Inorganic Chemistry. 697

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INORGANIC CHEMISTRY. 697

Inorganic Chemistry.

Physical Properties of Liquid and Solid Hydrogen. Separa- tion of Free Hydrogen and other Gases from Air. Experi- ments on the Liquefaction of Helium at the Melting Point of Hydrogen. Pyroelectricity, Phosphorescence, &c. By JAMESDEWAR (PYOC. Roy. XOC.,1901, 68, 360-366).-A helium thermometer has given 205O absolute as the boiling point, and 16' absolute as the melting point, of hydrogen (compare Trans., 1898, 73, 534; Abstr., 1899, ii, 741 ; this vol., ii, 308). The lowest temperature recorded in gas thermometry is 14.5' absolute, but with solid hydrogen, with more complete isolation and lower pressure of exhaustion, it will be possible to reach 13O. The latent heat of liquid hydrogen at its boiling point, as deduced from the vapour pressures and helium-thermometer temperatures, is about 200 units, and the latent heat of solid hydrogen is not greater than 16 units. From (1) the percentage of liquid hydrogen which has to be quickly evaporated in order to reduce the temperature to the freezing point, and (2) the latent heat of evaporation, the average specific heat of liquid hydrogen between freezing and boiling points has been found to be about 6. It thus appears that hydrogen obeys Dulong and Petit's law, and has a greater specific heat than any other known substance. The surface tension of hydrogen at its boiling point is about one- fifth that of liquid air under similar conditions, and about 1/35 that of water at the ordinary temperature.

Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. Experiment gives 1.12 as the refractive index of liquid hydrogen, whilst the calculated value is 1.11. Thus the refractivity of hydrogen, like that of liquid oxygen and nitrogen, is in accordance with theory. Hydrogen, helium, and neon have been separated from air by two methods. By one of these, a crude, uncondensed residue was obtained amounting to 1/34000 of the volume of air liquefied ; this residue con- tained 32.5 per cent. of hydrogen, 8 per cent. of nitrogen, and 60 per ceut. of helium, neon, &c. After removal of the hydrogen and nitrogen, the neon can be solidified by cooling in liquid hydrogen. When a current of air is passed through a spiral filled with glass wool and immersed in a liquid air-bath, the condensed gas consists mostly of xenon : if the bath is kept at a slightly lower temperature by exhaustion, and the pressure of the air current suitably reduced to prevent liquefaction, krypton is deposited along with the xenon. Comparative experiments made with hydrogen and helium in a Cailletet apparatus seem to indicate that the critical temperature of helium is under 9O absolute. It is certain that helium has been cooled to that temperature without any appearance of liquefaction. But the author points out that the refractive index of liquid helium at about its boiling point will be about 1-03,and that, therefore, small drops of liquid helium forming in the gas near its critical point will not easily be View Article Online

598 ABSTRACTS OF CHEMICAL PAPERS.

seen. In order to liquefy helium, the process which was successful in the case of hydrogen will have to be applied, only liquid hydrogen under exhaustion will have to be used as the primary cooling agent instead of liquid air. Experience of the cooling effect produced by the regenerating process shows that the use even of liquid helium, with a probable boiling point of 5' absolute, would not enable us to reach the absolute zero. To reach the temperature of lo, another gas would have to be found as much more volatile than helium as the latter is than hydrogen. The phosphorescence effects observed when organic substances are cooled by the use of liquid air are much more marked when liquid hydrogen is employed. When zinc sulphide is cooled to 21' absolute and exposed to light, it shows brilliant phosphorescence on the temperature rising. The intensity of photographic action is halved by lowering the temperature from that of liquid air to that of liquid hydrogen. Remarkable electrical and luminous effects are developed by placing certain crystals (especially of some platinocyanides and of uranium nitrate) in liquid hydrogen. J. C. P. Separation of the least Volatile Gases of Atmospheric Air, and their Spectra. By G. D. LIVEINGand JAMESDEWAR (Proc. Roy. h'oc., 1901, 68,389-398. Compare this vol., ii, 213)-When the less volatile portions of liquid air are allowed to evaporate gradu- ally at a slowly rising temperature, and the gas given off is spectro- scopically examined from time to time, the spectra of argon, krypton, and xenon are observed in the order given. Full details are given in the paper of the apparatus used in the distillation and separation of xenon and krypton, and the wave-lengths of their rays are tabulated in full. Most prominent in the xenon spectrum are four orange rays, a group of very bright green rays, and several very bright blue rays. The krypton lines given coincide closely with those in Runge's list, but Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. are more numerous than the latter. J. C. P. Occurrence of Nitrogen and Helium in Uranium Minerals. By VOLKMARKOHLSCH~TTER (AhnuZen, 1901,317, 158-189. Com- pare Tilden, Abstr., 1898, ii, 383; Gautier, this vol., ii, 171, 398).- This communication contains a summary of the work of earlier in- vestigators and an account of experiments made with the view of determining the state in which nitrogen and helium exist in minerals. In preparing finely divided uranium, it was found that its two lower oxides behave very differently towards reducing agents ; the dioxide, UO,, is not reduced when heated with magnesium or aluminium powder, whilst the green oxide, U,O,, reacts very violently with these reagents, the reduction being conveniently moderated by the addition of a certain amount of the lower oxide. When aluminium is employed, it is advisable to use a priming of magnesium or of barium or sodium peroxide. The nitride, U3N4,produced when this reduction is conducted in an atmosphere of nitrogen, is exceptionally stable at high temperatures and is not attacked by solutions of the alkali hydroxides or by concentrated sulphuric or hydrochloric acid ; fusion with potash results in the elimination of the nitrogen in the form of ammonia. The gaseous View Article Online

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constituent is evolved in the free state on heating the nitride with oxidising agents, this result being also produced in the presence of steam, ferric oxide, copper oxide, and the oxide U,O,. The compound remains unchanged when heated in a current of nitrogen, but in contact with hydrogen at high temperatures a small amount of ammonia is produced; when burnt in oxygen, the nitride leaves a residue of pure U,O,. This nitride is black, whereas the product obtained by heating uranium in an atmosphere of nitrogen at 1000° is stated by Moissan to be yellow. The yield of yellow thorium nitride, Th,N,, obtained by substituting thorium dioxide for the uranium compound in the preceding reduction is comparatively small ; under these conditions of experiment, a considerable amount of dioxide remains unreduced, and since it passes into solution on treating the fused mass with water, it probably exists in the product in the form of a magnesium thorate. This nitride differs markedly from the isomeride prepared by Matignon (this vol., ii, 60 and 106); it is not decomposed by water or dilute acids, and when heated to dull redness in air or oxygen it burns with a luminous flame. The name metanitvide is suggested for the new compounds obtained from the metals while in the nascent state ;these products are probably identical with the corresponding nitrides existing in the uranium minerals. Nitrogen is evolved on heating these minerals because of the oxidising action of the oxides (Fe,O,, U,O,, &c.), which are always present, Certain experimental results seem to indicate that helium exists in these minerals in a similar state of combination, its compounds, like the above nitrides, being decomposed by the action of the oxides at high temperatures. For example, the helium in samarskite is completely eliminated when the mineral is heated in carbon dioxide, but

Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. only a portion of the gas is evolved when the experiment is conducted in an atmosphere of hydrogen. This difference is readily explained on the assumption that the oxidising agents are reduced by the hydrogen before they can react with the helium compounds. On the other hand, it was not found possible to synthesise a helium compound by heating the gas in contact with uranium oxide or previously ignited samarskite mixed with aluminium powder, although nitrides are readily produced under these conditions in an atmosphere of nitrogen. G. T. M. Compounds of Telluric Acid with Iodates, Phosphates,and Arsenates. By RUDOLPHF. WEINLANDand Huao PRAUSE(Zeit. anorg. Chem., 1901, 28, 45-70. Compare Abstr., 1900, ii, 399).-A short review is given of the compounds which iodates, phosphates, and arsenates form with acids containing an element of the sixth group (S,Cr,Mo, W). In addition to the telluriodates previously described, an ammonium tellurimonoiodat e, (NH,),O, T20,, 2Te0,, 6H,O, analogous to the potassium and rubidium salts, has been produced by crystallising at the ordinary temperature, It is only at lower temperatures that the salt with 8H20 is formed. View Article Online

600 ABSTRACTS OF CHEMICAL PAPERS.

The telluriphosphates are likewise obtained by crystallisation from concentrated solutions of the components. Of these, the following are described : potassium telluridiphosphate, 1~5K,0,P,05,Te0,,17*5H,0, crystallises from the solution below 40'; in a vacuum, it loses nearly 3/4 of its water and becomes 1*5K,0,P,0,,Te0,,4~5H20, The rubidium salt is analogous to the second potassium compound. Sodium tellurimonophosphate, 2Na20,P,05,2TeO~,9H20,is best obtained from a solution containing phosphoric acid, telluric acid, and sodium hydroxide in the proportion 2 : 1 : 2. Ammonium tellurimonophosphate, 2(NH4),0,P,0,,Te03,4H,0, and ammonium telluritriphosphate, 4(NH4)20,3P20,12Te03,1lH,O,. are obtained from solutions containing the components in the proportions indicated by the formulae. Sodium tellurimonoarsenate, 2 Na20,As,05,2Te0,,9H,0, ammonium telluridiarsenate, 2(NH4),O,As2O,,Te0,,4H,O, and ammonium telluri- triarsenate, 4(NH,),0,3As20,,2Te0,,1 1H,O, corresponding with the phosphates, have been prepared, but no potassium or rubidium salts could be obtained. The crystallographic relationships of all the compounds have been measured. The authors discuss the constitution of the various compounds in the light of Blomstrand's theory OF the constitution of the molybdo- iodates (Abstr., 1890, 107). J. McC. Decomposition of Sodium Nitrate by Sulphuric Acid. 11. By C. W. VOLNEY(J. Amer. Chem. Xoc,, 1901,23,489-492. Compare Abstr., 1892, 941).-When a mixture of sulphuric acid and sodium nitrate is heated at a temperature below 100' until no more nitric acid distils over, the residue in the retort consists of unchanged sodium nitrate and an oil, which, on cooling, crystallises. The crystals have approximately the composition NaH3(S04),. If the mixture is heated

Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. at a temperature of 121' until no more acid distils over, the residue consists only of sodium hydrogen sulphate. In the first period of the reaction, pure nitric acid is obtained ;in the second period, a somewhat diluted acid is produced. K. J. P. 0. Cesium Compounds. By CAMILLECHABRIB (Compt. red., 1901, 133, 295-297. Compare this vol., ii, 314).-In order to completely decompose pollux, it is advisable to dry the very finely divided mineral at 130°, and then add it to about 100 times its weight of pure hydro- fluoric acid. The following salts are described. Cesium hydrogen sulphite, CsHSO,, obtained as a white 'precipitate on saturating an alcoholic solution of the carbonate with sulphur dioxide ; cEsiurn sulphite, Cs,SO,, snow-white crystals ; ccesium thiosulphate, Cs,S,O,, colourless needles ; cczsiulm dithionate, Cs2S20s,obtained from cmsium sulphate and barium dithiona te, large hexagonal plates. All these compounds are readily soluble in water. J. J. S. [Non-existence of Ammonium at - 95'1. By OTTORUFF (Chem. C'entr., 1901, ii, 391 ; from Ber. hut.pharm. Get?., 11, 277-2S8).- A saturated solution of ammonium iodide in liquid ammonia, cooled to - 95O by means of liquid air, was subjected to electrolysis. At the positive pole, nitrogen iodide separated, but at the negative pole only View Article Online

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hydrogen was evolved, being obviously derived from the decomposition of ammonium into ammonia and hydrogen. E. W. W. Reaction between Chlorine and Ammonia. By WILLIAM A. NOPESand ALBERTC. LYON(J. Amer. Chem. Soc., 1901, 23, 460-463).-It is shown that the normal reaction between ammonia and chlorine is represented by the equation : 1ZNH, + 6Cl, = N, + NCI,+ 9NH4CI, the volume of nitrogen being one-sixth that of the chlorine. If the ammonia is present in excess, it reacts with the nitrogen chloride, giving free nitrogen and probably also ammonium hypochlorite, thus : NCl, + NH, = N, + 3NH4CL and NCI, + NH,O€€ + H,O = 3NH4C10. If the chlorine is present in excess, the ammonium chloride which is formed reacts with it to some extent, and little or no nitrogen is evolved. The nitrogen chloride was estimated by extracting the product of the reaction with benzene. The benzene solution was shaken with excess of arsenious oxide dissolved in a solution of sodium hydrogen carbonate, and the excess of the oxide determined by standard iodine. After titration, the ammonia was estimated by distillation. I(. J. P. 0. Action of Silver on Hydrogen Bromide and the Inverse Reaction. By JOUNIAUX(Compt. rend., 1901, 133, 228-231)- When silver is heated with hydrogen bromide in sealed tubes, the action is at first rapid, but after a time equilibrium is reached, and is maintained at any given temperature, even if the heating is much prolonged. The action of hydrogen on silver bromide is analogous, and the limiting pressures at a given temperature are identical in the two cases. If hydrogen is introduced at different pressures into the tube containing the silver bromide, the proportion of hydrogen bromide formed when equilibrium is attained at n given temperature, is higher the lower the initial pressure. The results are in accord with the law

Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. of the displacement of equilibrium by variations of temperature, and the observed and calculated results agree closely. C. H. B. Action of Cupric Hydroxide on Solutions of Metallic Salts. By A. MAILHE(Compt. rend., 1901, 133, 226--228).--The cupric hydroxide, Cu,O,(OH),, acts on solutions of several metallic bromides and chlorides at the ordinary temperature, yielding crystalline basic double bromides or chlorides. Iu this way, the following compounds were obtained : Zi1C12,3Cu0,4H,0, small, blue plates or hexagons; ZnBr,, 3CuO, 4H,O, green ,stellate crystals; MnCl,, 2 CuO,6H,O, a green powder consisting of minute hexagons ; COC~~,~CUO,~H,O,a green, crystalline powder (hexagons) ; NiC1,,ZCuO,6H2O, a pale green, crystalline powder ; NiBr,, ZCuO,ZH,O, in green, quadrangular lamellae, and CdC12,2Cu0,6H,0, a grey, crystalline powder. The black oxide and the blue hydroxide as a rule yield the same products, but if the liquid is heated, the basic compounds may contain less wat,er of crystallisation. The blue hydroxide, with nickel chloride in the cold, yields the compound NiC12,3Cu0,4H20. Mercuric chloride and bromide are not affected by cupric oxide or hydroxide in the cold, but if boiled with the blue hydroxide, mercuric chloride yields a green, amorphous compound, HgC1,,3Cu0,H20. C. H. B. View Article Online

602 ABSTRACTS OF CHEMICAL PAPERS.

Preparation of pure Cerium Oxide. By JEANSTERBA (Compt. rend., 1901, 133, 221--223).-The method of Wyrouboff and Verneuil (Abstr., 1897, ii, 452) can be made more rapid by oxidising the cerous nitrate to ceric nitrate by means of a current of about 0.7 ampere and 2 volts, the liquid containing about 1 per cent. of nitric acid. The ceric oxide is precipitated with ammonia and a small quantity of ammonium sulphate, and the precipitate washed with water containing 5 per cent. of ammonium nitrate and 1 per cent. of ammonium sulphate. The process is repeated until the substance shows no absorp- tion spectrum. Cerium oxide, free from other metals, will show a reddish coloration if it contains small quantities of nitrogen. It is slightly reduced by hydrogen at a high temperature, and is also reduced when heated with zinc, but not when heated with cadmium. C. H. B. Crystallised Cerium Oxide. By JEANSTERBA (Compt. ?*end., 1901, 133, 294-295).-When fused with sodium chloride, borax, or potassium sulphate, cerium oxide forms colourless, transparent cubes, or combinations of cubes and octahedra of sp. gr. varying from 7.314 to 7,995. J. J. S. Neodymium Chloride. By CAMILLEMATIGNON (Compt. rend., 1901, 133, 289-291. Compare Abstr., 1900, ii, 142).--Neodymizcm chloride, NdCI3,6H,O, crystallises in large, deliquescent, rose coloured, monoclinic forms. It has a sp. gr. 2.282 at 16.5"/4', and the molecular volume 156.9. Its solubility in 100 parts of water is 246.2 parts at 13O and 511.6 at 100'. An aqueous solution saturated at 13' has the sp. gr. 1.741 at 15'14'. Its heat of solution is +7.60 Cal. When dried in a current of dry hydrogen chloride, it yields the hydrate NdCl,,H,O, which on further heating above 160° forms the anhydrous chloride, the heat of solution of which is +34.8 Cal. The anhydrous chloride dissolves readily in absolute alcohol, and ebullio- Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. scopic and cryoscopic determinations with the solution point to the simple molecular formula NdCl, for the substance. J. J. S. Supposed Alteration of the Properties of Aluminium. By PIETROSPICA (Gaxxettcc, 1901, 31, ii, 67-72; Boll. Chim. Fama., 40, 341-345. Compare Le Bon, this vol., ii, 20).-The formation of streaks of alumina when aluminium is shaken with mercury does not take place as a rule in less than two minutes, and when the oxide is removed and the process repeated, the streaks can be obtained only once, or at most twice, more. Water is decomposed only very slowly by aluminium in presence of mercury, and after a time no further decomposition occurs. When strips of aluminium are immersed in water containing a few drops of hydrochloric acid and a very small quantity of mercuric chloride, the formation of alumina may be observed in a few minutes ; the strips, when removed from the liquid, oxidise very quickly in the air and decompose water, but after repeat- ing the treatment two or three times they lose both these properties. E. w. w. Alloys of Aluminium and Molybdenum. By LBON GUILLET (Compt. rend., 1901, 133, 291-293. Compare this vol., ii, 512).- The dross from the crystalline alloys previously described (Zoc. cit.), View Article Online

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after treatment with very dilute hydrochloric acid, has yielded further crystalline products. The definite alloys so far isolated are, Al,Mo, Al,Mo, Al,Mo, AlMo, AlMo,, and probably AlMo,,,. The state of divi- sion of the aluminium employed in reducing the molybdic acid exercises considerable influence on the composition of the alloys obtained. J. J. S. Physical and Chemical Changes in Solutions of Ferric Salts. By EDUARDSCHAER (Arch.:Phrrn., 1901,239,257-283 and 340-353). -The author describes the effect of dilution and of heat on the colour of solutions of ferric chloride, sulphate, nitrate, and acetate, and com- pares the colours of aqueous and alcoholic solutions of the same salts at ordinary and higher temperatures. The intensity of reaction of ferric salts with ferrocyanide, thiocyanate, salicylic acid, &c., is diminished by rise of temperature, but increased generally in the presence of alcohol, As pointed out by Schonbein, sulphurous acid intensifies the colour of ferric salt solutions, and the latter thereby acquire an increased power of oxidising and decolorising indigo ; these observations have been confirmed and extended by the author. The varied phenomena recorded are arranged at length in tabular form. They are to be explained by two factors: (1) A hydrolytic dissociation of the ferric salt into acid and oxide, (2) an increased reactivity of the oxygen of the ferric oxide from the iron salt. J. C. P. Uranyl Nitrate. By F. JANDA(Chem. Cent?', 1901, ii, 266; from Oesterr. Zeit. Berg-Hutt., 49, 325-328, and 340--342).-Uranyl nitrate, U02(NOB),,6H20,is prepared on the large scale by dissolving uranium pentoxide in nitric acid of sp. gr. 1.321. The pentoside is obtained by igniting ammonium uranate in graphite crucibles. The original paper contains an account of the various phases of the process, the composition of the crude materials, the technical application of the salt, and a &sum5 of previous work.

Published on 01 January 1901. Downloaded 23/10/2014 07:23:28. E. W. W. Studies on Solutions of Stannous Salts. 111. By STEWARTW. YOUNG(J. Amer. Chem. Soc., 1901, 23, 450-460. Compare this vol., ii, 318, 390).-Course of the reaction between stannous chloyide and oxygen. The conductivity of solutions of stannous chloride (0.16N) to which varying amounts of hydrochloric acid had been added was determined at 20' after oxidation. The conductivity of such solutions increases slowly, and only after some hours reaches a constant value. This increase, which is very rapid at first, is greater for solutions more concentrated with respect to hydrochloric acid than for those less concentrated. The results obtained when free oxygen, potassium di- chromate, ferric chloride, hydrogen peroxide, or sodium hypochlorite was used for the oxidation were all similar. The facts that it requires some considerable time for the equilibrium to be attained, and that the increase in the conductivity is dependent on the concentration of the hydrochloric acid, lead the author to conclude that the first stage in the oxidation of stannous chloride is the formation of stannic chloride for which hydrochloric acid is necessary, and the second stage is the hydrolysis of t'he stannic chloride. Kinetics of the reaction between stannous chloride and oxygen. The author discusses the reaction from the point of view that the hydro- View Article Online

604 ABSTRACTS OF CHEMICAL PAPERS.

chloric acid takes part in the reaction in the first stage and is a product of the secondary reaction. It is shown that in certain cases the value of dx/dZ” may reach a maximum in reactions such as this, and Ostwald’s statement that such maxima can only occur when catalytic influences are at work is too broad. J. McC. Metathorium. By GRBGOIREN. WYROUBOFF(Zed. anorg. Chem., 1901,28, 90-91).-Stevens (this vol., ii, 391) has taken no account of the work of Wyrouboff and Verneuil (BUZZ.Soc. Chim., 1899, [iii], 21, 118; also Abstr., 1899, ii, 224) on the polymeric thoric oxides. It was there shown that many oxides possess the power of polymeris- ing, and the product acts as a bivalent radicle. The compounds with acids belong to the group of “complex ” compounds. Metathorium oxide [the author regards thorium as bivalent and writes this (Tho),] combines with acids without elimination of water, thus with hydrochloric acid (ThO),SHCl is formed. On several points, Stevens’ work is not in agreement with the author’s. J. McC. Atomic Weight of Antimony. By G. CLAUSENFRIEND and EDGAR F. SMITH(J. Amer. Chern. Xoc., 1901, 23, 502--505).-Pure potassium antimony1 tartrate was heated in a stream of hydrogen chloride and the potassium chloride thus formed freed from carbon by ignition in a current of oxygen. The residue was then extracted with water, and the solution of potassium chloride evaporated in a platinum dish, Eight determinations of the atomic weight were made, and the mean value obtained was 120.353 (0=16), the maximum and minimum values differing by 0.074. K. J. P. 0. Published on 01 January 1901. Downloaded 23/10/2014 07:23:28.