If, however, the salts are heated in a vacuum between 440' and incipient redness until evolution of gas ceases, and the products are then treated with water, definite, insoluble, crystalline compounds are obtained. The potassium salt yields the compound K20,6Rh0,, the sodium salt the compound Na,0,8Rh02, and the barium salt the compound BaO,l2RhO,. These compounds are t o be regarded as the salts of hexarhodous acid, octa- rhodous acid and dodecarhodous acid respectively, and the acids are products of the condensation of rhodous acid, H,O,RhO,. The existence of these compounds affords definite evidence of the existence of an oxide, Rho?, with an acidic function; they are analogous to the chromites, cobaltites and manganites obtained by G. Rousseau, and their formation seems to show that the production of salts of peroxides by the action of heat on double nitrites is a property common to many of the metals of the platinum group, A. W. C. C. H, B.