118 ABSTRACTS OF CHEMICAL PAPERS. I n o r g a n i c Chemistry. Chlorine Monoxide. By K. GARZAROLLI-THVRNLACKH and G. SCHACHERL (AnnaZen, 230, 2 73-286) .-Chlorine monoxide, prepared by the action of dry chlorine gas on well-dried precipitated mercuric oxide, is a dark bi-own liquid boiling at 5" under a pressure of 738 mm. The vapour has a yellowish-brown colour ; its density at 10" is 43-35, It is not decomposed by exposure to light. It dissolves in water,INORGANlC CHEMISTRY. 119 forming a yellow solution. When chlorine monoxide is passed over lime, chlorine is evolved and calcium hypochlorite formed. The oxide decomposes with explosive violence when it is brought in contact with organic matter. w. c. w. Bromine Absorption. By E. J. MILLS and J. MUTER ( J . 800. Chern.Ind., 4, 96-$%).--In the present paper, the authors hare tabulated a series of constants of bromine absorption f o r most of the important resins, a few elementary substances, and some interesting substances of a different nature. The absorplion was effected either in carbon bisulphide o r in carbon tetrachloride, and was determined by titration with P-naphthol or sodium thiosulphate and decinormal iodine, or by simple colorimetric comparison. Benzoic, cinnamic, and salicylic acids, camphor, naphthalene, and benzaldehyde gave no absorption in carbon tetrachloride. At ll", anthracene absorbs in tetrachloride 88.67 per cent. of bromine, corresponding with the ratio Cl4Hl0 : Br, ; at about 17" the absorption corresponds with CI4Hl0 : Br4. Of resinous substances, the absorption of shellac is below all other substahces of its class.As a rule, but not invariably, the greater the solubility of a gum resin the greater is its bromine absorption. The results with elementary substances are remarkable. Thus, tin-dust gives no absorption of bromine, arsenic absorbs in 12 hours 2.85 per cent., and aluminium in 1 hour 8-97 per cent. of bromine, carbon tetrachloride being used as the solvent. Zinc-dust takes u p bromine in the proportion Zn : Br2, and antimony in the pro- portion Sb : Brg. It has already been shown that aniline dissolved in carbon bisulphide absorbs bromine in the proportion 1 : 2. The authors consider it probable in this case, as in that of the toluidines, that additive and not substitution compounds are formed.The chemical activity of paratoluidine in carbon bisulphide, is less than in the case of tetrachloride, but, owing to the formation of yellow bye-products, carbon bisulphide is a better solvent for analyticnl purposes. carbon bisulphide being the solvent. In conclusion, it is shown that if the bromine absorption of mixtures of aniline with parat-oluidine is known, the composition of the mixture admits. of ready calculation. Solubility of Hydrogen Bromide at Different Temperatures and Pressures. By H. W. €3. ROOZEBOOM (Ren. Trav. Chinz., 4, 102-107) .-Determinations of the solubility of hydrogen bromide under pressures varying from 0 to 760 mm. were made at six temperatares between - 25" and 0". The results obtained formed similar curves for each temperature, the curves seem to be parabolic.The weight of gas dissolved by one part of water varies between 2.52 parts at - 25", and 2.2 parts a t 0", both under 760 mm: pressure, to 1.1 parts a t any temperature between - 25" and 0" when under 0.2 mm. pressure, A. P. 2C,H,N : Brz, Orthotoluidine takes up bromine in the proportion C7HgN : Br,, D. B.120 ABSTRACTS OF CHEMICAL PAPERS. Action of Nascent Hydrogen in Increasing the Activity of Oxygen. By F. HOPPE-SEYLER (Zeit. physioZ. Chein., 10, 36-39).- Tlie author criticises the views put forward on this subject by W. Pfeffer (Unters. not. Inst. Tubingen, 1, 636), arid by M. Traube (Rer., 16, 117, 1197), and affirms the accuracy of his own theory (Abstr., 1880, 3 ) . Reaction between Carbonic Oxide and Steam. By A. N A u M m N and c.PISTOR (Bey., 18, 2894-%397).-1n this paper, experiments are described made with a view of ascertaining the tern- perature at which carbonic oxide and steam react to form carbonic anhydride and hydrogen. The niet,hod consisted in passing carbonic oxide, freed from carbonic anhydride and oxygen, over water heated a t SO", so as to obtain an approximately equiiiiolecular proportion of carbonic oxide and vapour of water. The mixed gases were passed through a porcelain tube the temperature of which was roughly determined by introducing into it certain salts or spirals of various metals ; the resultant gas was then analysed by the usual methods. The following results were obtained :-At 560" no reaction took place, a t 600" 2 per cent., a t 900' 8 per cent., and a t 904" 10.5 per cent.of the carbonic oxide was converted into carbonic anhydride. All the conditions which militate against a reaction between carbonic anhydride and hydrogen are favourable to that between steam and carbonic oxide, inasmuch as such a change would be exothermic (+ 10730 cal.), and the resultant carbonic anhydride is very stable a t high temperatures, whilst the steam is readily decomposed into hydrogen and oxygen, the latter of which can burn the carbonic oxide. ATote by Abstractor.-The author seems to be unaware of, o r a t least docs not mention, the elaborate experiments of Dixon on the chemical interaction alluded to above (Abstr., 1885,479, and Trans., 1886,941). V. H. V. Crystalline Form of Calcium Hydroxide. By S. GLINKA (J. Auss.Chern. Soc., 1885, 451-452).-Crystals of the hydroxide, which had separated on the surface of samples of bydraulic cement, were found to belong to the rhombic system, notwithstanding their hexagonal appearance. Gay-Lussac obtained calcium hydroxide in the form of hexagonal plates by evaporating lime-water in a vacuum. A. T. Schloesing's Law Concerning the Solubility of Calcium Carbonate in Water containing Carbonic Anhydride. BJ- R. ENGEL (Compt. rend., 101, 949-951 ).-The author has already shown (Abstr., 1885, 484) that, the solubility of magnesium carbonate in water saturated with carbonic anhpdride, follows Schloesing's law up to a pressure of 6 atmos. Cnro's experiments (Arch. Pharnz. [3], 4, 145) indicate, however, that the law does not hold for calcium carbonate at pressures higher than that of the atmosphere. The author has therefore investigated the solubility of calcium carbonate at high pressures, the method of experiment being the same as ifi the case of the magnesium compound.The results obtained show thatINORGANIC CHEMISTRY. 12 1 Caro's experiments were inexact, and that the solubility of calcium carbonate follows Schloesing's law up to a pressure of 6 atmos., beyond which the experiments were not carried. The value actually found is, however, always slightly less than that calculated by means of Schloesing's formula, and the difference becomes greater the higher the pressure. The author's formula for the solubility of magnesium TKalso holds good for the calcium compound. 1 carbonate, y = - 16 Barium carbonate likewise obeys Schloesing's law a t high pressures, the results obtained being of the same order as in the case of calcium carbcnate.C. H. B. Normal Magnesium Carbonate. By R. ENGEL (Compf. rend., 101, 814-816).-When magnesium potassium hydrogen carbonate, MgCO,,KHCOJ + 4H20, is strongly heated, it melts arid yields a normal magnesium potassium carbonate, but if the triple carbonate is gradually and carefully heated up to 15U" or even W O O , i t does not melt but loses its water of crystallisation and half the carbonic anhydride previously combined with the potassiuni, and leaves a residue of transparent crystals which retain their original forin. These crystals are not a double magnesium &potassium carbonate, for if they are treated with water potassium carbonate is dissolved and magnesium carbonate is left in crystals which retain the form of t h o original crystals.If the normal magnesium carbonate thus obtained is left in contact w t l i water, it rapidly combines with it with development of heat, forming the pentahydrate if the temperature is below 16", and the trihydrate if it is above 16". The anhydrous carbonate even absorbs moisture from the air. It is much more soluble in water than the 113 drated carbonates, and its solution gradually deposits c q stals of the hydrated salt. properties from the natural carbonatc, and also from the aitificial crystals obtained hy Senarmont. If the mixture of potassium carbonate and magnesium carbonate is heated in an atmosphere saturated with aqueous vapour, water is absorbed and the carbonates combine without fusing to form a hydrated double carbonate which has the same crystalline form as the original compound, but is not transparent and seems to be black.This compourid is decomposed by water, but does not yield anhjdrous magiicsiurri ciirbonate, the 11 jdrated carbonate being foriiiecl in I ropor- tion as the decompositioii takes place. The same result is observed w lien the magnesium potassium hydrogen carbonate is decomposed by water. C. H. B. r 1 l h i s form of magnesium carbonate is obviously very different in its Combination of Normal Magnesium Carbonate with Potassium Hydrogen Carbonate. By R. ENGEL (Corn& rend., 101, 749--751).-The author has investigated the conditions under which normal magnesium carbonate combines with potassium hydrogen carbonate, and finds that for the same solution of potassium hydrogen carbonate the velocity of the reaction decreases as the122 ABSTlZXCTS OF CHEMICAL PAPERS.temperature rises. I f the temperature remains constant, the velocity increases with the initial concentration of the potassium solution. Combination ceases when it att,ains a certain limit, which is measured by the concentration of the solution of the potassium salt remaining in contact with excess of magnesium carbonate without combining with it. This limit increases with the temperature, and its variation is given by the formula y = m + nt + pt2, where y is the number of cubic centimetres of standard sulphuric acid required to neutralise the carbonates remaining in solution, and m, n, and f are constants having the values 2.5236, 0.0051 7, and 0.0031086 respectively.The product of the combination, MgC03,KHC0, + 4H20, is decomposed by water, and the decomposition tends towards a limit which is not identical with the limit of combination, but is always inferior to i t by a quantity which is practically the same for a'll temperatures. C. H. B. Double Nitrates of Silver and the Alkalis. By A. DITTE (Compt. rend., lO1,878--882).-When a solution containing silver and potassium nitrates is slowly concentrated, potassium nitrate at first crystallises alone, but as soon as the liquid contains a t least 3 mols. of silver nitrate for each mol.. of potassium nitrate bulky, transparent, right rhombic prisms are formed. These prisms are highly modified and have the composition AgNOa,KN03.This double salt is always foiamed when a solution of the two nitrates contains so much of the silver salt that both nitrrates can crystallise simultaneously. If the double salt is treated with water, the silver nitrate is gradually removed. Rubidium nitrate yields a strictly analogous double salt, and in all probability cmium nitrate will behave in the same way. If a solution of silver and ammonium nitrates is gradually concen- trated, the silver salt, being less soluble, cr.ystallises alone, but after a time the double nitrate AgNO3,NH,NO3, separates in crystals similar to t,hose of the potassium compound. This double s a l t is eaqily obtained whenever the mixed solutions contain an excess of the ammonium salt.Rose stated that a solution of silver and sodium nitrates contailling an excess of the former, first yields crystals of silver nitrate only, and afterwards crystals of the double nitrates AgN03,2NaN0, ; and AgNO3.4NaNO3. The author finds that when the silver nitrate is in excess, this salt crystallises alone in its ordinary form, but as soon as sodium nitrate begiris to separate also, the two salts crystdlise together, and the crystals take the ordinary form of sodium nitrate. Whatever the original composition of the solution, the composition of the crystals and the mother-liquor varies continuously, however, and no definite compounds are formed. From this result it follows that silver nitrate is dimorphous, and that one of its forms is iso- morphous with sodium nitrate, but the author has not been able to obtain pure silver nitrate in rhombohedrons. Lithium nitrate crystallises below 10" in prismatic needles con- taining 5H20, and if a mixture of silver and lithium nitrates is allowed to crystallise a t this temperature, the two salts crystalliseISORGANIC CHEMISTRY.123 separately. Above 15", however, lithium nitrate forms anhydrous crystals similar to those of sodium nitrate, and if a solution of silver and lithium nitrates is concentrated a t this temperature, the two salts crystallise together in rhombohedrons, but the composition of the crystals and the mother-liquor varies continuously as in the case of sodium nitrate, C. H. R. Anhydrous Cerium Chloride, and Cerium Silicate. By P. DIDIER ( C o n y f .rend., 101,882-884) .--Anhydrous cerium chloride is readily obtained by passing a carefully dried mixture of chlorine and carbonic oxide over cerosoceric oxide contained in a carbon dish. It is somewhat easily fusible, but only slightly volatile, highly deli- quescent, and dissolves completely in waber with considerable develop- ment of heat. Oxygen decomposes it at, a dull red heat with liberation of chlorine and formation of cerosoceric oxide. If bhe cerous chloride is previously mixed with sodium cliloride, the cerosoceric oxide forms crpfals which seem to belong to the cubic system, and have a metallic lustre and a brilliant red colour if they have been produced a t a high temperature. This variety of cerosoceric oxide seems to be identical with the crystals obtained by Grandeau by a different method (Abstr., 1885, 8i2).Cerous chloride is also decomposed by steam at a high temperature with formation of cerosoceric oxide and hydrochloric acid ; b u t if a mixture of steam and nitrogen is passed over a fused mixture of cerous and sodium chlorides, the oxychloride Ce302C12 is obtained in iridescent, micaceous scales with a silvery lustre. This compound is formed whenever hydrochloric acid and cerium oxide, or cerous chloride and water, are brought in contact at a high temperature, bnt if oxygen is also present, cerosoceric oxide is also formed. Cerous oxychloride is easily soluble in dilnte acids, and when heated in the air gives off hydrochloric acid, a residue of cerosoceric oxide being left. When silica and cerous chloride are heated together in a platinum dish in a non-oxidising atmosphere, the greater part of the silicon is volatilised in the form of tetrachloride, and long, colourless needles insoluble in water are left mixed with the excess of cerous chloride.These crystals have the composition Si02,2Ce0,2CeC12 ; they act on polarised light, undergo very little change in contact with water, but oxidise and become brown when exposed to the air. If cerium oxychloride is fused with silica and either sodium or calcium chloride, cerium silicate is obtained in highly modified prisms of sp. gr. 4.9, which act strongly on polarised light, and are more or less rapidly attacked by hydrochloric, nitric, and sulphuric acids, according to the concentration of the acid. This silicate has the composition SiO,,BCeO, and is therefore analogous to peridote.Lead Tetrachloride. By T. NIKOLUKINE ( J . Russ. Chem. XOC., 1885, 207-210).-The author finds that by the action of hydro- chloric acid on lead peroxide, the reaction being conducted a t a low temperature, lead tetrachloride is formed together with the dichloride. Potassium chloride forms with the tetrachloride a double salt, similar C. H. B.124 ABSTRACTS OF CHEMICAL PAPERS. to that with stannic chloride, soluble in a saturated solution of potassium chloride, lead dichloride being very sparingly soluble therein. With ammonium chloride, the reverse is the case, its double salt with lead tetrachloride being insoluble, and lead dichloride soluble in the saturated solution. Lead tetrachloride is a strong oxidking agent, acting even on platinum ; its solutions evolve chlorine after a time, and deposit crystals of the dichloride; when heated, chlorine is rapidly evolved.With caustic alkalis and their carbonates, a dark brown precipitate of lead peroxide is formed. I n the action of hydrochloric acid on lead peroxide, a double com- pound of the acid with the tetrachloride is most probably formed. Lead tetrachloride is decomposed by small quantities of water with evolution of chlorine ; with large quantities of water a red-brown coloration of the liquid occurs, apparently due to tlie formation of lead peroxide. A. T. Double Salts of Ferric Chloride with other Metallic Chlorides. By G. NEUMANN (Ber., 18, 2890--2894).-When a large quantity of ferric chloride is dissolved in hot fuming hydrochloric acid, and to it is added the metallic chloride whose double salt is required, and the liquid filtered, double salts of the general formula Pe2C1,,4RC1 + 2H,O separate out, on cooling.These crjstallise in the regular system, generally as microscopic octohedra or rhombic dodecahedra. In this paper, such double salts of ferric chloride with potassium, ammonium, rubidium, magnesium, and beryllium chlorides are described. Mdybdenum Residues. By W. VENATOR (Arch. Plmrm. [3], 23, 713-i14).-1f the residues contain no iron, sufficient ferric chloride is added to give a brownish-yellow colour to the solution. To separate the phosphoric acid, ammonia is added, the precipitate filtered off, and the filtrate is treated with barium chloride, whereby barium rnolybdate and sulphate are precipitated. The precipitate is well washed with hot water, and boiled for a long time with an equiva- lent amount of ammonium sulphate and water, with active agitation. The barium sulphate is filtered off, and the ammonium molybdate crystallised out..Crystallised Tin. By H. v. FOULLON (Juhrb. f. Min., 1885, 2, Ref., 266-268) .-From a series of measurements, the author concludes that only the following allotropic modifications may be regarded as diiferent :-Grey tin (sp. gr. 5.781 to 5.809) ; rhombic tin (sp. gr. 6.S.L to 6-56> ; and tetragonal tin (sp. gr. 7.196). The author is doubtful whether tlie moditication described as previously melted tin (sp. gr. 7.2795) differs from the tetragonal modification, as the differences in the sp.gr. of the two are not greater than the differences in the values obtained by different observers with tetragonal tin. These differences are obviously due to the numerous gas inclusions. V. H. V. The product thus obtained is very pure. J. T. B. H. B. Platinum Silicide. By C. G. NEMMINGER (Amer. Chern. J., 17%- 175).-Topax was inteusely ignited in a platinum crucible placed in a graphite crucible; at the end of the operation the platinum wasMISERALOGICAL CHEMISTRY. 125 found to be fused, having been converted into a brittle, fusible sub- stance containing 1.61 per cent. of silicon. H. B. Colour Reaction of Rhodium. By E. DEMARCAY (Corn@. rend., 101, 951-952).-A neutral or feebly acid solution of ammonium rhodiochloride, if sufficiently concentrated, gives a yellowish precipi- tate with a slight excess of sodium hypochlorite.If a 20 per cent. solution of acetic acid is added drop by drop to the liquid, with con- tinual agitat,ion, the precipitate dissolves and forms a somewhat intense orange-coloured solution, which rapidly decolorises, deposits a greyish precipitate, and finally acquires an intense sky-blue colour. This colour persists for severat hours, and then gradually disappears, but can be reproduced by repeating the same operations with the colourless liquid. The disappearance of the blue coloration is accele- rated by the presence of any free nitric or sulphuric acid, or of a large excess of acetic acid, and by a rise of temperature. The sodium hypochlorite solution should be freshly prepared and somewhat con- centrated ; an excess- exerts no injurious effect.It is immaterial whether the rhodium solution be originally yellow or red. Chlorides of other metals of the platinum group give no reaction with sodium hypochlorite under the same conditions. Small quanti- ties of rhodium can be detected in a mixture if two equal portions of the solution are taken for comparison, and one is diluted with water up to the same bulk as that with which the test is performed. I n this way, 0*0001 gram of rhodium can be detected in 3 C.C. of liquid, but the blue colour is very faint, and appears slowly. Wihh potash, the blue solutions of rhodium give a greenish precipi- tate which dissolves in acetic acid, with production of a dark-blue solution.C. H. B.118 ABSTRACTS OF CHEMICAL PAPERS.I n o r g a n i c Chemistry.Chlorine Monoxide. By K. GARZAROLLI-THVRNLACKH and G.SCHACHERL (AnnaZen, 230, 2 73-286) .-Chlorine monoxide, preparedby the action of dry chlorine gas on well-dried precipitated mercuricoxide, is a dark bi-own liquid boiling at 5" under a pressure of 738 mm.The vapour has a yellowish-brown colour ; its density at 10" is 43-35,It is not decomposed by exposure to light. It dissolves in waterINORGANlC CHEMISTRY. 119forming a yellow solution. When chlorine monoxide is passed overlime, chlorine is evolved and calcium hypochlorite formed. The oxidedecomposes with explosive violence when it is brought in contactwith organic matter. w. c. w.Bromine Absorption. By E. J. MILLS and J.MUTER ( J . 800.Chern. Ind., 4, 96-$%).--In the present paper, the authors haretabulated a series of constants of bromine absorption f o r most of theimportant resins, a few elementary substances, and some interestingsubstances of a different nature. The absorplion was effected eitherin carbon bisulphide o r in carbon tetrachloride, and was determinedby titration with P-naphthol or sodium thiosulphate and decinormaliodine, or by simple colorimetric comparison. Benzoic, cinnamic,and salicylic acids, camphor, naphthalene, and benzaldehyde gave noabsorption in carbon tetrachloride. At ll", anthracene absorbs intetrachloride 88.67 per cent. of bromine, corresponding with the ratioCl4Hl0 : Br, ; at about 17" the absorption corresponds with CI4Hl0 : Br4.Of resinous substances, the absorption of shellac is below all othersubstahces of its class. As a rule, but not invariably, the greater thesolubility of a gum resin the greater is its bromine absorption.Theresults with elementary substances are remarkable. Thus, tin-dustgives no absorption of bromine, arsenic absorbs in 12 hours2.85 per cent., and aluminium in 1 hour 8-97 per cent. of bromine,carbon tetrachloride being used as the solvent. Zinc-dust takesu p bromine in the proportion Zn : Br2, and antimony in the pro-portion Sb : Brg. It has already been shown that aniline dissolvedin carbon bisulphide absorbs bromine in the proportion 1 : 2.The authors consider it probable in this case, as in that of thetoluidines, that additive and not substitution compounds are formed.The chemical activity of paratoluidine in carbon bisulphide,is less than in the case of tetrachloride, but, owing to the formation ofyellow bye-products, carbon bisulphide is a better solvent for analyticnlpurposes.carbon bisulphide being the solvent.In conclusion, it is shown thatif the bromine absorption of mixtures of aniline with parat-oluidineis known, the composition of the mixture admits. of ready calculation.Solubility of Hydrogen Bromide at Different Temperaturesand Pressures. By H. W. €3. ROOZEBOOM (Ren. Trav. Chinz., 4,102-107) .-Determinations of the solubility of hydrogen bromideunder pressures varying from 0 to 760 mm. were made at sixtemperatares between - 25" and 0". The results obtained formedsimilar curves for each temperature, the curves seem to be parabolic.The weight of gas dissolved by one part of water varies between 2.52parts at - 25", and 2.2 parts a t 0", both under 760 mm: pressure, to1.1 parts a t any temperature between - 25" and 0" when under0.2 mm.pressure, A. P.2C,H,N : Brz,Orthotoluidine takes up bromine in the proportionC7HgN : Br,,D. B120 ABSTRACTS OF CHEMICAL PAPERS.Action of Nascent Hydrogen in Increasing the Activity ofOxygen. By F. HOPPE-SEYLER (Zeit. physioZ. Chein., 10, 36-39).-Tlie author criticises the views put forward on this subject by W.Pfeffer (Unters. not. Inst. Tubingen, 1, 636), arid by M. Traube (Rer., 16,117, 1197), and affirms the accuracy of his own theory (Abstr.,1880, 3 ) .Reaction between Carbonic Oxide and Steam. By A.N A u M m N and c.PISTOR (Bey., 18, 2894-%397).-1n this paper,experiments are described made with a view of ascertaining the tern-perature at which carbonic oxide and steam react to form carbonicanhydride and hydrogen. The niet,hod consisted in passing carbonicoxide, freed from carbonic anhydride and oxygen, over water heated a tSO", so as to obtain an approximately equiiiiolecular proportion ofcarbonic oxide and vapour of water. The mixed gases were passedthrough a porcelain tube the temperature of which was roughlydetermined by introducing into it certain salts or spirals of variousmetals ; the resultant gas was then analysed by the usual methods.The following results were obtained :-At 560" no reaction took place,a t 600" 2 per cent., a t 900' 8 per cent., and a t 904" 10.5 per cent.ofthe carbonic oxide was converted into carbonic anhydride.All the conditions which militate against a reaction between carbonicanhydride and hydrogen are favourable to that between steam andcarbonic oxide, inasmuch as such a change would be exothermic(+ 10730 cal.), and the resultant carbonic anhydride is very stablea t high temperatures, whilst the steam is readily decomposed intohydrogen and oxygen, the latter of which can burn the carbonic oxide.ATote by Abstractor.-The author seems to be unaware of, o r a t leastdocs not mention, the elaborate experiments of Dixon on the chemicalinteraction alluded to above (Abstr., 1885,479, and Trans., 1886,941).V.H. V.Crystalline Form of Calcium Hydroxide. By S. GLINKA(J. Auss. Chern. Soc., 1885, 451-452).-Crystals of the hydroxide,which had separated on the surface of samples of bydraulic cement,were found to belong to the rhombic system, notwithstanding theirhexagonal appearance. Gay-Lussac obtained calcium hydroxide in theform of hexagonal plates by evaporating lime-water in a vacuum.A. T.Schloesing's Law Concerning the Solubility of CalciumCarbonate in Water containing Carbonic Anhydride. BJ-R. ENGEL (Compt. rend., 101, 949-951 ).-The author has alreadyshown (Abstr., 1885, 484) that, the solubility of magnesium carbonatein water saturated with carbonic anhpdride, follows Schloesing's lawup to a pressure of 6 atmos. Cnro's experiments (Arch.Pharnz. [3],4, 145) indicate, however, that the law does not hold for calciumcarbonate at pressures higher than that of the atmosphere. Theauthor has therefore investigated the solubility of calcium carbonateat high pressures, the method of experiment being the same as ifithe case of the magnesium compound. The results obtained show thaINORGANIC CHEMISTRY. 12 1Caro's experiments were inexact, and that the solubility of calciumcarbonate follows Schloesing's law up to a pressure of 6 atmos.,beyond which the experiments were not carried. The value actuallyfound is, however, always slightly less than that calculated by meansof Schloesing's formula, and the difference becomes greater the higherthe pressure. The author's formula for the solubility of magnesiumTKalso holds good for the calcium compound.1 carbonate, y = -16Barium carbonate likewise obeys Schloesing's law a t high pressures,the results obtained being of the same order as in the case of calciumcarbcnate.C. H. B.Normal Magnesium Carbonate. By R. ENGEL (Compf. rend.,101, 814-816).-When magnesium potassium hydrogen carbonate,MgCO,,KHCOJ + 4H20, is strongly heated, it melts arid yields anormal magnesium potassium carbonate, but if the triple carbonate isgradually and carefully heated up to 15U" or even W O O , i t does notmelt but loses its water of crystallisation and half the carbonicanhydride previously combined with the potassiuni, and leaves aresidue of transparent crystals which retain their original forin.These crystals are not a double magnesium &potassium carbonate, forif they are treated with water potassium carbonate is dissolved andmagnesium carbonate is left in crystals which retain the form of t h ooriginal crystals.If the normal magnesium carbonate thus obtained is left in contactw t l i water, it rapidly combines with it with development of heat,forming the pentahydrate if the temperature is below 16", and thetrihydrate if it is above 16".The anhydrous carbonate even absorbsmoisture from the air. It is much more soluble in water than the113 drated carbonates, and its solution gradually deposits c q stals of thehydrated salt.properties from the natural carbonatc, and also from the aitificialcrystals obtained hy Senarmont.If the mixture of potassium carbonate and magnesium carbonate isheated in an atmosphere saturated with aqueous vapour, water isabsorbed and the carbonates combine without fusing to form ahydrated double carbonate which has the same crystalline form as theoriginal compound, but is not transparent and seems to be black.This compourid is decomposed by water, but does not yield anhjdrousmagiicsiurri ciirbonate, the 11 jdrated carbonate being foriiiecl in I ropor-tion as the decompositioii takes place.The same result is observedw lien the magnesium potassium hydrogen carbonate is decomposed bywater. C. H. B.r 1 l h i s form of magnesium carbonate is obviously very different in itsCombination of Normal Magnesium Carbonate withPotassium Hydrogen Carbonate. By R.ENGEL (Corn& rend.,101, 749--751).-The author has investigated the conditions underwhich normal magnesium carbonate combines with potassiumhydrogen carbonate, and finds that for the same solution of potassiumhydrogen carbonate the velocity of the reaction decreases as th122 ABSTlZXCTS OF CHEMICAL PAPERS.temperature rises. I f the temperature remains constant, the velocityincreases with the initial concentration of the potassium solution.Combination ceases when it att,ains a certain limit, which is measuredby the concentration of the solution of the potassium salt remainingin contact with excess of magnesium carbonate without combiningwith it. This limit increases with the temperature, and its variationis given by the formula y = m + nt + pt2, where y is the number ofcubic centimetres of standard sulphuric acid required to neutralisethe carbonates remaining in solution, and m, n, and f are constantshaving the values 2.5236, 0.0051 7, and 0.0031086 respectively.The product of the combination, MgC03,KHC0, + 4H20, isdecomposed by water, and the decomposition tends towards a limitwhich is not identical with the limit of combination, but is alwaysinferior to i t by a quantity which is practically the same for a'lltemperatures.C. H. B.Double Nitrates of Silver and the Alkalis. By A. DITTE(Compt. rend., lO1,878--882).-When a solution containing silver andpotassium nitrates is slowly concentrated, potassium nitrate at firstcrystallises alone, but as soon as the liquid contains a t least 3 mols.ofsilver nitrate for each mol.. of potassium nitrate bulky, transparent,right rhombic prisms are formed. These prisms are highly modifiedand have the composition AgNOa,KN03. This double salt is alwaysfoiamed when a solution of the two nitrates contains so much of thesilver salt that both nitrrates can crystallise simultaneously. If thedouble salt is treated with water, the silver nitrate is graduallyremoved.Rubidium nitrate yields a strictly analogous double salt, and in allprobability cmium nitrate will behave in the same way.If a solution of silver and ammonium nitrates is gradually concen-trated, the silver salt, being less soluble, cr.ystallises alone, but after atime the double nitrate AgNO3,NH,NO3, separates in crystals similarto t,hose of the potassium compound.This double s a l t is eaqilyobtained whenever the mixed solutions contain an excess of theammonium salt.Rose stated that a solution of silver and sodium nitrates contaillingan excess of the former, first yields crystals of silver nitrate only,and afterwards crystals of the double nitrates AgN03,2NaN0, ; andAgNO3.4NaNO3. The author finds that when the silver nitrate is inexcess, this salt crystallises alone in its ordinary form, but as soon assodium nitrate begiris to separate also, the two salts crystdlisetogether, and the crystals take the ordinary form of sodium nitrate.Whatever the original composition of the solution, the compositionof the crystals and the mother-liquor varies continuously, however,and no definite compounds are formed.From this result it followsthat silver nitrate is dimorphous, and that one of its forms is iso-morphous with sodium nitrate, but the author has not been able toobtain pure silver nitrate in rhombohedrons.Lithium nitrate crystallises below 10" in prismatic needles con-taining 5H20, and if a mixture of silver and lithium nitrates isallowed to crystallise a t this temperature, the two salts crystallisISORGANIC CHEMISTRY. 123separately. Above 15", however, lithium nitrate forms anhydrouscrystals similar to those of sodium nitrate, and if a solution of silverand lithium nitrates is concentrated a t this temperature, the two saltscrystallise together in rhombohedrons, but the composition of thecrystals and the mother-liquor varies continuously as in the case ofsodium nitrate, C.H. R.Anhydrous Cerium Chloride, and Cerium Silicate. ByP. DIDIER ( C o n y f . rend., 101,882-884) .--Anhydrous cerium chlorideis readily obtained by passing a carefully dried mixture of chlorineand carbonic oxide over cerosoceric oxide contained in a carbon dish.It is somewhat easily fusible, but only slightly volatile, highly deli-quescent, and dissolves completely in waber with considerable develop-ment of heat. Oxygen decomposes it at, a dull red heat with liberationof chlorine and formation of cerosoceric oxide. If bhe cerous chlorideis previously mixed with sodium cliloride, the cerosoceric oxide formscrpfals which seem to belong to the cubic system, and have a metalliclustre and a brilliant red colour if they have been produced a t a hightemperature. This variety of cerosoceric oxide seems to be identicalwith the crystals obtained by Grandeau by a different method (Abstr.,1885, 8i2).Cerous chloride is also decomposed by steam at a high temperaturewith formation of cerosoceric oxide and hydrochloric acid ; b u t if amixture of steam and nitrogen is passed over a fused mixture ofcerous and sodium chlorides, the oxychloride Ce302C12 is obtained iniridescent, micaceous scales with a silvery lustre. This compound isformed whenever hydrochloric acid and cerium oxide, or cerouschloride and water, are brought in contact at a high temperature,bnt if oxygen is also present, cerosoceric oxide is also formed.Cerousoxychloride is easily soluble in dilnte acids, and when heated inthe air gives off hydrochloric acid, a residue of cerosoceric oxidebeing left.When silica and cerous chloride are heated together in a platinumdish in a non-oxidising atmosphere, the greater part of the silicon isvolatilised in the form of tetrachloride, and long, colourless needlesinsoluble in water are left mixed with the excess of cerous chloride.These crystals have the composition Si02,2Ce0,2CeC12 ; they act onpolarised light, undergo very little change in contact with water,but oxidise and become brown when exposed to the air. If ceriumoxychloride is fused with silica and either sodium or calcium chloride,cerium silicate is obtained in highly modified prisms of sp.gr. 4.9,which act strongly on polarised light, and are more or less rapidlyattacked by hydrochloric, nitric, and sulphuric acids, according to theconcentration of the acid. This silicate has the composition SiO,,BCeO,and is therefore analogous to peridote.Lead Tetrachloride. By T. NIKOLUKINE ( J . Russ. Chem. XOC.,1885, 207-210).-The author finds that by the action of hydro-chloric acid on lead peroxide, the reaction being conducted a t a lowtemperature, lead tetrachloride is formed together with the dichloride.Potassium chloride forms with the tetrachloride a double salt, similarC. H. B124 ABSTRACTS OF CHEMICAL PAPERS.to that with stannic chloride, soluble in a saturated solution ofpotassium chloride, lead dichloride being very sparingly solubletherein.With ammonium chloride, the reverse is the case, its doublesalt with lead tetrachloride being insoluble, and lead dichloridesoluble in the saturated solution. Lead tetrachloride is a strongoxidking agent, acting even on platinum ; its solutions evolvechlorine after a time, and deposit crystals of the dichloride; whenheated, chlorine is rapidly evolved. With caustic alkalis and theircarbonates, a dark brown precipitate of lead peroxide is formed.I n the action of hydrochloric acid on lead peroxide, a double com-pound of the acid with the tetrachloride is most probably formed.Lead tetrachloride is decomposed by small quantities of water withevolution of chlorine ; with large quantities of water a red-browncoloration of the liquid occurs, apparently due to tlie formation oflead peroxide.A. T.Double Salts of Ferric Chloride with other Metallic Chlorides.By G. NEUMANN (Ber., 18, 2890--2894).-When a large quantity offerric chloride is dissolved in hot fuming hydrochloric acid, and to it isadded the metallic chloride whose double salt is required, and theliquid filtered, double salts of the general formula Pe2C1,,4RC1 + 2H,Oseparate out, on cooling. These crjstallise in the regular system,generally as microscopic octohedra or rhombic dodecahedra. In thispaper, such double salts of ferric chloride with potassium, ammonium,rubidium, magnesium, and beryllium chlorides are described.Mdybdenum Residues. By W. VENATOR (Arch.Plmrm. [3],23, 713-i14).-1f the residues contain no iron, sufficient ferricchloride is added to give a brownish-yellow colour to the solution.To separate the phosphoric acid, ammonia is added, the precipitatefiltered off, and the filtrate is treated with barium chloride, wherebybarium rnolybdate and sulphate are precipitated. The precipitate iswell washed with hot water, and boiled for a long time with an equiva-lent amount of ammonium sulphate and water, with active agitation.The barium sulphate is filtered off, and the ammonium molybdatecrystallised out..Crystallised Tin. By H. v. FOULLON (Juhrb. f. Min., 1885, 2, Ref.,266-268) .-From a series of measurements, the author concludesthat only the following allotropic modifications may be regarded asdiiferent :-Grey tin (sp.gr. 5.781 to 5.809) ; rhombic tin (sp. gr. 6.S.Lto 6-56> ; and tetragonal tin (sp. gr. 7.196). The author is doubtfulwhether tlie moditication described as previously melted tin (sp. gr.7.2795) differs from the tetragonal modification, as the differences inthe sp. gr. of the two are not greater than the differences in thevalues obtained by different observers with tetragonal tin. Thesedifferences are obviously due to the numerous gas inclusions.V. H. V.The product thus obtained is very pure. J. T.B. H. B.Platinum Silicide. By C. G. NEMMINGER (Amer. Chern. J., 17%-175).-Topax was inteusely ignited in a platinum crucible placed ina graphite crucible; at the end of the operation the platinum waMISERALOGICAL CHEMISTRY. 125found to be fused, having been converted into a brittle, fusible sub-stance containing 1.61 per cent. of silicon. H. B.Colour Reaction of Rhodium. By E. DEMARCAY (Corn@. rend.,101, 951-952).-A neutral or feebly acid solution of ammoniumrhodiochloride, if sufficiently concentrated, gives a yellowish precipi-tate with a slight excess of sodium hypochlorite. If a 20 per cent.solution of acetic acid is added drop by drop to the liquid, with con-tinual agitat,ion, the precipitate dissolves and forms a somewhatintense orange-coloured solution, which rapidly decolorises, depositsa greyish precipitate, and finally acquires an intense sky-blue colour.This colour persists for severat hours, and then gradually disappears,but can be reproduced by repeating the same operations with thecolourless liquid. The disappearance of the blue coloration is accele-rated by the presence of any free nitric or sulphuric acid, or of a largeexcess of acetic acid, and by a rise of temperature. The sodiumhypochlorite solution should be freshly prepared and somewhat con-centrated ; an excess- exerts no injurious effect. It is immaterialwhether the rhodium solution be originally yellow or red.Chlorides of other metals of the platinum group give no reactionwith sodium hypochlorite under the same conditions. Small quanti-ties of rhodium can be detected in a mixture if two equal portions ofthe solution are taken for comparison, and one is diluted with waterup to the same bulk as that with which the test is performed. I n thisway, 0*0001 gram of rhodium can be detected in 3 C.C. of liquid, but theblue colour is very faint, and appears slowly.Wihh potash, the blue solutions of rhodium give a greenish precipi-tate which dissolves in acetic acid, with production of a dark-bluesolution. C. H. B