INORGANIC CHEMISTRY. PO3I n o r g a n i c Chemistry.Formation of Hydrogen Peroxide by the Explosion of aMixture of Oxygen and Hydrogen. By R. BOTTGER (Clmn. Centr.,1878, 574).-1f two volumes of hydrogen and m e volume of oxygen beexploded in a small flask, hydrogen peroxide may be readily detectedafi,er the explosion, by adding a little starch-paste containing cadmiumiodide i n solution, followed by the addition of a crystal of ammonium-ferrous snlphate.By exploding ether vapour mixed with air, ozone is produced, butno peroxide of hydrogen ; a similar experiment with anhydrous alcoholyielded no ozone. M. M. P. M.Reduction of Iodates by Phosphorus. By J. CORNE ( J . PJmrnz.Chi))?., [4], 28, 386--389).-Moist phosphorus in presence of air,reduces iodic acid and iodates at the ordinary temperature, but if airbe excluded no reduction takes place.This reduction cannot be due tophosphorous or hypcphosphorous acid, because in the case of the former,reduction only takes place at a temperature of 80-90°, and in thelatter a t about 50'.If phosphorus is immersed in water, and the air above the waterconfined, the phosphorus becomes oxidised, and the products of oxicla-tion are dissolved in the water. This solution will immediately reducepotassium iodate. The aul hor, therefore, supposes that besides phos-phorous and hypophosphorous acids being formed, a body more greedyfor oxygen than the latter, perhaps an acid containing less oxygen, isi 104 ABSTRACTS OF CHEMICAL PAPERS.formed, and that hypophosphorous acid, H3P02, is the second of aseries of acids, in which this unknown body stands first, with aformula, H,PO.Mercury often prevents this reduction.L. T. 0's.Solubility of Sulphur and Phosphorus. By G. VULPIUS (Arch.Pharm. [3], 13, 2%9-231).-At loo", 1 part of sulphur is soluble in2,800 parts of strong formic acid, but is separated from its solutionon cooling ; the separation is less remarked if the solution is dilutedwith water of the same temperature, but i t is very evident if the wateris cold. The contrary takes place in the case of a solution of phos-phorus in acetic acid, the precipitation being greater if the liquid bediluted than if i t be cooled. Phosphorus is soluble in formic acidonly in traces. Of all the fatty acids, btearic acid is the only onewhich dissolves any appreciable quantity of phosphorus or sulphur.An alcoholic solution of the stearic acid solution of phosphorus whencooled, assumes a gelatinous form.Researches on the Sulphates.By A. ETARD (Compt. rend.,87, 602-604) .-The new compound sesquisulphates previouslydescribed by the author are not the only combinations possible.Bodies of the general form, M2(S0,),.NSO4.nSO4H? ; compound snl-phates of the formula 2( S04MS04N) .nSO,H, ; and simple or doublemore or less hydrated sulphates may be obtained.Ferrosoferric SuZphate, Pe2(SO4),.FeSO4.2H,SO4 is obtained in small,pink, hexagonal plates, by dissolving in as little water as possibleequivalent quantities of ferrous and ferric sulphates, adding a greatexcess of concentratcd sulphuric acid, and heating to about 200".Ina similar way have been also prepared, Cr2( S0,),.NiSO4.2SO4H2.3H2O,Crz( SO,),ZSO,Fe S06H2.2H20, Cr2( S0,),2S04CuS04Hz,Fe3( SO,),. S04Ni. 2 S04H2, Fez( S 0,) 3. 2 SO,Nn.3 S04H2,Al,( S04),.2S04Fe. S04Hz. Al,( S04),.2Ni S0,.S04H2.E. W. P.All these salts are insoluble in water, but are decomposed by itafter a time. The above formule, together with the author's otherobservations, show that a molecule of acid can replace a molecule ofprotosulphate in these compounds, and vice uersd, according to thenature of the metal and the temperature.The compound protosulphates are prepared by dissolving the corre-sponding salts in as little water as possible, and precipitating by alarge excess of concentrated eulphuric acid.Thus are obtained2(NiS0,ZnS04) S0,H2, 2( FeSO,ZnSO,) SOcH2, 2( CuSO,ZnSO,) S04H2,2 ( CuS0,Co S 0,) S04H2, 2 ( FeS04CoS04) SO4H2, 2 ( S04CuNiS 0,) SO,H,,and 2(NiSOaFeS0,)2S04H2. With the ferrous and cupric sul-phates, a brick-red crystallised salt is precipitated. This containsS0,CuS04Fe.2Hz0 ; it loses its water a t a higher temperature, turnsviolet, and then contains SO,Fe.SO&u, keeping its crystalline form.These salts are not oxidised by fuming nitric acid, even on boiling.S04Cu.S0,Mn.H20 and S04Cu.S0,Ni.3Hz0 are also obtained in micro-scopic crystals by the same method.By substituting the simple salts for the preceding mixtures, themono- and hi-hydrated salts are obtained in crystalline form :-S 0,Co.H20, SOpNi. 2 H,O, S 04ZnHz0, S04CuH20, S 04FeH20INORGANIC CREAMISTRY. 105The protosulphates dissolved in boiling concentrated sulphuric acidAll these bodies present to the nakedThe nickel and cobaltare deposited in crystalline form.eye a more or less shining sandy appearance.salts are gradually decomposed and dissolved by water.C. E. C.Action of Hydrochloric Acid Gas on Sulphates. By C.HENSGEN (Deut. Ciienz. Ges. Ber., 11, 1775-1 778).-Dry hydro-chloric acid has no action on anhydrous ferrous sulphate a t theordinary temperature, but a t a higher temperature ferric chloride,sulphur trioxide, and sulphur dioxide are formed. When hydrochloricacid is passed into a saturated solution of ferrous sulphate, ferrouschloride separates out,, and the mother-liquor deposits tabular crystalsof the salt FeSOa.6H20.w. c. w.Action of Hydrochloric Acid on Double Sulphates. By C.HEXSGEN (Deut. Chem. Ges. Ber., 11, 1778--1781).-When hydro-chloric acid is passed into a saturated solution of potassium-coppersulphate, green crystals separate ouh, having the compositionThe compounds K4Ye2ClG + 2H20 and (NH,),Fe2Cll0 + 2H20 wereobt'ained by the action of hydrochloric acid on concentrated solutionsK,CUCI,~H~O.of potassium and ammonium iron alums. w. c. w.Hypophosphoric Acid and its Salts. By T. SALZER (Liebig'sAiznalen, 194, 28--39).-Au abstract of the earlier part of this researchappeared in this Journal, 1877, 2, 702.Some further observations are first made on the formation of tlieabove acid.The oxidation of the phosphorus is much assisted, iflarge quantities are left to the action of the air and water in the samespace. This is effected, probably not by rise of temperature, but bythe stronger ozoriising of the air, or otherwise by the more active for-mation OE hydrogen peroxide, for the phosphorus is most corrodedwhere it dips into the liquid. It is also remarked that the formationof the hypophosphoric acid proceeds with that of the phosphorousand phosphoric acids in a certain ratio, until the liquid becomes soconcentrated that no more of the first acid can be formed : only about&th part of the phosphorus is converted into hypophosphoric acid,phosphoric acid being the chief product. With regard to his formerstatement, the autlior now says that hypophosphoric acid decomposesboth sodium chloride and sodium sulphate.The formation of crystalsof the acid sodium salt only requires more time, if the solution is notvery concentrated. The salt can be directly prepared by leavingsticks of phosphorus partially immersed in dilute solution of sodiumchloride (e.g., 1 : loo), and allowing oxidation to take place.Neutral Hypopl~ospha t P ,Xa,(POJj2 + 10H20.-If to a solution of 1 part of the acid salt in 50parts of water, a concentrated solution of 1 part of soda is added, thesolution remains clear, but if soda solution be gradually added, beauti-ful prismatic, needle-shaped crystals separate, consisting of the neutralSod imz-cu?nyourds of Hypp I q d m - i c Acid106 ABSTRACTS O F CHEMICAL PAPERS.salt, and belonging to the monoclinic system.Observed facesOP, 2Pm, cop, P, +P.The neutral salt is rather less soluble in water than the acid salt,viz., in 50 times the quantity, The cold saturated solution turnsturmeric paper brown, and concentrated soda solution precipitatesfrom i t the unaltered neutral salt. + 9 K O . - 0 h-tained by acting with less than one part by weight of crystallisedsodium carbonate on one part of the acid sodium hypophosphate insolution. The solution of this salt has an alkaline reaction. It losesits water of crystallisation a t 100". At higher temperatures i t sud-denly takes fire, and burns with a steady flame (phosphorettedhydrogen gas being liberated). The crystals belong to the mono-clinic system, and are of a glassy lustre. They are mostly of tabularform, through a predominating OP.Acid Putassium Hypophosphate, K,H,(PO,), + H20.-Pure hypo-phosphoric acid neutralised with potassium carbonate and evaporatedto syrupy consistency, gave crystalline nodules, which have not yetbeen analysed.On adding an equal quantity of acid, crystals of theabove salt were obtained. I t is soluble in double its weight of watera t the ordinary temperature, but is not soluble in alcohol. On heating,it decomposes and gives off hydrogen which burns, whilst insolublepotassium metaphosphate is left behind. It crystallises in the rhonibicsystem. The crystals are small, transparent, and colourles?, and-a corn-bination of prism GOP with pyramid 2p2 ; subordinate ooP00, Pcr, andOP.A con-centrated solution of this salt was used successfully to detect 0*00:3soda, which had been dissolved in 1 C.C. of water, and existed aschloride or sulphate.Hypophosphoric acid produces a crystalline precipitate in a solutionof lithium carbonate, soluble in water with great difficulty, but easilysoluble in excess of hypophosphoric acid.Neutral A?n?)zo?zizcm Hypophosphute, (NH,),(PO,)? + H,O.- Obtainedby heating a 5 per cent. solution of the acid with excess of ammo-nia. The crystals begin to fall or effloresce immediately after drying,and so could not be measured. They appear to consist of prismaticcolumns, with pyramidal-faced ends, and are soluble in 30 times theirweight of water, the solution reacting strongly alkaline.By evapora-tion, ammonia is driven off, the solution soon acquires an acid reaction,and a t last furnishes the acid ammonium hypophosphate. Theneutral salt loses ammonia even on standing in the air, and the clearcrystals assume a turbid or milky appearance. On warming theymelt, with strong evolution of ammonia, and a t last with combustionof the liberated hydrogen. This latter property is peculiar only tothe acid hypophosphates.Acid Arnnzo?zium Hypophosphate (NH4)2H2(P03)z.-If the solutionof the previous salt be boiled until ammonia ceases to escape, the acidanimonium salt is formed, and may be obtained in needles ; i t is isomor-phous with the acid potassium salt.Neutral Bariimt Eypophosphate, Ba2(P03)2.-This salt is thrownclown from a solution of neutral sodium hypophosphate by bariumCleavage parallel to m P a .Trisodi?Lm- h y d yog en I€ypop h osplt at e, Na3H ( P 0,)The normal potassium salt could not be obtained pureINORGANIC CHEMISTRY.107chloride as an apparently amorphous precipitate. It is very slightlysoluble iu water, also in acetic acid, more soluble in hydrochloric andhypophosphoric acids. It is anhydrous, and when heated passes overinto reddish barium pyrophosphate without any appearance of combus-tion. Even by very rapid heating of the damp neutral barium salt,it is not possible to effect the oxidation of the hypophosphoric acid bymeans of the oxygen of the air.Acid Barium Hpophosphate, BaH?( PO3), + 2H20.-Prepnred fromthe acid sodium salt by precipitation with barium chloride.On mixinghot solutions of 4 parts of acid sodium salt in 180 parts of water, and of5 parts of barium chloride in 10 parts of water, and immediately filtering,beautiful crystals were obtained on cooling. They belong to themonoclinic system, and are needles formed of OP and mPm. Theyare clear, but become turbid on heating under water. They give asolution with 1,000 parts of cold water, which reacts acid, and becomesturbid on boiling in consequence of the separation of neutral or basicbarium hypophosphate. The crystals scarcely suffer any loss inweight by heating a t loo", but a t 140" slowly lose the 2 atoms ofwater of crystallisatio~i, and at, higher temperatures pass, with combus-tion of escaping hydrogen, into barium metaphosphate, which fuses toa white bead.Neutral Cdciurn Hypophosphate, C k ( PO,), + 2H20.--In neutralcalcium solutions, neutral sodium hypophosphate even of 200,000-folddilution, gives rise to a perceptible turbidity.With greater concen-tratiou the solution assumes alkalinity, and all the calcium is preci-pitated. On the contrary, on adding calcium chloride to the sodiumsalt, the alkaline reaction disappears with completed precipitation ofthe hypophosphoric acid.After washing, the original very gelatinous precipitate quicklybecomes denser, granular, and appears under the microscope as rounded,but non-crystalline particles, and by continued washing suffers anotherchange, whereby i t becomes so finely divided as to go through thedensest double or triple filters.It is insoluble in water and almostinsoluble in acetic acid, but easily soluble in hydrochloric and hypo-phosphoric acids.The crjstallisation-water is most difficult to determine, as i t begins topass off a t loo", although the salt must be brought to 200" before all canbe driven off, and then slight decomposition (i.e., oxidation) ensues.Acid C'ulci.zm Hypoplmphate could not be obtained in the solid form,as neither the dilute nor the concentrated hypophosphoric acid woulddissolve as much neutral calcium salt as is necessary for the for-mation of the acid salt. The author finally points out that as onlyone lime compound of this acid appears to exist, it will be possible totitrate neutral calcium solutions by means of neutral sodium hypo-phosphate, after addition of red litmus tincture.Alkaline reactionsets in after completed precipitation. The same remark applies tosalts of lead and other metals. w. s.Preparation of Salts in a Finely Divided State. By R. BOT.T-GER (Chewz. Centr., 1878, .560).-Salts which are insoluble, or onlyslightly soluble, in alcohol, may be obtained in a very finely divide108 ABSTRACTS OF CHEMICAL PAPERS.state by dissolving them in boiling wat,er and pouring the concentratedsolution drop by drop into alcohol. M. M. P. &l.Green and Blue Ultramarine. By G. H. PHILIPP (Liebiy’sAnnaleii, 191, l-l2).-This paper contains the results of the furtherapplication of the author’s method (Am., 184, 132) to the compara-tive investigation of these products.It is shown that all varieties ofblue ultramwine prepared in the wet way by the action of reagents,e.g., water (in sealed tubes), zinc sulphate, ammonium chloride, bopicacid, upon the green, resemble the latter in their decomposition by acids.In the dry way green is readily converted into blue ultramarine (1) byfusion withammonium chloride. The composition of the product is essen-tially thatof theordinary bluevariety. If the access of air be prevented asmilch as possible, its composition approximates somewhat to that of thegreen. In all cases water dissolves someNaClfronithe fusedmass. (2.) Byheating in chlorine gas. This product also closely resembles the ordinaryblue varieties.The chemistry of the conversion of green into blueultramarine consists essentially in the oxidation of its sulphur (toSO2 or S202) ; this is proved by the accompanying comparative analyses,and indirectly by the change in composition of the blue varietybrought about by heating it in a current of hydrogen, when it approxi-mates closely to that of the green, the colour remaining unchanged.The author also finds that on heating blue ultramarine (Marienberg)over the blowpipe, the air being as far as possible excluded, i t is con-verted into a green mass having the composition of the ordinary greenvariety. In conclusion, he states, as the principal result of his investi-gation, that the chemical difference between these two ultramarines isUltramarine.By R. HOFFMAXN (Liebig’s AniiaZen, 194, 1-22).-In the earliest researches on ultramarine, it was observed that,on decomposing it with acids, a part of the sulphur contained inthe colour was precipitated, whilst another part escaped as hydrogensul phide, and later, that green ultyamarine furnished relatively morehydrogen sulphide and less free sulphur, than blue ultramarine ; andit was believed also that in green ultramarine there was, besides thealumino-sodium silicate, a lower, and in blue ultramarine a highersulphide of sodium, or that blue ultramarine contained more sulphurthan the green. The oldest researches made with ultraniarine poor insilica, do not harmonise with this, for they showed that these per-centages were about equal, and afterwards when ultramarines rich insilica were prepared, the blue ultramarine richer in sulphur was lookedon as the higher step of sulphurisation of the green ultramarine, andit was assumed that the green variety in the refining-roasting processwith sulphur passed, with absorption of sulphur, into the blue.Although much has been done towards clearing up this intricatesubject, the time has not yet come for a well-founded theory of thecbemical constitution of the ultramarine compouitds, or of the causeof their different colours.The author therefore intended his essaymerely as a contribution towards a true theory of the ultramarine com-pounds, to be framed a t some future time.the sodium sulphide contained i n the green variety.c. P. cINOROXNIC CHEMISTRY. 109By fusing sulphur with sodium oxide or carbonate, or by reductionof the sulphate, the following reactions take place, disregarding inter-mediate compounds, which may be formed,Na,S + 4s = Na2P,5Na,S-4Na2 = Na2Sj.If it, be assumed that there are alumino-silicates of sodium in whicha part of the oxygen in closer connection with sodium is replaceable bysulphur, and that such silico-sulphides behave similarly to the freesodium monosulphide, i.e., by absorption of sulphur or by giving upsodium, higher sulphides can arise without the whole silico-sulpliidebeing decomposed, then these assumptions suffice to explain the for-mation of the ultramarines by the known methods of preparation, theirchemical behaviour generally, and their relations to one another.Thefollowing shows this for the ultramarines poor in silica.The composition of the pure air-dried kaolin is expressed by theformula (Rammelsberg) HzA1,Si,08 + Aq, or &AI,SiZO9. If an inti-mate mixture of kaolin and sodium carbonate be ignited just as theordinary ultramarine mixture is (30 parts dry clay.to 18 of sodiumcarbonate), a complete combination of the clay with soda takes place,and the composition of the combined mass may be represented asNa2A1,Si20,, or sodium alumino-silicate. Now it is cocsidered thatthis compound may be regarded as the silicate actually contained inthe ultramarine compounds poor in silica, and that by taking upsodium, sulphur compounds it is converted into ultramarine.I n fact,very good ultramarine is obtained on treating the fused mass withan excess of soda, sulphur, and resin, and submitting to the roastingprocess as with ultramarine. If clay a t a high temperature and withproper exclusion of air be ignited with an excess of sodium sulphateand charcoal, or with soda, sulphur, and charcoal, the clay satu-rates itself with soda, and then this compound becomes united withsodium sulphide, forming the while uZtra~nari?ie of Ritter. Tbewhite u7tra)mrisie is represented as NarA1,Si20,S or N%A12Si,08 -t-Na2S. Thus one-half of the water in the air-dried clay appears to bereplaced by NhO, and the other by Na2S. White ultramarine of thispurity must contain the whole sulphur as monosulphide, and by decom-posing it with a’cids yield it as hydrogen sulphide without depositionof sulpliur.Such a pure ultramarine has never been obtained ; but$hat prepared by the author gave for tzoo of sulphur as hydrogensulphide, m e as sulpliur itself. Ritter obtained the proportion 3 : 1.From the great difficulty of obtaining white ultramarine in the purestate, the analytical numbers only approximate to those required bythe formiila-White Ultramarine.Si?. 8 1 2 . Na4. S. 08.15.4 15.0 25.4 8.9 35.3 (calculated)18.3 16.6 19.0 6.1 39.7 (Ritter)17.0 16.6 21.5 6.5 38.4 (Hoffmann)If sodium be extracted from the yvhite ultramarine, the latter passes,with continual colour-change, through yellow and green, graduallyint.0 blue ultramarine without further process or addition.Themeans employed are, oxygen in presence of free sulphur, or chlorin110 ABSTRACTS OF CHEMICAL PAPERS.alone. The extracted sodium then goes out either as sulphate or aschloride. In this removal of sodium, the mode of combination of thesulphur changes in the same way as with the free sodium monosul-phide under corresponding conditions, somewhat after the manner ofthe formula, 3Nn2S - 2Naz = Na2S3 or 5Na2S - 4Naz = Na2S,. I t ap-pears very doubtful. if the green ultram'arine is a true chemical com-pound. Theoretically, it is an intermediate body between the whiteand the blue, and probably nearer the latter than the former. Withthe object of throwing light upon the constitution of the intermediateproduct, the blue ultramarine was investigated.The iodine methodgave the proportion Sn : Sb exactly as 1 : 3, or in reference to sodiumsulphide one must assume in blue ultramarine Na2S4. If it be con-ceded that the passage of white into blue ultramarine rests on removalof sodium, then the blue ultramarine is formed by removal of 3 mole-cules of sodium from 4 molecules of the white ultramarine.Na16A18Si80J2S, - Na6 = NaloAI,S8032S4.White ultramarine. Blue ultramarine.4(Xa,il12Si20, + Na,S) 4(Xa~AlLSi20a) +, Na2SJBlue Ultramti-iue.Si,. A418. NalO. s 4 - 0 3 2 .17.0 16% 17% 9.8 39.0 (calculated)18.2 16.1 1'7.3 8.4 40.0 (found)I n the formula of blue ultramarine, the whole of the sulphur isassumed to be in the state of polysulphide, whereas i t has been longknown that decomposition with acids liberates oxysulphur-compounds.The quantity of these present, however, is very small and variable.The author believes that these oxyeulphur-compounds are most pro-bably present together with this in chemical silicate combination ; andi t appears pretty certain that these oxidised sulphur-salts arise fromultramarine previously formed, and again decomposed in the burningprocess.These oxidised products can be forrried in quantity by sub-mitting to a too excessive oxidation ; and these likewise can only bepartially removed by tvnsliing.I n concluding the series of ultramarines poor in silica, a red and ayellow compound are mentioned, but these have not been closelystudied, although the corresponding individuals in the series rich insilica are well known.Of this latter series less is known than theone just described. The white ultramarine here is quite wanting;the green is less positively known, and even the bluc, as to purity,staiids behind the one poor in silica. The large quantity of' clay-residue may especially be pointed to as a reason for this. Set-tiug out for the series rich in silica, with a silicate, H6A12Si3012, orHzA12Si3010 + 2Aq (instead of kaolin, H2A12Si208 + Aq in the preced-ing series), then with perfectly similar changes as in the latter series,the formula of the blue ultramarioe rich in silica is obtaitled. Byremoval uf the 2Aq i n the above formula, and replacement of H2 byNa2, the formula Na,A12Si20,0 is obtained, which is to be regarded asthat of the rich silicate ignited with soda. Such a silicate can bINORGANIC CHEJIISTRY.11 1obtained by igniting a mixture of kaolin with the right proportion ofsilica and soda. By adding to this formula, 2Na2S, t h o type of theoriginal silicate formula is obtained, and this transformed expression,Na6AIzSi3010Sz o r NazA1,Si,Olo + 2Na2S, must be that of the unknownwhite ultramarine of the series, Attempts to prepare this by theauthor and Ritter led to bluish or greenish-blue products, which ap-peared to stand between the white and the blue ultramarines. Byabstraction of 3Na, from 2 mols. of the hypothetical white ultramarine,the formula of the blue rich in silica is obtained :-NalzA14Si60,0S4 - Na6 = Na,A1,Si60.zoS4.2(Na.,A1,Si30,,) +.2 S a 9 2(Na,hl,Si,O,,) + Saps4White ultramarine. Blue ultramarine.Blue Ultramarijie (rich in Silicu).Si,. Al,. Na,. 0 2 0 . s4.19.5 18.5 16.0 37.1 14.9 (calculated)19.0 12.7 17.4 37.3 13.6 (blue ultramarine)17.7 15.8 17.7 38-6 12-2 (bluish-green ultramarine)Now in this series, two products are found, natmcly, a red and ayellow compound. The first has only been recently prepared in thepure state, and was a t first only designated " violet ultramarine."I b now appears that the vapours of diferent mineral acids a t a tem-perature of 150" behave quite differently towards blue ultramarinefrom the aqueous solutions of the same acids a t temperatures below100". If, for example, dry hydrochloric acid gas be passed overheated blue ultramarine, with exclusion of air, there appears to be noaction ; but in presence of air or of other oxidising agents, the blueultramarine passes gradually into a violet, and with long-continuedaction into an intensely rose-red coloured substance, without libera-tion of hydrogen sulphide or other sulphur-acids in any considerablequantity.The whole of the sulphur of the blue ultramarine appearsto pass over into tlie new compound. On washing, sodium chlorideand some alumina pass into solution. Analjsis shows that the onlydifference between tlie washed and dried substance and blue ultra-marine, is that the amount of sodium has been diminished about one-fourth, and that the manner of combination of the sulphur has beenaltered by the passage of the white ultramarine of Ritter past thegreen to the blue, ie., a-sulphur is considerably diminished, b-sulphuralmost unaltered, c-, d-, and e-sulphur somewhat increased ( c - , t l - , ande-sulphur refer to the sulphur taken a t first to be as a and il, andso determiuable by the iodine method, but by slight subsequent decom-positions in the operations, &c., converted into oxidised sulphur corn-pounds.Thus the total sulphur would be LL and b + c + d + e). Theproportion of Sa : S b is exactly 1 : 4, viz., that of tho sodium penta-sulphide, Na,S5. From marly observations on the physical behaviourof the red ultramarine, especially in the grinding and washing, also inthe chemical fact of the solution of some alumina, i t is concluded thatthe chemical process in the preparation does not go quite smoothly,and that the best product yet obtained is still farther from the condi112 ABSTRACTS OF OBEMTCAL PAPERS.tion of chemical purity than the blue ultramarine.Theoretically,the red ultramarine is obtained by abstracting 8Na2 from the 5-foldformula of the hypothetical white (rich) ultramarine. It may also bcobtairied by abstraction of Na2 from the :,-fold formula of the blue(rich) ultr&narine :-Na,30A1 1o Si,, OjoSl0 - Nitl65 (Xa2A~2si301u + ZNa28)White ultramarine (rich in silica),Na3,A120Si300~&320 - Na,5[2(Na2A12Si30,0) +. N%s41Blue ultramarine (rich in shca).SI5. Mia. Nai4. 05,.19-7 12.8 15.0 37.520.2 13.5 12.9 37.918.5 13.8 14-1 37.0- Na14AlloSiI,0MSlo.5(Na2A&Si3Ol,) i 2Na2S5Red ultramarine (rich in silica).- - Na2&~0Si3001~S202[5(Na2AlpSi30101. + .2IVaf3,]Red ultramarine (rich in sahca).SlO.15.0 (calculated)15.5 (violet, Niirnberg)16.3 (red, of Buchner)Yellow ultramarine is obtained with the red as an accidental product,but recently Griinzweig has found a sure method of preparing of itfrom the red ultramarine.A formula can be derived from that of theblue ultramarine (rich), by abstracting one-fourth of the sulphur, andadding oxygen equivalent to the total sulphur in the blue ultramarine,thus :-Na6A14Si6020S4 = 2(Na2AI2SisOI0) + Na2&Blue ultramarine (rich).Na6A14Si,0zrS3 = 2(Na2A1,Si30,,) + Na,S304.Yellow ultramarine (rich).Na6fi14Si,0zlS, = Na,A14Si6020S~ - s + 04.Yellow Ultramarine (rich in silica).Si,.Al,. Na6. Op4. s3.18.8 12.1 15.4 42.9 10.6 (calculated)18.8 13-0 13.7 42.7 11.8 (found)The iiecomposition-products were only free sulphur and sulphuricacid, so that no iodine was required. This yellow ultramarine is, asGrunzweig shows, an oxidation product of blue.The following formulae are intended to show in their arrangement,&C.-(1.) I n what series of reactions ultramarine can arisefrom alumino-silicates by the known method of preparation.(2.) In what relation the different ultramarine compounds stand toeach other.(3.) How they join themselves to those groups of the mineralsilicates, which originally stimulated the artificial preparation ofultramarineIYORGASIIC CHE3IISTRT. 113Series poor in Silica.Kaolin.. ....................HZAl2Si2O8 + HZOKaolin ignited with soda ......White ultramarine .......... Na,Al2SiZO8 + NazSBlue ultramarine ............ 4(NazA12Siz08) + Na2$Na2Al2SiZO8Nosean. ................... 2(N~AlzSiz06) + Na?SOdFresh sodalite .............. 3( NaZA1,SizO8) + 2NaC1Hauyu.. .................. 2(:} AlZSi2O8) + Ez } zSO,2Series ~ i c h in Silica.Hypothetical root silicate ....The same ignited with soda . .Mesotype (natrolite) ........Decomposed sodalite ........Hypothetical white ultramarineBlue ultramarine ............Red ultramarine ............Yellow ultramarine ..........H,AlZSi3Olo + 2Hz0Na,AlzSi 3010NazA1zSi30,0 + 2Hz0NaZAlzSi3Olo (traces of NaC1)N~AI&i3010 + 2NazS.2(NaZA1?Si3Olo) + 2N,S45(NazA1,Si3010) + 2N&S52(NazAlzSi3010) + Na2S304 w.s.The Gadolinite-Earths. By C. MARIGNAC (Ann. Chinz. Phys. [ 5 ] ,14, 2471.-Working on about 300 grams of the mixed oxides, theauthor, following out the method of separation adopted by Bahr andBunsen, succeeded in separating the oxides into eighteen differentportions, passing from pure yttria on the one hand to pure erbia onthe other. The yttria and erbia present all the properties previouslyassigned to them by Bunsen and Bahr, and by other observers. Theoriginal mixture of oxides was of a pale yellow colour, and it wasfound that, whereas yttria is white and erbia is pale rose-coloured, theintermediate portions of the oxides were of a more or less deep yellowcolour as they mere further removed from erbia on the one hand,and from yttria on the other.The most deeply-coloured portionwas examined, with the view of settling t'he question, whether t'hiscolour is due to didymium or to some other oxide of the yttriumfamily.Its solution in nitric a8cid presented the absorption-spectra oferbium and didymium. By treat,ment wit'h potassium sulphate asmall quantity of didymium was separated, after which the absorption-spectrum of didymium was no longer visible, although the colour ofthe oxide had suffered no perceptible diminution. It must thereforebe concluded that the colour of this oxide is not due to didymium,since it WRS proved by experiment that a mixture of yttria and erbianeither prevents the precipitation of didymium nor affects its absorp-tion-spectrum ; and since neither yttria nor erbia is yellow, the colourof the oxide must be due to the third gadolinite-earth, t e r b i a , origin-ally distinguished by Mosander, and the existence of which was deniedby Bunsen and Bahr, and more recently by Cleve and Hoglund.For the separation of terbia in a state fit for examination, thoseportions of the mixed oxides must be taken in which traces only o114 ABSTRACTS O F CHEMICAL PAPERS.erbia exist. The oxides are dissolved in nitric acid, and subjected toa series of fractional precipitations with oxalic acid, the first portionsof precipitate being the richest in terbia.By this treatment thewhole of the yttria is separated, and the terbia obtained mixed onlywith didymium oxide and erbia.The didymium is separated in theusual way by means of potassium sulphate ; but for the separation ofterbia from erbia no method has yet been discovered. The molecularweight of terbia (mixed with erbia) is 116, and estiniating the amountof erbia at 6-8 per cent., and taking its molecular weight a t 129, thereal molecular weight of terbia must be about 11.5, which would makethe atomic weight of terbium either 99 or 148.5, according as theoxide is considered as a monoxide or as a sesquioxide. This atomicweight was confirmed by a determination made on pure terbia obtainedfrom the forinate (see next abstract).Terbium oxide, after moderate heating, is of a pure dark orange-yellow colour ; it is decolorised by heating in a current of hydrogen, orby simple exposure to a very high temperature ; in the latter case it isnot reoxidiscd by heating in contact with oxygen.This loss of colouris accompanied by an extremely slight loss of weight, as in the case ofdidymium oxide. Terbium oxide dissolves slowly, but completely, invery dilute acids, in hydrochloric acid with disengagement of chlorine.I t s salts are colourless, and have no absorption-spectrum.Terbium sulphate, Tb,( SO,), 8H20, forms colourless crystals, iso-morphous with the sulphates of yttrium, erbium? and didymium ; thecrystals lose all their water a t a low red heat, and their sulphuric acidat a higher temperature.The yellow mixture of oxides from the decomposition of the nitrates,which contained erbia in large quantities, was submitted to fractionalprecipitation with oxnlic acid.Rp this method the whole of theyttria may be separated and an oxide obtained, whose equivalent risesgraduallyby continuation of the above treatment. but the colour of whichnever attains the intensity of pure terbia, and even seems to diminishafter a time. The oxslate from this oxide has a decided rose colour,and its solutions show the erbium absorption-bands very plainly.This and the following faets seem to point to the existence of afourth oxide of this family.Although the yellow oxide obtained in the above experiment couldnot contain more than a trace of yttria, and although it containederbia to the extent of probably half its weight, its molecular weightwas only 117, which is much lower than would be expected of amixture in equal proportions of erbia and terbia, whose respectivemolecular weights are 129 and 115.Terbium formate, as stated by Delafontaine (next abstract), ismuch less soluble than the formates of yttrium and erbium. When,however, the author attempted to separate the above mixture of oxidesby this method, he obtained only a series of products differing butslightly in their molecular weights and depths of colour.c. w. w.Terbium and its Compounds, and the probable existence ofa New Metal in the Samarskite of N. Carolina. By N. DELA-EONTAINE (,4m. Chim. Phys. [5], 14, 238).-Terbium is most adIS ORGANIC CHEJIISTRT. 115vantageously extracted from samarskite, Fhich contains but smallquantities of yttria and of Bunsen’s erhia.The oxides precipitatedby means of potassium sulphate contain but little cerium, and probablyno lanthanum, the didymium being accompanied by terbium in somequantity. The mixed oxides were dissolved in nitric acid, arid repre-cipitated by potassium sulphate. The bases contained in the mother-liquor from t,his precipitate were combined with acetic acid, theacetate thus formed crystallisi~~g in colourless crystals, easily decom-posed by heat, giving a dark-orange oxide. Treated with formic acidthis oxide gave an indistinctly crystalline crust more soluble than theformates of the cerium metals, and the mother-liquor, evaporated todryness, intumesced greatly when heated, a character not exhibited bythe formates of lanthanum and didymium.The following process is the one finally adopted for the preparationof terbia.After separation of the cerium metals by potassium sulphate,the syrupy solution of the nitrates of the yttrium metals was mixedwith a saturated solution of sodium sulphate, and crystals of the samesalt were added until no more was dissolved. The crystalline depositthus formed furnishes a dark yellow oxide, that of the soluble sulphatebeing lighter-coloured.The nitric acid solution of the dark yellow oxide was fractionallyprecipitated by oxalic acid, and the least soluble portions of the oxy-late were converted into formate. The insoluble portion of theformate thus produced furnished a dark orange-coloured oxide ; byrepeating this treatment the percentage of base in the formate maybe raised above GO per cent.The solubility of the formate is about3.3 parts in 100 parts of water.The atomic weight of terbium is fixed provisionally a t 98, themolecular weight of the oxide being 114.Terbium formate is a white powder, or forms a strongly adherentnon-crystalline crust, soluble in about 30 times its weight of viater.When heated i t burns without intumescence. The acetate crystal-lises in mall, transparent, colourless prisms, much less soluble thanacetate of didFmium. It charsbelow redness, and burns like tinder.The slight solnbility of terbium formate, and the fact that i t is ex-tracted from a double sulphate insoluble in sodium sulphate, mightconfound terbium with lanthanum and didymium.The formation, onthe other hand, of the oxalate in presence of a large excess of nitricacid, excludes the possibility of the presence of an appreciable quantityof lanthanum ; moreover, the spectroscope shows only a trace of didy-inium. The absence of colour in the salts, and the difference of solu-bility of the formates, acetates, and sulphates of terbium anddidymium, also distinguish the two metals.The terbia described in the present, paper possesses the propertiespreviously recognised in Mosander’s erbia. This is seen in its hehs-vionr to acids ; its loss of colour when heated out of contact with air,and recovery of colour when heated in contact with oxygen ; its greattendency to form sub-salts insoluble in nitric acid, acetic acid, &c.The only important difference is the slightly higher molecular weight,which is probably due to the imperfect purity of the former product.Its formula is Tb(C2H,02), + 23 Aq116 ABSTRACTS OF CHEMICAL PAPERS.On the other E u d s of Snmars1iite.-As mentioned above, sodiumsnlphate separates the oxides of the Fttrium metals of samarskite intotwo portions, one of darker, the other of lighter colour.The mixtureof oxides was treated with hot formic acid diluted with a quantity ofwater calculated to dissolve the salts produced ; a white magma was,however, formed, which was not dissolved by addition of more hotwater. The liquid from this deposit yielded on evaporation, first,brilliant, well-defined rhomhoi'dal prisms, not grouped together ; theycontained 47 to 47.5 per cent.of a bright yellow oxide ; afterwards theliquid yielded longer prisms, arranged in fan-like groups ; these last,mixed with the dried mother-liquor, gave on heating, during whichthey intumesced greatly, rz light yellow oxide, which was put aside asrich in yttria. The first formates, purified by recrystallisation, con-version into oxalate, and digestion with nitric acid, contained a basewhose equivalent (molecular weight) varied between 89 and 91 Theoxide, divided into two portions, one of which was converted intoacetate, and the other into formate, gave on mixing a slightly solublewhite powder, the molecular weight, of whose base was also about 91.The dark-yellow oxides remaining after the extraction of terbiamere subjected to a repetition of the process foil the extraction of terbia,and the portions not precipitated by oxalic acid, treated in the abovemanner, gave a white crystalline powder, the molecular weight of whosebase was also about 90.The author has also observed a number of other circumstances,which lead him to believe in the existence of a new earth in samar-skite, besides those a1 ready described.c. w. w.Philippium. By M. DELAFONTAINE (Compt. rend., 87, 559).-In aprevious paper the author indicated the probable existence of a fourthearth in samnrskite. This new earth is intermediate in colonr andmolecular weight between yttria and terbia (YO = 74.5 : TbO = 114).Assuming that philippia is a protoxide, its equivalent is between90 and 95 ; it is easily obtained free from all but a small quantity offitria, and a somewhat, largeie proportion of erbia.Philippium formate crystallises easily, either on cooling, or by spon-taneous evaporation, in small shining rhomboidal prisms, less solublethan yttrium formate, which is deposited in nodular gronps from asyrupy solution ; terbium formate is anhydrous and soluble in 30-35parts of water.Sodio-terbic sulphate is scarcely soluble in water, thecorresponding philippiurn-compound is easily soluble. Philippiurnoxalate is more soluble in nitric acid than terbium oxalate, but less so-luble than the yttrium salt. Philippiurn nitrate becomes dark pellowwhen fused ; yttrium and terbium nitrates remain colourless.Philip-pium salts are colourless when pure; the oxide is decolorised by heatingin a current of hydrogen, or simply by a strong heat, becoming yellowagain on cooling in the air. Concentrated solutions of philippinmsalts give in the indigo-blue (X = 450 nearly) a wide and very intenseabsorption-band, with its edges, more especially the right, very -Re11defined ; this band is not seen in yttrium, erbium, or terbium solutions.I n the greon there are two rays, one belonging to erbium, the otherand less refrangible, probably to philippiurn ; finally, in the red there iINORUANIC CHEMISTRY 12 7a t least one narrow band. On directing the slit of the spectroscopetowards the sun, the author observed, with solutions of terbium, amoderately dark band in the violet (X = 400405 nearly) ; itsbreadth is about half that of the band characteristic of philippiurn, andi t seems to be entirely wanting in some specimens of terbia, othershaving merely a trace. The author doubts whether it is reallycharacteristic of terbium, and considers it possible that it may indicateanother new earth, whose atomic weight would be intermediatebetween those of erbium and terbium.He intends to study this ques-tion more fully, and also promises a comparative study of philippiurnThe Mosandrium of J. L. Smith. By M. DELAFONTAINE (Compt.rend., 87, 600) .-The author considers that Lawrence Smith’s mosan-drium is identical with the terbium which he himself described in arecent memoir (Ayzn. Chirn. Phys. [5], 14, 238) (see p.115). He claimsalso the priority of discovery, since “ mosandrium ” is but a mixtureof about 75-80 per cent. terbium with 20-25 per cent. of a mixtureDecipium, a new Metal fl- 3m Samarskite. By M. DELAFON-TAINE (Compt. ret~d., 87, 632).-In his researches on the samarskite ofN. Carolina the author has discovered a new metal, which he callsdecipium (from dec$iens, deceptive). This metal, which otherwisepossesses the properties characteristic of the metals of the cerium andyttrium families, forms an oxide whose molecular weight is approxi-mately 122 for the formula DpO, or 366 for Dpz03 ; it has not j e t beensufficiently separated from didymium to be able to show its truecolour ; its salts are colourless ; the acetate crystallises easily, is lesssoluble than the didymium salt, but more so than the terbium salt;decipio-potassium sulphate is but slightly soluble in a saturatedsolution of potassium snlphate, but easily soluble in pure water.Decipium nitrate gives an absorption-spectrum containing at leastthree bands in the blue and indigo.It is necessary to usedirect solarlight. The most refrangible band is a little narrower than that ofphilippium or the band rn of didymium; i t is tolerably dark; its middlecorresponds nearly with the wave-length 416, or with No. 195 on Lecoq’sscale ; it is approximately in the middle of the space between Fraun-hofer’s lines G and H, but a little nearer to G. Neither didymiumnor terbium gives bands in this part of the spectrum; the bandcharacteristic of terbium is more to the right, and nearly out of thespectrum given by ordinary light.Under exceptional circumstancesthe author observed the violet space beyond this band, and dis-tinguished two well-defined bands, probably H and H’.The second decipium band is narrower, more intense, and less well-defined; it is situated in the less refrangible blue, and its middlecorresponds with the wave-length 478 ; it is nearly in the same placeas one of the didymium bands, but is much darker. Finally, more tothe left, and nearer the limit of blue and green, there is an ill-definedminimum of transmission, which is possibly composed of two faintbands. Samarskite therefore contains the following metals :-and terbium compounds. c. w. w.of yttrium, erbium, and philippiurn.c. w. w.VOL. XXXYI. 118 ABSTRACTS OF CHEMICAL PAPERS.Name.Yttrium . . . .Erbium . . ..Terbium . . . .Philippium..Decipium ..Thorinum . .Didymium . .Cerium . . . .Colour of oxide.White.. . , , .Rose ., .. ..Orange ....Yellow .. ..White (?) ..White.. . . . .Brownish ..Pale yellow,CharacteristicMol. weight. absorption-band in A.YO = 74.5 NoneTbO = 114-1.15 400 (about)DpO = 122 41 6Tho,= 267.5 NoneDiO = 112-114 572-577Cz03 = 324 NoneEhO = 130" 520-522PpO = 90 449 7 7The atomic weights of some of these metals present a curiousrelationship :- Yttrium - 58Philippium = 74 or 59 + 2 x 8Terbium = 98 or 58 + 5 x 8Decipium = 106? or 58 + 6 x 8Erbium = 114 or 58 + 7 x 8If these metals are taken as trivalent (YzO,,T~O,, &c.) the dif-ference would be 12 or one of its multiples, instead of 8.c. w. w.Ytterbium, a new Metal from Gadolinite. By C. MARIGNACCompt. rend., 87, 578).-1n the course of his researches on thegadolinite-earths (Ann. Chirh. Phys. [ 5 ] , 14, 247) the author obtained,by the method there described, some quantity of an earth whosephysical and chemical characters and molecular weight were those oferbia. On continuing the process of separation by fusing the nitrate,he finds, however, that a further separation takes place, resulting, onthe one hand, in a rose-coloured earth presenting the characters oferbia somewhat intensified, and on the other hand, in a colourlessearth, of molecular weight = 131 nearly.The metal contained in this new earth the author names ytterbium;it presents the following characters :-Both the oxide and the saltsare colourless; the nitrate is decomposed by heat without coloration.Solutions of ytterbia give no absorption-spectrum, either in theordinary spectrum or in the ultra-violet (Soret).The earth itself isless easily attacked by acids than the other earths of this family. Itdissolves slowly in the cold, or a t a gentle heat in slightly dilutedacids ; on boiling, it dissolves easily even in acetic and formic acids.Ytterbium sulphate resembles, and is probably isomorphous with, thesulphates of yttrium and erbium; it dissolves easily arid withoutresidue in sulphate of potassium, no precipitate being formed even onboiling. A neutral and not too concentrated solution of ytterbiumchloride is not precipitated by sodium thiosulphate ; a very concen-trated solution, containing erbium, gives a precipitate containing a,larger proportion of erbium than is contained in the residual salts.Ytterbia precipitated hy potash, and submitted to a current of chlorine,dissolves completely in presence of excess of alkali.The farmate, Yb203.SC2H203.4Aq.,t.dissolves in less than its weight of* See Marignac's paper, page 119. t (P)CH203INORGANIC CHEMISTRY. 119water, and crgstallises in small crystalline nodules, resembling theformates of yttrium and erbium ; it is decomposed with intumescenceby heat, and loses its water of crystallisation at 100". All theseproperties prove the absence of thorinum, the only metal which couldbe present and could raise the equivalent.The existence of this new metal in erbia throws doubts on thecxactness of the equivalent of the latter, as determined by Bunsen andothers ; it would lead to the sopposition that t,he molecular weight oferbia must be lower than that usually given ; in facb, in the purestspecimen of erbia prepared (which still contains ytterbia) the mole-cular weight was between 122 and 126, the true molecular weight oferbia being probably lower even than this.Taking the molecular weight of ytterbia at 131, the atomic weightof ytterbium would be either 115 or 172.5, according as we adopt theformula YbO or Yb203 for the oxide.c. w. w.The probable Compound Nature of the Didymium fromCerite. By M.DELAFONTAINE (Compt. rend., 87, 634).-Didyminmobtained from cerite shows, as is well known, in the blue towards thegreen, a group of four nearly equidistant narrow bands ; the first andfourth (-1 = 482 and y = 469, Lecoq) are much better defined anddarker than the others. Sometimes the second, third, and fourth looklike a wide minimum of transmission, in the middle of which y appearsvery distinct. Didymium from samarskite never exhibits this groupof bands under any circumstances. It seems also that the band in theindigo-blue (which Lecoq calls m), whose middle corresponds with thewave-length 444, is always less intense in samarskite didymiurn thanin cerite didyminm.It might be conceived that the presence of terbium and decipium inthe didymium from samarskite would produce the above effects ; how-ever, when a solution of terbium was placed between the solutioii ofdidymiuni and the slit of the spectroscope, no effect was producedon the spectrum of the didymium.It would seem therefore that the didymium from cerite contains anew element, characterised by the above-mentioned absorption-bands,which are wanting in the spectrum from samarskite didymium.c. w. w.Pyrophoric Iron. By R. BOTTGER (Chem. Centy., 1878, 575).-Byheating iron tartrate, a pyrophoric mixture of carbon and ferrousoxide is obtained. A pyrophoric form of ferrous oxide, free fromcarbon, may be procured by heating iron oxalate in a small glassbulb. M. M. P. M.Cobalt-ammonium Compounds.By S. M. JORGEXSEN (J. yr.Chew,. [2], 18, 209--247).-1n the present communication the authorconsiders the chZoroy~~?yz~~eo-saZts : he has also succeeded in preparinganalogous series of bromopurpureo-salts and nitrato-purpureo-salts :he regards the xantbocobalt salts of Gibbs and Genth as belonging tothe nitro-purpureo series.-4 cid Chlo rop rirpu reocobnlt Su Zphate, ((31,. CoJ ONH3)?S O4 ( S04H) 6, isprepared by intimately mixing 1 mol. of purpureo-chloride with aboutk 120 ABSTRACTS OF CHEMICAL PAPERS.12 mols. of concentrated snlphuric acid, and after some time treating themixture with40 C.C. ofwater a t 70" for every 5 grams of purpureo-chlorideused. On filtering and leaving the filtrate to cool, largedark violetprismsare deposited ; they are collected on a funnel in the lower part of whichis placed a small cone of fine platinum gauze, washed with strongalcohol, pressed between paper, and dried over snlphuric acid.Thealcohol causes the precipitation of a small amount of a new salt(probably normal sulphate ; see below), but this is washed throughthe platinum gauze and removed.The crystals are very readily decomposed on the surface by water,but dissolve in warm water, with production of an acid liquid, fromwhich cobalt,ic oxide is not precipitated on long-continued boiling.Inasmuch as in this and the following chloropurpureo-salts the chlorinecannot be detected by the ordinary tests, the author regards the chlorineas intimately combined, probably with cobalt, whereas theothernegativeradicles are in more direct combination with ammonia.The chlorinehowever in this salt is partially precipitated on boiling with silvernitrate. Anhydrous normal sulphate mixed with hydrated sulphatecrystallises from a solution of the acid sulphate in hot water.Normal Chloropurpureocobalt Sulphate. - a. Hydrated Salt,C1,. (Co210NH3)2SOa.4Hz0. Prepared in a manner very similar to thatdescribed for the foregoing salt, only 6 mols. of sulphuric acid howeverbeing employed for each mol. of purpureo-chloride ; the crystals whichseparate on filtering and partial cooling are removed (see below), andthe second filtrate on complete cooling deposits nearly pure hydratedsulphate. The crystals are washed with cold water and pressed : theypresent rhombic forms, and are of a deep purple-red colour, withbrilliant lustre.This sulphate is soluble in 133.4 parts of water a t17.3", it is readily soluble in hot water ; the solution unless very dilute,deposits the anhydrous sulphate on cooling. 011 boiling with watercobaltic oxide is precipitated. b. Anhyd?.ous Salt, C12(Co,.10NH3)2S0,.-The crystals which separate on partial cooling of the first fil-trate (see above) consist of the salts a and b mixed : on exposure toair, a alone effloresces, and b may then be mechanically separated.This salt forms black or purple-brown octohedral crystals, which aremore slowly soluble in water than the hydrated salt : the solutionreacts as that of the latter salt.Chlorop?cr~ureocobalt Nitrate, C12(Co210NH3)4N03.-This salt ap-pears to have been prepared by Gibbs (Proc.A m . Acad. 1876, 11, 3),but the formula given by him is inconsistent with his own analyticalresults. It is best prppared by mixing the purpureo-chloridewith water and a little dilute sulphuric acid, treating the mass on afilter with water a t 50°, with addition a t intervals of a few dropsof sulphuric acid, and allowing the solution to flow into an excess ofconcentrated ice-cold nitric acid ; the crystals which form are washedwith nitric acid of sp. gr. 1.2 and finally with alcohol. The salt is solublein about 80 parts of water a t 16". By slowly heating the solution, thecorresponding roseo-salt is produced : on boiling, cobaltic oxide isthrown down. At.a temperature somewhat above 110" the saltdecomposes with violence.Chloropurpzireocobalt Hydrate does not appear to exist. ThINORQANIC CHEMISTRY. 121author attempted to prepare this salt by treating of 1 mol. normalchloro-sulphate with 2 mols. of barium hydroxide and water in thecold ; the filtrate reacted however as a mixture of roseo-cobalt chlorideand hydrate. Only roseo-cobalt hydrate was obtained ou treating pur-pureo-chloride with silver oxide and water.ChZoropuryureocobnIt Bromide, CI,( c0~10NH.~)Br~, may be preparedfrom the normal sulphate, or nitrate, by precipitating with sodium bro-mide, or from the carbonate, by precipitating with concentrated hydro-bromic acid. The salt is however best prepared from purpureocobaltchloride by a process analogous to that used for the preparation of thenitrate, the liquid being allowed to flow into cold concentrated hydro-bromic acid, in place of nitric acid ; the precipitate is washed withhydrobromic acid and finally with alcohol. This salt crystallises inoctohedral forms resembling the purpureo-chloride, but of a more violet-red colour than that salt.It is soluble in 214 parts of water a t 14.3".The author regards Clandet's salt ( 10NH3.Co2)Br6 (Chern. SOC. Qu. J.,4, 361) as probably a bromide belonging to the roseo series.Clilo?.oyu,y~6reocobult Iodide, Cl,. (Co210NH,)I,, is best preparedby a method similar to that employed for the preparation of thebromide : it crystallises from hot water containing a little hydriodicacid in large dark brownish-violet octohedroris : it is soluble in 54.4parts of water a t 15.6".By treating a solution 01 this salt with iodinefor some time, or by acting on the chloronitrate with iodine dissolved inpotassic iodide, or by adding a hydriodic acid solution of iodine to anaqueous solution of the chloropurpureocobalt carbonate, brown metal-lic-like needles separate, which exert a powerful polarising action onlight. These crystals could not be obtained perfectly pure ; they aresupposed by the author to be chloro~~ulpi~reocobalt periodide.Chloropurpureocobalt. mewuric Chloride, Bromide and Iodic1e.-Bytreating purpureo-cobalt chloride with excess of mercuric chloride,Claudet, Carstanjen,and Gibbs obtained a salt with6 mols. of HgCL Thesame salt is obtained by using sodio-mercuric chloride, NaHgCl,, orNa4HgCl6: the author shows that this salt is a member of the chloro-purpureo series, and that the hydrated salt (with 4H20) prepared fromroseo-cobalt chloride is a member of the roseo series. He proposesfor the latter the formula (Co,.lOHN3)(HgCl3),'4-H:,O where HgC& =Hg=CI-ClICl- and the fcrrnula C12.( Co2.1ONH3) ( Hg3ClB)i' for theformer, where Hg3CI, = Hg< cl~cl-Hg-cl~cl- When a mode-rately warm aqueous solution of purpureo-chloride containing a littlesulphuric acid is mixed with an aqueous solution of Na2HgBr4, largeviolet-red needles slowly separate. This salt is regarded by the authoras having the complex forrula-ClZCl-Hg- C1= Cl--'C12(Co210NH3) { ~ ~ ~ ~ } (10NH3.Coz)C12.By substituting a solutionof potassium iodide, saturated a t 70" withmercuric iodide, for the double sodio-mercuric chloride, in the pre-ceding process, a salt separates immediately in brownish-yellowneedles, which, when quickly waslied with cold water in the dark, andpressed, give numbers agreeing with the formula C12.( Co210NHJ(HgI,) 122 ABSTRACTS OF CHEMICAL PAPERS.Another salt containing mercury and iodine may be prepared 13-j decom-posing a solution of the normal chlorosulphate or nitrate with potassiumiodide solution, and then adding ail aqueous solution of potassiomer-curic iodide, KaHgT4 ; after some time large brilliant brown plates sepa-rate.This salt appears to have the formula CI?.( Co?10NH,)(Hg14)2”whereHg14 = -l=I-Hg=I-.I t is alwnjs more or less mixedwith the iodide already describtd.Chl oropu rpu reoco bal t-p la tinic Bromide, C 1 ( Coal ONK,) (P t B re) ?. Thissalt, which is the analogue of the platinic chloride salt prepared byClaudet, as also by Gibbs and Genth, separates in the forin of ayellow-brown crystalline precipitate, from a moderately warm mixtureof the chlororiitrote and potassioplatinic bromide, both in aqueonssolution. I t is sparingly soluble in cold water. The crystalswhich separate from a mixed solution of the purpureo-cobalt chloride,or nitrate, and tin chloride, or tin-ammonium chloride, are shown toconsist of purpureo-chloride only, and not to be a double cobalt saltcontaining tin chloride, as supposed by Gibbs aiid Genth (Sill.Am.J. [IS], 23, 264). Similarly purpureo-cobalt bromide separates from amixed solution of the chloronitrate and potassium-zinc bromide.Chloro~?~s.pureocobaZt SiZicqfEicoritle, C1,( Co,.lONH,)( SiF6)?. Thissalt, which has been described by Gibbs (Proc. Am. Acad. 11, 9), maybe readily produced by adding a cold solution of any chloropurpureocompound,. preferably the nitrate, to excess of concentrated aqueoushydrofluosihcic acid. The crjstals are dichroic, and separate in rhom-bic plates; they are regarded by the author as without water ofcrystallisation. The formation of this salt may be used as a very delicatetest for silicic acid in presence of hydrofluoric acid. It is onlynecessary t o add 1 or 2 C.C. of a cold concentrated solution of chloro-purpureocobalt nitrate to the suspected liquid: if 1 per cent.ofsilicic acid be present, crystals of the double salt separate a t once ; withsmaller quantities of silicic acid the crystals separate only after sometime. If necessary, the crystals may be washed with alcoliol andexamined under the microscope. The author has thus detected withcertainty 1.6 mgram. of silicic acid in preseice of 305 gram of 39 percent. hydrofluoric acid.Cl~lor.opurpureocobalt Dithionate, CI,.( Co,lONH,)( S,O,),. - Thissalt separates as large, brilliant, violet prisms on mixing st cold aqueoussolution of the purpureochloride with sodium dithionate. This salt issparingly soluble in cold, more readily in hot water.ChZoro~urpureocobaZt Thiosulphcrte, C&.( Co,10NH3) (S,O.,)?, preparedby precipitating a cold solution of the pnrpureochloride with a solutionof sodium thiosulphate.The salt crystallises in rhombic €arm, OOP.ern , of a brownisl -red colour : it is insoluble in cold and only slightlysoluble in warm water.Chl,,l.op7sipzcreocol~(~lf Chyoniate, CI,(CO,~ONH~)(C~O~)~ and Dichro-n7crfe, C ~ , ( C O , ~ O N I - ~ ~ ) ( C ~ ~ O ~ ) ~ . The fornier salt is obtained in the formof a reddish or flesh-coloured crystalline powder, by mixing cold solu-tions of the normal chlorosulphate, nitrate, or purpureochloride andpotassium chromate. For the preparation of the dichromate, potassiumdichromate solution is employed, arid the temperature of the sulphateor nitrate solution is slightly raised ; if purpureo chloride be employeINOROANlC CHEMISTRY.123the solution must be cold. So soon as crystals form, the mother-liquormust be drained off, and the crystals quickly washed with cold water,and dried over oil of vitriol. If the crystals be allowed to staud for 24hours or so in contact, with a large quantity of wash-water they becomemuch altered in form and appearance, but on analysis little or nochange in composition crtn be detected. Chloropurpureocobaltdichromate crystallises in brilliant golden scales, which are somewhatsoluble in water. The author's results coucerning these chromatesalts are not in keeping with those of Braun (Gottingen, 1862).C/~Z~ro~ur~ui.cocobalt Carbomte, C12,( Co210NH3) (CO,),, crystalliseswith 9 molecules of water in large beautiful violet-red crystals, andwith 1 mol.of water in small 6 or 4-sided prisms of a darker violetcdlour. The former salt is obtained by rubbing together purpureo-chloride and excess of moist silver carbonate, filtering after a fewminutes,at once adding alcohol until a faint turbidity is produced, leavingthe solution to crystallise, and washing with alcohol of 50" (Twaddell).If the silver carbonate and purpureochloride be allowed to remain forsome time in contact, or if alcohol be not added to the filtered liquidvery shortly after filtration, roseocarbonate is produced. By dissolvingthis salt in water after efflorescence, and adding alcohol until a distinctturbidity is produced, the salt with 1 mol. of water is obtained. The%hydrated salt effloresces rapidly ; it is very soluble in water, producinga deep cherry-red liquid with alkaline reaction.C/Lloro232irpureocob,r2t Oxnlate, C1,( Co213NHL,) ( C204)2, and AcidTnrtratp, CI,( C0210NH3) ( C4H,0,),5H,0.-The former salt was ob-tained by Gibbs and Gclnth (Sill.Am. J. [ 2 ] , 23, 320). Thesechemists, however, overlooked the presence of chlorine in the salt.Krok gave the formula adopted above, which was admitted to be thetrue formula by Gibbs (Pruc. Am. dcnd., 11, 4). By using the chloro-nitrate as starting point in the preparation, the author has repeatedlyobtained crystals of the same composition. Gibbs (Zoc. cit.) says thatthe composition of different preparations varies considerably.The acid tartrate is prepared by adding a considerable excess of anaqueous solution of tartaric acid to the chlorocarbonate, followedby addition of alcohol.This salt crystallises in large brilliant violet-red needles, which are tolerably soluble in water, forming a liquid withan acid reaction.Chlo1'023ur~.ylL,.eocoBalt Pyropliosphde, C12( Co210NH3) ( P207H2)2, andC1,.(Co210NHJ) P207.zH,0.-'l'he acid salt is prepared by precipitatinga n aqueous solution of the chloronitrate with sodium pyrophosphateand a little free pyrophosphoric acid. The salt crystallises in massesof brilliant violet-red needles : i t dissolves with difficulty in water,forming an acid liquid, from which silver nitrate precipitates silverpyrophosphate, but no silver chloride.The neutral pyrophosphate is prepared by adding water just sufficientfor solution to a mixture of 1 molecule of the chloronitrate and rathermore than 1 molecule of sodium pyrophosphate, filtering a t once, andadding alcohol in small successive quantities until the greater part, ofthe salt has cryst,allised out : t h e crystals are washed with alcohol anddried in the air.This salt crystallises in long thin needles of a violet-red colour, containing from 3 to 4 molecules of water124 ABSTRACTS OP CHEMICAL PAPERS.Braun (loc. cit.) and Gibbs (Proc. Am. Acad., 11, 6) failed to obtainthe neutral chloropyrophosphate.Chloropurpureocobalt Diphosphopentamolybdate. - The acid salt,C&.( Co,10NH3) ( 5Mo03.2P04H) and the neutral ammonium salt,C12(Co210NH,) (5Mo03.2P04NH4) have both been prepared ; the formeras a rose-red crystalline powder, by precipitating a cold solution of thepurpureochloride with a solution of molybdic acid in excess of phos-phoric acid ; and the latter by using a solution of the correspondingammonium phosphomolybdate as precipitant.I n a note appended to his paper the author states that he has pre-pared a few chloropurpureo-clzyomium salts, e.g., C1,( Cr2.1C)NH3) C14, &c.,and has obtained results indicating the existence of a series ofLuteo- and also of Roseo-ohromiurn compounds.M. M. P. M.Double Salts of Cuprous Thiosulphate. By F. KESEL (Deut.Chenz. Ges. Ber., 11, 1581--1586).-The author has shown in a pre-vious paper (this Journal, 1878, 113) that the composition of theyellow salt which is formed by mixing together solutions of ctipricsulphate and sodium thiosulphate, is dependent upon the temperatureemployed.At 10" it has a composition quitie different from that of'the saltwhich had been prepared a t -10" ; and on decreasing the temperaturestill further, light yellow crystals separate, which dissolve to a colour-less solution in ice-cold water. It appears, therefore, that at a tem-perature under -lo", soluble double salts only are formed, and thesemost probably contain a larger proportion of sodium thiosulphate.Siewert's formula for the yellow salt, Na$3,03.Cu2S203.CuS, is defi-nitely confirmed. This salt can be easily prepared if the solutionsmixed a t the ordinary temperatures be kept a t 0" whilst the salt isseparating.The proportion of cupric sulphate and sodium thiosul-phate required to form the compound, Na&&03.Cu2S203.CuS, wasfound by several methods of examination to be as 2S,O3N~.CuSO4,and not in the proportion of 5S203N~.SCnS0,, as stated by Siewert.The yellow salt, when anhydrous, dissolves in concentrated hydro-chloric acid to a deep brown colonr, whereas the freshly prepared andmoist salt is couverted into a white insoluble powder, as describedin the author's previous paper. This marked distinction between thetwo compounds is ascribed to their difference in hydration. Alcoholprecipitates a light brown powder from the brown acid solution ; thesupernatant liquid contains cupric chloride. The analysis of thebrown powder (dried over sulphuric acid) showed it to be a thiosul-phate, and gave numbers corresponding with the formula,[ (S203)2CuzNa2] (GUS),. A. J. C.Decomposition of Lead Sulphate by Sodium Chloride,By F. MATTHEY (Arch. Pharnz. [ 3 ] , 13, 233--241).-A mixture oflead oxide, lead sulphate, and sodium chloride is found to react,producing lead chloride, the amount of lead chloride formed being indirect proportion to the lead oxide present, but in an inverse proportionto the sodium chloride ; the whole of the lead sulphate may, however,be removed from the mixture by repeated treatments with sodiuMINERALOGICAL CHENISTRY. 125chloride. Owing to the lengthened exposure of the above mixture tothe air, carbon dioxide was absorbed, and this caused the formation ofa chlorocarbonate, Pb,CI,CO,.Mechanical Purification of Mercury. By G. VULPIUS (Arch.Phurm. [3], 13, 231).-Mercnry is freed from dirt by causing it to passthrough a thick filter, in which several holes have been pierced by aneedle. E. W. P.E. W. P.Atomic Weight of Iridium.-By C. SEUBERT (Reut. Chem. Ges.Ber., 11, 1767--1772).-The author has determined the atomic weightof iridium (l), by estimating the amount of iridium in iridium ammo-nium chloride ; and (2) by estimating the iridium and the potassiumchloride in iridium potassium chloride. The number 192.744 wasDouble Salts of Dyad Iridium, By C. SEUBERT (Deut. Cherri.Ges. Ber., 11, 1761-1 767) .-In separating iridium from rhodium bymeans of hydrogen sodium sulphite, by Bunsen’s process, the followingdouble salts were obtained, viz., IrSO3.3N~~,SO, + 10HzO, cream-coloured scales.; IrH,( S03),.3NazS0, + 4H20, broad white needles ;and IrH2(S0,),.3Na,S03 + 10H20, in thin white needles. These saltshave an acid reaction ; they are almost insoluble in cold water, andare decomposed by hot water and by acids.When aqueous sulphurous acid is heated with iridium-ammoniumchloride to 70”, an olive-green solution is formed (reddish-brown bytmnsmitted light), which deposits a green crystalline powder on eva-poration. From the aqueous solution of this compound dark greenneedles (brown by transmitted light) separate out, having the corn-position, Ir2C16.6NH4C1 + 3H,O. On cooling down the concentratedmother-liquor to a low temperature, an acid having the composition,Ir.C12. SOsH2.4NH4CI, is obtained in orange-coloured needles. It is verysoluble in water, but is not deliquescent. It decomposes alkaline carbo-nates, forming salts. Its ammonium salt, IrCl,.SO,(NH,),.2NHrlCl + 4H20, crjstallises in rhornbic plates, and the potassium salt,,IrCI,S03Kz.2NH,C1 + 4Hz0, forms small red crystalline scales.obtained as the mean of 15 experiments. w. c . w.w. c. w