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INORGANIC CHEMISTRY. 443

I n o r g a n ic C h e mi s t r y.

Composition of Atmospheres which Extinguish Flame. By FRANKCLOWES ( PTOC. Roy. Soc., 1894, 56, 2-6) .--The experimental flame burning at a platinum jet 1 mm. in diameter, was 0.75 in. in height; it was gradually lowered into a cylinder containing the atmosphere of mixed gases, and these were considered to be in extinctive proportions if the flame was extinguished during its downward passage, or immediately on attaining its lowest position in the cylinder. The gaseous mixture was regarded as containing the minimum quantitr of extinctive gas, when the flame on being lowered into another mixture containing 1 per cent. less of such gas continued to burn in it for a few seconds before being ex- tinguished. Experiments made with flames of and Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. alcohol, varying from 0.4 in. to 1.5 in. in height, show that the varying dimensions of the flame are without influence on the proportion of carbonic anhydride in the air necessary to pro- duce extinction. Characteristic differences were observed between the behaviour of wick-fed flames and that of gas-fed flames when they were introduced into an atmosphere which extinguished them, the wick-fed flames gradually diminishing in size until they vanished, whilst the gas-fed flames gradually increased in size, becoming paler and apparently lower in temperature until they suddenly expired. The results of the experiments, of which a table is given in the original paper, show (1) that the extinction of a flame is not deter- mined simply by the proportion which the inert gas bears to the oxygen of the atmosphere into which it is introduced, but that the nature of the inert gas present also influences the result. (2) Carbonic anhydride exerts a more powerful extinctive effect on flame than nitrogen does. (3) There is a remarkable uniformity in the proportions of inert gas, which must be niixed with air in order to just extinguish wick-fed flames ; but this uniformity does not apply to the flames of combustible gases burnt from a jet. (4) The flames of gases burnt from a jet show no simple relation, as regards the proportion of oxygen present View Article Online

444 ABSTRACTS OF CHEMICAL PAPERS,

in the extinctive atmosphere, tJothe relative proportions of oxygen re- quired for their complete combustion. In the presence of the hydrogen flanie carbonic anhydride does not suffer partial deoxidation. The introduction of a minimum of 15 per cent. of carbonic anhydride into air is necessary to cause it to extinguish ordinary wick-fed flames. For the extinction of coal-gas flames, however, the addition of 33 per cent. of carbonic anhydride is necessary, and for the hydrogen flanie 58 per cent. E. C. R. Preparation of Perchloric and its Use in the Esti- mation of Potassium. By D. ALBERTKREIDEE (Zeit. anorg. (!hem., 1895, 9, 342-348).-Sodi nm chlorate is converted into pef- chlorate by cautiously heating during 1;-2 hours, the residue being dissolved in water, and hydrochloric acid added in quantity suficient to decompose any unaltered chlorate ; the solution is then evaporated to dryness, stirring vigorously towards the end of the operation, as otherwise the perchlorate retains some water and solidifies so that it cannot be removed from the dish. The finely pulverised residue is treated with concentrated hydrochloric acid, filtered from the sodium chloride, and well washed with hydrochloric acid, which is then re- moved from the solution by evaporation. The perchloric acid is sufficiently pure for the determination of potassium, for the slight residue obtained when it is evaporated is completely soluble in alcohol (97 per cent.), and consists of sodium perchlorate. If the sodium chlorate contained potassium chlorate the pulverised crystals of chloride and perch!orate are treated with alcohol (97 per cent.), which dissolves the latter more readily than the former, the alcohol is removed, and the residue treated with hydrochloric acid as above. The solubility of sodium perchlorate in alcohol (97 per cent.) is 0.2 grain per C.C. The preparation of perchloric acid, including the separation of the potassium salts, occupies about two days ; 100-300 Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. grams of sodium chlorate may be conveniently employed. For the estimation of potassium, the substance, which must be free from snl- phuric acid, is dissolved in hot water (20 c.c.), perchloric acid (1.5 times the theoretical quantity) added, and the solution evaporated to a SSrup, stirring constantly. It is then again dissolved in water and evaporated, the residue being washed twice with about 20 C.C. of 97 per cent. alcohol containing 0.2 per cent. of perchloric acid, the alcohol is decanted through an asbestos filter, the crystals dissolved in hot water (10 c.c.) containing a little perchloric acid, and the solutioii again evaporated to dryness ; the residue is finally washed on to the filter with the smallest possible quantity of the alcoholic perchloric acid, treated once with pure alcohol, dried at 130°, and weighed. The alcoholic washings shotild not exceed 50-70 C.C. The removal of is unnecessary, but if if is present the potassium perchlorate should remain in contact with perchloric acid. iii excess, before treating with alcohol. The analytical results are satisfactory. J. B. T. Density of Nitrogen. By LORDRAYLEIGH (Proc. Roy. XOC.,1894, 55, 340-344) .-In a previous paper (€'roc. Roy. SOC.,53, 146), the View Article Online

INORGANIO OHEMISTRY. 445

author has shown that nitrogen prepare‘d by Lupton’s method is lighter, by about 1/1000 part, than that derived from air in the usual way. It is now shown that nitrogen derived entirely from chemical compounds is materially lighter than atmospheric nitrogen. This difference amounts to about 1/200 part of the whole. Mean density. Nitrogen from nitric oxide by hot iron...... 2.30008 Nitrogen from nitrous oxide by hot iron ...... 2.29904 Nitrogen from ammonium nitrite by hot iron . .. . 2.29869 Atmospheric nitrogen by hot copper (1892) .. ,. .. 2.31026 Atmospheric nitrogen by hot iron (1893)...... 2.51003 Atmospheric nitrogen by ferrous hydrate (1894). . 2.31020 Experiments have proved that the densities do not alter when the gas is exposed to the Bilent electric discharge. The author demon- strates that the lightness of the nitrogen from chemical compounds cannot be due to the presence of impurities such as hydrogen, ammonia, water vapour, &c. J. J. S. Reduction of Nitric Oxide by Moist Iron or Zinc. By PAUL SABATIER and J. B. SENDERENS (Compt. rend., 1895,120,1158- 1161).-Nitric oxide in contact with moist zinc turnings over water is at first reduced to a mixture of nitrous oxide and nitrogen with a, small quantity of hydrogen. If the action is allowed to continue, the proportion of nitrous oxide diminishes, whilst that of nitrogen and hydrogen increases, the gas finally being a mixture of nitrogen and hydrogen only. The hydrogen is doubtless a result of the action of the ammonia on the zinc. In contact with moist iron, standing over mercury, the nitric oxide is reduced to a mixture of nitrous oxide and nitrogen, in the pro- portion of 2 vols. of the former and 1 rol. of the latter, with a

Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. small quantity of hydrogen, which results most probably from the action of the iron on the water in presence of mercury. The reduction of the nitric oxide takes place slowly, probably because of its slight solubility in water. A solution of the gas in ferrous sulphate solution is much more rapidly reduced, and the gas produced consists at first of 2 vols. of nitrous oxide with 1vol. of nitrogen, but after a the the proportion of nitrous oxide diminishes and that of nitrogen increases, whilst hydrogen is also given off in gradually increasing proportion, until at the end of the action the gas is a mixture of nitrogen and hydrogen only in practi- cally equal volumes. The iron becomes covered with hydrated ferroso- ferric oxide. Similar result8 are obtained with zinc. C. H. B. New Polyphosphoric Acid, H,P,O,,, and its Salts. By FRITZ SCHWARZ(Zeit. awry. Chem., 1895, 9, 249-266) .-Salts of tetraphos- phoric acid have been described by Fleitmann and Henneberg (Anna- Zen, 65,322), the sodium salt being obtained by melting the anhydrous pyrophospliate with hexametaphosphate. It crystallises with 36H20. Fleitmann and Henneberg’s acid tetraphosphate, Na4H2P40,,,is formed from the salt Na,H2P207by the removal of the water of crystalli- sation. VOL. Lxvm. ii. 34 View Article Online

446 ABSTRAOTS OF CHEMIOAL PAPERS. is best obtained by melting 100 grams of the pyTophosphate with 50-55 grams of metaphosphate ; after keeping it in a fused state for about 15 minutes, it is allowed to cool slowly, and the product is broken into small pieces and cautiously dissolved in cold water. The solution, allowed to remain all nigbt, is filtered, and the filtrate evaporated spontaneously ; the crystals which are deposited can be recrystallised from cold water, but great care is necessary, as the heat developed on treating them with water is sufficient to partially convert the salt into metaphosphate. It crystal- lises from water with 16H20 in transparent crusts, loses water on exposure to air, and is very soluble. The solution has a faintly alka- lirie reaction; when boiled, it is quickly converted into pyrophos- pbate, whilst with mineral and some organic acids it yields pyrophosphate in the cold, and also orthophosphate when heated with them. The solution gives no precipitate with magnesia mixture until strong ammonia is added, which cont-erts the salt into orthophos- phate. Tiiphosphoric acid gives precipitates with salts of the heavy metals only in very concentrated solutions, and is then only partially precipitated, whereas is completely precipitated by salts of the heavy metals even in dilute Bolutions. The reason of this characteristic behaviour of triphosphoric acid lies in the forma- tion of double salts ; these separate in well-formed crystals from con- centrated solution of the sodium salt and the salt of the heavy metal. The free acid obtained from the copper salt br means of hydrogen sul phide is quickly converted, in aqueous solution, into pyrophosphoric mid, and consequently albumin is not coagulated by the solution. If however, a. few drops of acetic acid are added to a solution of the sodium salt, the triphosphoric acid in the nascent state will coagulate albumin. Cobalt sodium triphospkate, CON~,P,O,~+ 12H20, is obtained by

Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. adding a solution of a cobalt salt to one of sodium triphosphate of such a strength that no precipitate irJ formed, and then evaporating the mixed solution in a vacuum ; it crystallisev in beautiful, lustrous, rose-red crystals, which when dehydrated turn blue, and melt, at a red heat to a clear blue glass. It is insoluble in water, but easily soluble in acids, by which, however, it is not decomposed. A salt of the composition $Co0,Na20,SP,05, is obtained as a rose-red precipitate on adding cobalt sulphate (1.5-1.79 grams) to sodium triphosphate (1 gram) dissolved in the smallest possible quantity of water ; it contains 29-3:3 per cent. of water. Nickel sodium triphosphate, NiNaAP3O,, + 12H20, obtained in a similar way to the cobalt salt, forms green crystals which turn yellow when heated, and melts at a red heat to a brown glass. These nickel and cobalt salts crystallise in rhombic prisms and are isornorphous. Copper triphosphate, 5Cu0,3P205+ 13H20, is obtained by precipi- tating the sodium salt with copper sulphate in concentrated solution. Lead triphosphate, 6Pb0,4P20,, is obtaiued as a white precipitate which dissolves in an excess of the sodium salt; at a high tempera- ture it melts to a white glass. The precipitate of this salt is always mixed with lead tetraphosphate. Barium triphosyhate and calcium triphosphate, obtained by adding View Article Online

INORGANIC CHEMISTRY. 44 7

barium chloride and calcium chloride respectively to the solution of the sodium salt, form thick, flocculent, white precipitates. Zinc sodium triphosphate, 4ZnO,Na20,3P2Os + 19H20, is very similar to the cobalt and nickel salts ; it is obtained from coucentrated solutions as a white, crystalline powder, and from dilute solutions in beautiful, prismatic, colourless crystals. At a high temperature, it melts to a colourless glass. E. C. R. Reduction of Silica by Aluminium. By V1c;oui:ous (Compt. rend., 1895,120,1161-1164).-When tinely powdered silica (3 mols.) and finely powdered aluminium (4 atoms), previously freed from grease, are heated together, there is brilliant incandescence, the silica is reduced, and, after successive treatments with hydrochloric, sulph- uric, and hydrofluoric acids, amorphous silicon is obtained. Crystallised silicon is obtained on heating silica and aluminium in an electric furnace. If the aluminium is in excess, the silicon dis- solves in it; if the silica is in excess, the silicon forms the lower layer in the carbon crucible, or partly fuses and partly distils if the tube furnace is used. It can also be obtaincd in large quantity by heating a mixture of silica and aluminium with potassium silico- fluoride in a carbon crucible in a Perrot furnace. By whichever method it is obtained, crystallised silicon forms thin, hexagonal lamella?, which are sometiines very thin, and then are transparent, and have a yellow colour, bnt do not act on polarified light. The chemical properties of the crystallised silicon are identical with those of the amorphous variety (this vol., ii, 263). C. H. B. A Remarkable Change of Structure in Glass when Heated. By ED.P~IWOZNIK (Zeit.anorg. Chent., 1895,9,289--290).-The adthor describes the exfoliation which some specimens of soda glass undergo when heated. Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. Molecular Weight of Mercurous Chloride. By MICHELEFILETI (Gazzetta, 1895, 25, i, 88-94).-A polemical paper replying to V. Meyer (this vol., ii, 46), who has already published his answer (this vol., ii, 166). W. J. P. Crystalline Aluminium Chloride. By L. 31. DENKIS(Zeit. anorg. Chern., 1895, 9, 339--34l).-In order to obtain crystalline aluminium chloride, commercial anhydrous aluminium chloride is dissolved in water, and, after being filtered through glass wool, is mixed with concentrated hydrochloric acid, and the solution, cooled with a freezing mixture, is saturated with dry . The crystals which rapidly form are washed by decantation with concentrated hydrochloric acid until free from iron, and the excess of acid is removed as far as possible by the aid of the pump. The crystals are then placed on porous tiles and exposed to the air until free from hydrogen chloride ; in moist air, water is absorbed, but if kept at 20' their weight becomes constaut after about 48 hours. The crystals, A1C1,,6H20, do not change when kept over sulphuriz acid, lout if heated in a stream of dry hydrogen chloride, a basic salt 34-2' View Article Online

44s ABSTRACTS OF OHEMICAL PAPERS. is formed. Crystals may be obtained by adding concentrated hydro- chloric acid to cold, concenti-ated, aluminium chloride solution, hut t.liey are very small. The larger crystals, which are fully described, consist of hexagonal prisms of the second order, bounded by rhombo- hedrd faces, a : c = 1 : 0.5356 ; p : r = 62O 54' ; T : T = 54' 12'. The refractive index = about 1.6; the donble refi-action is strong tv-~= 0.053. J. B. T. Preparation of Stannic Bromide. By RICHARDLORENX (Zeit. czizoq. Chem., 1895, 9, 365--368).-Tin, in pieces 2-3 cm. long, is placed in a distillation flask, closed at the top with a cork fitted with a separating funnel drawn out to a capillary point; the funnel is filled with bromine, which is added to the tin so slowly that the tem- perature remains at 33-59', and the side tube does not become filled with bromine vapour ; the action proceeds quietly. When the greater portion of the tin has disappeared, the contents of the flask are distilled ; the first few drops contain a little bromine, but that which subsequently passes over is pure stannic bromide. It boils at 201", is colourless, readily forms crystals, and fumes slightly on exposure to moist air. The bromide may be stored in a corked flask ; if this is heated to about 40°, the bromide readily melts, and can be with- drawn in any desired quantity. J. B. T. The two Modifications of Stannic acid. By BICHARDLORENZ (Zeit.anorg. Chent., 1895, 9, 369-;33l).-A historical account of the in\-estigation of stannic acid and metastHnnic acid is given; the wradual and almost equal loss of water by both compounds under a.similar conditions is confirmed, proving that their composit.ion is identical, and that both exist in all degrees of hydration, from HISnOI to H,Sn03. The compounds retain their characteristic properties after repeated precipitation from salts or solutions, and their salts Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. cliffer. Recently prepared aqueous solution of stannic chloride or bromide is identical with that formed by dissolving stannic acid in hydrochloric acid or hydrobromic acid respectively. Aqueous stannic chloride solution gradually changes when kept, and the course of this change may be followed by means of potassium ferrocyanide; it consists in a progressive decrease of the tin ions. Aqueous stannic bromide solutions gradually deposit a white gelatinous precipitate, and the change which takes place in the solution appears to proceed 1 regularly, as represented by the expression, - log -a = X con- t ar-x stant, where a = the tin in the stannic bromide, x = the tin in the precipitated metastannic acid, H1Sn04,and t = the time in minutes. 'rhe value of R found = 0.000726-0.000906, t = 1430-3890, In one case K = 0.001071, t = 1010, the difference between this value and those given above is probably due to incomplete precipitation o€ the metastannic acid. J. B. T.

Cerite Earths. By PAULSCHUTZEKBERGER (Compt. rend., 1895,120, 1143--1147).--The niebhods previously employed (this vol., ii, 352) have been extended to the nitrates remaining nndecomposed in View Article Online

INORGANIC CHEMISTRY. 449

presence of excess of potassium nitrate after complete elimination of the cerium. These nitrates were fractionated by heating them at gradually increasing ternpei*atures, and t,he treatment was repeated on some of the first products of the fractionation. The general result is that the curve of the atomic weights of the metals contained in the successive fractions rises from a minimum of about 135 to a maxi- mum of 143 to 143.5, and then descends to a second minimum of about 138. The maximum atomic weight of didymium lies betweeii 143 and 143.5. When monazite is subjected to the same treatment as cerite, the oxides which separate from the fused nitrates between 410’ and 460°, after careful elimination of the cerium, form decidedly rose-coloured salts, which show the absorption bands of neodymium, and contain a metal with an atomic weight very near 137.5. There are reasons for believing that between the two limits of 143.5 and 137.5 there are other metals which have all the general properties of didymium, and in particular an element with an atomic weight of about 140. Lanthanum oxide (as defined subsequently) can be split up into at least two oxides, the one containing a metal with an atomic weight of abo-ilt 138, and the other a metal of atomic weight of about 135. As in the case of didymium, the stability of the nitrates when heated is higher the lower the atomic weight of the metal. The mithor defines as cerite earths all the oxides which give a double potassium sulphate insoluble in a saturated solution of potassium sulphate ; as cel-ite oxides all the oxides capable of conversion into a dioxide, and forming colourless salts, the solutions of which show no- absorption bands ; as didynjizcm oxides all those which form more or less rose-coloured salts, the solutions of which show the absorption bands of didymium salts, the oxide formed at high temperatures being M203;and as Zunthalzum oxides those which form colourless deli-

Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. quescent salts, with no absorption bands, and yield an oxide, &Oa, when strongly heated. (Compa-re Schutzenberger, Zoc. cit., and Brauner, ibid.) C. H. B. Iodine Compounds of Lead with Excess of Iodine. By HORACEL. WELLS (Zeit. artorg. Chem., 1895, 9, 304-311, and -her. J. Sci., 50, 21--26).-The salt, 5Pb(OA4c),,3KJ,6I,which has been prepared by Johnson (Trans., 1878,189)by mixing a hot, concentrated, alcoholic solution of potassium triiodide with a hot, saturated solutioii of lead acetate, has been examined by the author. It is formed when 30 grams of potassium iodide and 50 grams of iodine dissolved in absolute alcohol are mixed with $0-100 grams of crystallised lead acetate also dissolved in alcohol, separating in crusts or groups of larger crystals, which are fairly stable when exposed to the air. The lead and potassium are determined in the salt by dissolving it in ciilute nitric acid, precipitating the lead as sulphate, and estimating the potassium in the filtrate also as sulphate ; the iodine is determined by treating the salt with a solution of sodium arsenite, acidifying with nitric acid, and then adding excess of silver nitrate. The salt, Pb215(OH),,previously described by Groger, but to which he assigned the formula Pb2150,has ah0 been examined. It is View Article Online

450 ABSTRAOTS OF OEEMIOAL PAPERS. most easiiy obtained by mixing a solution of 10 grams of iodine in LOO C.C. of absolute alcohol, with a solution of 50 grams of crystdlised lead acetate in 150 C.C. of water, 3 C.C. of acetic acid, and 300 C.C. of absolute alcohol ; after 14-16 hours, it is filtered from a slight, precipitate and diluted with 1.5 litrev of boiling water. On cooling, the salt crystallises out in lustrous, black octahedra, which are fairly stable when exposed to the air ; it is not decomposed by cold water, or by alcohol. Using GrGger's method, the salt is obtained as a reddish-brown powder, but it has the same composition as t,he crp talline salt. E. C. R. Reactions of Lead Sulphide. Br ARTHURLODIN (Compt. rend,, 1895, 120, 1164--1167).-Lead sulphate, alone, or mixed with other substances, was heated in a glass or porcelain tube, the temperatures being measured by means of a Le Chatelier thernioelectric couple, When heated at 860" in a current of carbonic anhydride, lead sulphide volatilises to a considerable extent, and at the same time is partially oxidised ; in a current of nitrogen, it volatilises completely at 860", without previously melting. The melting point of the sulphide when rapidly heated is between 930' and 940'. Mixtures of the sulphide with the monoxide, or the snlphate, when heated in porcelain tubes in an atmosphere of nitrogen, gave results which confirm the accuracy of the ordinaryequations, PbS + 2Pb0 = 3Pb + SO,; PbS + PbS04 = 2Pb + 2S0,; and PbS + 3PbSO4 = 4Pb0 + 4S0,. Although lead sulphide only melts at 935', it has a very consider- able vapour tension even at much lower temperatures, and this fact explains not only the phenomena of volatilisa tion, which Hannay attributed to the formation of a hypothetical compound, PbS,02 (Proc., 1894, 113 and 151), but also the interactions between the sul- phide on the one hand, and the oxide or snlphate on the other, at tern-

Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. peratures below 935'. C. H. B. Action of Nitric Peroxide on Antimony Salts. By VIKCENT THOMAS(Con~pt. rend., 1895, 120, 1115--1117).-l'he action of nitric peroxide on a solution of antimony trichloride in chloroform yields a white, somewhat stable, compound of the composition Sb4OI1N2Cl4,probably 2Sb02, 2SbOC1,,N205,or (O*SbO), 2N02<( O*SbOCI,),' Antimony tribromide, under the same conditions, yields the white compound, Sb4OIoN4or N205,2Sb,05, analogous to the compound 2Sb2O3,N2O5,obtained by Peligot by the combination of nitric and a,ntimonious anhydrides. C. H. B. Salts of Amidochromic acid. By ALFREDWERNER and A. KLEIK (Zeit. anorg. Chem., 1895, 9, 291--'L94).-The authors have endea- voured to prepare potassium amidochromate, KCrO3NH?, and the compound, Cr20,H2N, described by Heintze (J.pr. Chern., 4, 216), rn obtained by the action of dry ammonia on potassium chlorochromate. The authors, however, following strictly the conditions laid down by View Article Online

INORGANIC CHEMISTRY. 45 1 Heintze, obtained nothing but potassium dichromate, and they were not more successful when they modified his method. E. C. R. Conductivity of Permanganic acid. By JOH.M. IIOV~N(Zed. physilml Chem., 1895, 17, 374--376).--Owing to the piiblication of work by Franke on the conductivity of perroanganic acid, the author claims priority of determination and publication. The values for the conductivity given increase from 315 at V = 2 to 378 at V = 256, after which it remains constant ; the value at infinite dilution given by Fritnke was 383-8. The numbers are in general higher than those of Franke, this being attributed to the precautions taken by the author to prevent the decomposition ol the acid by the platinum black. L. M. J. Nitroso-compounds of Iron. By KARLA. HOFNANNand 0. F. WTEDE(Zeit. ano3.g. Chem., 1893, 9, 295--303) .-The authors have already described salts of dinitrosoferrothiosulphonic acid (this vol., ii, 317), and the method by which they can be prepared; other salts have now been obtained. The rubidium salt, Fe(N0)&03Rb + H20, obtained by adding rubidium chloride to a solution of the sodium salt, crystallises in lusti-ous, black needles, and is less soluble than the sodium salt. The ccmiurn salt crystallises without water in lustrous, black crystals, and is sparingly soluble. The authors were unable to obtain a thallium salt corresponding with the preceding; this non-forma- tion of a thallium salt affords a characteristic distinction bettween dinitrosoferrothiosulphonic acid and heptatiitrosoferrothiosulphonic wid, the latter yielding a very characteristic thallium salt of the com- position Fe4(N0)7S3TI. The thio-group in dinitrosofem-othiosulphonic acid is very easily eliminated, and, when a solution of the sodium Ralt is boiled as long gas

Published on 01 January 1895. Downloaded 25/10/2014 07:12:09. as is evolved, the sodium salt OE the hepta-acid is formed; this crystallises in needles, and may be characterised by converting it into the thallium salt. Ccesium hel3tanitrosoferrothiosulphonic acid, Fed( N0),S3Cs,H20,obtained by adding caesium chloride to a solution of the sodium salt, separates as a black, Crystalline powder, and is very sparingly soluble. The rubidium salt with lH20is obtained as a black, crystalline powder. The n.mmoniurn salt, Fel(N0)7S3(NHb),H30,is obtained by passing nitrous oxide into freshly precipitated ferrous sulphide suspended in water, or into a mixture of ferrous hydroxide, ferrous sulphate, and carbon bisulphide saturated with ammonia, and also by passing the gas into a mixture of ferrous hydroxide and carbon bisulphide. The salt, extracted from the product of the action by hot alcohol, crystallises in lustrous, black needles ; when distiIled with soda, it jields more than the theoretical quantity of ammonia, because some of the nitrous oxide is also converted into ammonia. Hepta- nitrosoferrothiosulphonic acid is easily detected by converting it into the Characteristic csesiuni salt. The compound, Fe(NO),SEt, is obtained by treating a mixture of ferrous sulphate, potassium hydroxide, water, and ethylic mercaptart with nitrous oxide ; it crystallises from absolute alcohol in larg0, View Article Online

452 ABSTRAOTS OF OHEMICAL PAPERS. lustrous, black, six-sided plates, has no odour, melts at 78" to a brownish-black liquid, is volttt