Inorganic C Hernist Ry

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INORC ANIC CHEMISTRY. ii. 107

Inorganic C hernist ry.

The Hydrides of the Metalloids. R. DE FORCRAND(J.Chim.

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. phys., 1917, 15, 517-540).-An elaboration of work already published (compare A., 1905, ii, 696) and a discussion of Berthoud’s work on this subject (compare A., 1917, ii, 237). W. G. Hydrogen Peroxide as a Reducing Agent. M. KLEIKSTUCK (Rer., 1918, 51, lO&-lll).-SiIver chloride, suspended in potassium hydroxide solution, is quickly reduced by hydrogen peroxide according to the equation 2AgC1+ H,O, + 2KOH = 2Ag + 0, + 2KCI + H,O. Carbonyl chloride and phenyl carbonate also react with alkaline hydrogen peroxide, and so does a saturated solution of potassium hydrogen carbonate if kept at looo in a pressure bottle. The dis- tillate obtained by passing steam through the products reduces ammoniacal silver oxide, and is therefore said to contain form- aldehyde. The author sees in these reactions a new interpretation of the assimilation of carbon dioxide by plants, thus : H,CO, + H,O, -- CB,O + H,O + 30. [See also T)2TJ., April.] J. C. W. Variations of the Density of Air and the Loomis-Morley Law. PH.A. GUYE(J. Chim. phys., l917,15,561--566).--A study of the results obtained by various workers for the weight of a normal litre of air, in which it is shown that the results, taken its View Article Online

ii. 108 ABSTRACTS OF CHEMICAL PAPERS.

a whole, verify the qualitative experimental relation, stated by Loomis and Morley, between the density of the air and the baro- metric pressure. The most probable explanation of such variations in density is based on the presence in the air of varying quantities of dust, invisible under the ultramicroscope. The mean of the most modern determinations gives the value 1.2928 grams as the weight of a normal litre of air. w. G. Portable Hydrogen Sulphide Generator. W. F,PITOUTE MUNN(J. Id. Eng. Chem., 1918, 10, 130--131).-A wide glass tube has two bulbs formed at its lower end, the bottom bulb being provided with a draw-off tap. A perforated lead plate is fitted at the constriction between the bulbs (a piece of glass tubing in the lower bulb acts as a support for the plate) and ferrous sulphide is filled into the UP er bulb. The acid reservoir consists of a large bulb, the stem o f which passes through a cork closing the top of the wide glass tube and extends to the bottom of the lower bulb. A tapped exit tube for the gas is placed near the top of the wide] tube, and this exit tube is fitted with a small washing tube. w. P. s. Automatic Hydrogen Sulphide Stopcock. CARLH. CLASSEN (J. Ind. Etzg. Chem., 1918, 10, 131--132).-To the delivery tube of the hydrogen sulphide apparatus is attached a length of rubber tubing in which is inserted a glass '' pearl " made from glass tubing having a diameter slightly larger than that of the rubber tubing. When the rubber tubing over the " pearl" is compressed between the finger and thumb, a channel for the flow of the gas is formed between the glass and the rubber. w. P. s. Chlor o- and B rorn o-aminosulphonic Acids. W ILH ELM

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. TRAUBEand E. VON DRATHEN(Ber., 1918, 51, lll--115).-Solu- tions of potassium aminosulphonate and hypochlorous acid in equi- valent proportions react in the cold to form potassium chloroamino- stclphonate, NHCl*SO,K, which may bel isolated by evaporating the mixture to a small bulk, in a high vacuuni, at as low a temperature as possible and precipitating with alcohol. The salt forms limpid, hygroscopic crystals, and is comparatively stable. When warmed with mineral acids, hydrolysis takes place according to the equation NHCl*SO,H + H,O = NH,CZ + H,SO,. The corresponding barium salt is not so stable, but potnssiicm bromoamino- sulphoncxte is very similar. Similar salts may be prepared by the interaction of free aminosulphonic acid and metallic hypochlorites. Alkylaminosulphonates apparently give very unstable products, for evolution of gas is noticed as soon as hypochlorous acid is added. There are indications that a double amount of hypochlorous acid produces less stable dichloroaminosulphunates. J. C. W. Rate of Hydrolysis and Electrical Conductivity of Hypo- phosphoric Acid Solutions. R. G. VANNAVE and WILRERTJ' HVFF('4 mer. ,7. Sci., 1918, [iv], 45, 103--118).--The idometric View Article Online

INORGANIC CHEMISTRY. ii. 109

method for the estimation of phosphorous acid in presence of hypophosphoric acid (this vol., ii, 128) has enabled the authors to in- vestigate the rate of hydrolysis of the latter acid. The data obt,ained at' 25O and 600 show that' in dilute solutdons containing hydrochloric acid as catalyst the hydrolysis proceeds in accordance with the equation for a unimolecular change. The velocity coefficient increases much more rapidly than the hydrogen ion con- centration. The temperature coefficient for loo is 2.7. The fact that the hydrolysis follows a unimolecular law is in favour of the formula H4P90, rather than H,PO, for hypophosphoric acid, for the production of phosphorous and phosphoric acids would require the interaction of two molecules of acid if it had the simpler formula. For the conductivity measurements, pure solutions of the acid were prepared from lead and copper hypophosphate by the action of hydrogen sulphide at low temperatures. The metallic sulphides were filtered off and the excess of hydrogen sulphide removed by a current of air. The conductivity of the solutions after complete hydrolysis was also determined. The molecular conductivity at 25O referred to the formula H4P,0, increases from A = 384.7 at' E = 32 to A = 629-3 at 'u = 1024. After hydrolysis, the conductdvity of the stronger solutions is diminished, whilst that of the more dilute solutions is increased. Attention is directed to the resemblqnce between thel properties of hypophosphoric acid and pyrophosphoric acid. This resemblance is found in the conductivity of the solutions, in the behaviour towards indicators, and in their solubility relations, and may be adduced in support' of the formula H,P,O, for hypophosphoric acid. R.M. D. Preparation Amorphous Boron, WILHELMKROLL (Zeitsch.

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. of nnorg. Chem., 1918, 102, 1-33).-The paper gives t8heresults of numerous experiments on the reduction of boron compounds. Aluminium is unsuitable. Sodium yields mixtures of the lower oxides of boron mixed with boride. Calcium produces only borides. Magnesium may be used for the reduction of boric acid, but the product contains more than 3% Mg in the form of insoluble boride. The halogen compounds of boron can be reduced by potassium, sodium, magnesium, and aluminium; in each case, borides of the metal are formed as well as free boron. The purest boron is obtained by the reduction of boron chloride with hydrogen in the high tension electric arc. Red phosphorus does not reduce boric acid. When boric acid is heated with magnesium nitride, a boron n,itride, probably B,N, is produced. Boron nitride, BN, can be conveniently prepared from boric acid and calcium cyanamide. When boron chloride is passed over red phosphorus in the presence of oxygen, a yhocphntP, 5?B,O,P,O,, is formed. Other phosphates appear to exist. The original contains details as to analytical processes regarding compounds of boron. [See, further, Izd., 1484.1 R. V. S. View Article Online

ii. 110 ABSTRACTS OF CHEMICAL PAPERS. Nomenclature of Silicon Compounds. ALFREDSrocK (h’er., 1917, 50, 1769-1771. Compare A., 1917, ii, 204).-The author again emphasises the fact that very little chemical similarity exists between silicon and carbon compounds of the same structure, and proposes to abandon the nomenclature of carbon chemistry as far as possible. For example, the radicle -SiO*OH in no way resembles a carboxyl group, and therefore the term “hydroxyoxo” is sug- gested in such a case. J. C. TY. Silicon Hydrides. 11. Bromination of Monosilane, SiH4. SiH,Br and SiH,Br,. ALFREDSTOCK and CARL SOJIIESKI(Ber., 1917, 50, 1739-1754. Compare A., 1916, ii, 319). -The experiments, fully described in this paper, had for their object the bromination of pure silane under conditions favourable to the production of the lower bromides. Under ordinary conditions, the reaction betwemen bromine and silane is very violent, but if an excess of the gas is led into a large vessel on the walls of which solid bromine is deposited, and the temperature is main- tained at about - 80° to - 70°, the mono- and di-substitution products can be obtained comparatively free from SiHBr, and SiBr,. The apparatus employed is very elaborate (see A., 1917, ii, 442) and the manipulation is a matter of considerable difficulty. For details of the preparations and final fractionations, the original should be consulted. Bronzomonosilane, SiH3Br, is a colourless gas with a pungent odour, at the same time reminiscent of monosilane. It has m. p. -94O, b. p. +1-9O/760 mm., DO 1.533, and molecular latent heat of vaporisation 5.83 Cal. It may be preserved over mercury for some time, but it detonates on exposure to the air, giving silicic acid and brown silicon. It reacts with cold water according to Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. the equation 2SiH,Br + H,O = 2HBr + (SiH,),O (see following abstract), whilst’ it may be aiialysed by measuring the volume of hydrogen produced under treatment, with 30% sodium hydroxide, according to the equation SiH,Br + 3NaOH = 3H2 + NaBr+ Na,SiO,. ~ihro?~zomo,iosiZni~e,SiH,Br,, is a colourless, mobile, highly re- fractive liquid, m. p. -70*1°, b. p. 66O/760 mm. (extrapolation; highest recorded value, 18O/123 mm.), Do 2-17, molecular latent heat of vaporisatJim 7.41 Cal. In carefully dried vessels, it may be kept for a long time, but it inflames in the air. It is very sensitive to moisture, being decomposed into hydrogen bromide and a solid, (SiH,O),. Alkalis decompose it according to the equa,tioii SiH,Br, + 4NaOH = 2H, + 2NaBr + Na,Si03 + H,O. J. C. W.

Silicon Hydrides. 111. Disiloxane , (SiH,),O ; Tetra- chloromonosilane, SiCl, ; Hexachlorodisiloxane, (SiCl,),O. ALFREDSTOCK, CARL SOMIESHI, and ROBERTWINTGEN (Ber., 1917, 50, 1754-1764) .-When bromomonosilane is shaken with water, it changes into disiToxnue, (SiH,),O, the preparation and purifica- View Article Online

INORGANIC CHEMISTRY. ii. 111

tion of which are now described. It is a colourless, odourless gas which does not inflame spontaneously, but burns with a brilliant light, giving a white smoke and a deposit of brown silicon. It has m. p. -144O, b. p. -15*2O, D-80 0.881, molecular latent heat of vaporisation 5-63 Cal. (compare SiH,, 3.03; Si,H,, 5.18; Si,H8, 7.13; Si,H,,, 9-18 Cal.). The m. p. and b. p. are lower than the constants for the parent hydride, Si,H, (m. p. -132.5O, b. p. - 15O), which is the reverse of the relationships between ethane and dimethyl ether. It only decomposes rapidly under the influence of heat when raised to redness. Submitted to a discharge of electric sparks, it slowly yields pure hydrogen. When mixed with oxygen, it inflames or explodes at once, the alteration in volume being in accordance with the equation (SiH,),O + So,= 2Si0, + 3H20. It is not appreciably soluble in water, but soon decomposes into hydrogen and insoluble products, like (SiH,O),, etc. With sodium hydroxide, however, decomposition is complete, according to the equation (SiH,),O + H,O + 4NaOH = 2Na,SiO, + 6H,, which may be applied in the analysis of the gas. Disiloxane and chlorine react very vigorously at - 125O; the primary product, hexachlorodisiloxane, may be isblated, but most of it decomposes according to the equation 4(SiCl3),O = 2Si0, + GSiCl,, and some brown silicon is even formed as well. “ Tetrrr- cJ~ZorominosiZane” (silicon tetrachloride) has m. p. - 68*7O, b. p. 56*8O/760 mm., molecular latent heat of vaporisation 7.19 Cal., and “T~exacJ~Zo~odisiZoxane”is now found to have m. p. -33O and b. p. 137O/760 mm. It is an interesting fact that disiloxane is the first volatile compound of silicon, hydrogen, and oxygen. Many derivatives, with the same elements, are known, such as “ silicoformic anhydride,” (O:SiH),O, but these must assuredly be polymerides, whereas alkyl,

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. alkoxyl, and similar derivatives of the true monomeric type, for example, (SiR,),O and rSi( OR),],O, have frequently been prepared (compare Martin and Kipping). Apparently, the compound SiH,*OH, which would be the primary product of the action of water on SiHR,Br,is very unstable. It is noteworthy that the alkyl derivatives, SiR,*OH, also change into oxides readily, but the alkyl groups do confer a measure of stability on them, for hexaphenyldisiloxane, (SiPh,),O, changes back into SiPh,*OH on boiling with alcoholic potassium hydroxide (Kipping and Lloyd, T., 1901, 79, 455). J. c“. W.

Silicon Hydrides. IV. Oxomonosilane (Protosiloxane). ALFREDSTOCK, CARL SOMIESKI, and ROBERTWINTGEN (Ber., 1917, 50, 1764-1769).-Dibromomonosiloxane reacts with water to form hydrogen bromide and a volatile compound, which is very probably oxomonosdnne (poto.siZoxane), SiH,O. The authors have not been able to isolate this, as it is about as volatile as the hydrogen bromide solution, and, furthermore, polymerises most readily, so’ that after a few distillations the whole of the origiiial silicon is found in the insoluble residues. The ldynzericle is ail amorphous, white solid, View Article Online

ii. 112 ABSTRACTS OF CHEMICAL PAPERS.

which is stable at 300° (vacuum) or in contact with boiling water, but inflames in the air or chlorine, and reacts with sodium hydroxide according to the equation (SiH,O), + 2NaOH -+ 2H2J,- Na,SiOs. J. C. W. Proof of the Production of Water in the Formation of Salts from Acid and Base. W. FRANCK(Zeitsch. physiknl Chern. Unterr., 30, 147; from Chena. Zentr., 1917, ii, 358-359). --In the experiment described by Zeitler (A., 1917, ii, 463), calcium or barium hydroxide should be used, as the alkali hydr- oxides are never anhydrous. R. V. S. The System Lithium Sulphate-Lithium Chloride-Water at 303. F. A. €I. SCHREINEHAKERSand G. M. A. KAYSER(Chent. WeekbZacZ, 1918, 15, 120--121).-The solubility of lithium sulphate in water is much diminished by the presence of lithium chloride. A. J. W. The Necessity for Applying a New Correction to the Atomic Weight of Silver. PH. A. GUYE(J. Chhi~.phys., 1917, 15, 549-560).-The author discusses the various sources of error, due to the presence of occluded gases and the adherent pellicle of moisture on the metal, in the atomic weight determinations of silver. On the basis of recent work (compare A., 1916, ii, 432), he considers that the atomic wedght, of silver should be revised to 107.87, and that the correct values for the halogens should be C1= 35.461, Br = 79.925 , I = 126.915. W. G. Metallographic Investigation of the System Zinc and Selenium, MASUMICHIKASHIGE and ROKUROKUROSAWA (Me7n.

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. CoZZ. Sci. Kyoto, 1917, 2, 245-248).-When zinc and selenium are heated together at a sufficiently high temperature, the compound ZnSe is formed. Zinc selenide has a brilliant yellow colour, DZ1 5.29, and does not fuse up to 1100O. The fused elements are not appreciably miscible, and the selenide does not dissolve in either. If a fused mixture is allowed to cool, the two free elements and the compound are detectable in the solidified product when examined under the microscope. [See Ind., 153A.I H. M. D. Metallographic Investigation of the System Cadmium and Selenium. MASUMICHIKASHIGE and RIICHIHIKOSAKA (Mem. CoZZ. Sci. Kyoto, 1917, 2, 239--244).-Cadmium and selenium combine to form the compound CdSe, which is infusible up to 1350O and has D16 5-81. The reaction between the elements begins to be appreciable at about 360°, and its velocity increases with rise of temperature. The cadmium selenide does not dissolve in either of the molten elements, which are themselves practically immiscible. When, therefore, a mixture of thel two elements is fused and cooled, the product consists of a mixture of cadmium selenide, cadmium, and selenium, which are readily recognised under the View Article Online

INORGANIC CITEMTSTRP. ii. 113

microscope. The proportion of the compound in the product denends on the temDerat’ure to which the mixture has been heated agd on the length if the period of heating. [See Irtd., 153~..] H. M. D. The System, Copper Chloride-Lithium Chloride-Water at 30°. F. 9. H. SCHREINEMAKERSand (MISS) A. C. NOORDUYN(Chenz,. IT7pcX:hlcrd, 1918, 15, 118 ----I20).-An application of Schreine- makers’s graphic method to solutions containing cupric and lithium chlorides. A, J. W.

The Critical Constants of Mercury. E. ARIES(Conzpt. retad., 1918, 166, 334-337).-Using the formula previously given (compare this vol., ii, 61) for monatomic vapours, and taking the known vapour pressures of mercury at different temperatures, the author calculates the critical temperature of mercury as 1077O and the critical pressure as 420 atmos., these values being a close approximation to the correct figures. W. G. Preparation, Properties, and Analysis of White Pre- cipitate.” I. M. KOLTHOFF(Phamz. Weekblnd, 1918, 55, 208-!218).-A comparison of the methods for preparing white precipitate” given in the Dutch, German, English, Belgian, Swiss, and U.S.A. pharmacopaeias. The author is of opinion that the Dutch method is the most satisfactory. [See, further, Ind., April.] A. J. W. The Space Lattice of Aluminium. P. SCHERRER(Physikul. Zeitsch., 1918, 19, 23--27).-The method described by Debye and Scherrer (A., 1917, ii, 437) for the X-ray examination of crystal

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. structure has been applied to finely powdered aluminium. The interference photographs afford evideiice that aluminium forms cubic crystals, and that the atoms are arranged according to a simple face-centred lattice. Measurements of the interference patterns give 4.07 x cm. for the length of the edge of the elementary cube. The corresponding values obtained from previous investigations are: copper 3.61, silver 4.06, gold 4.07, and lead 4.91 x 10-8 cm. In spite of the close agreement between the values of the lat’tice constants and of the atdmic volumes for aluminium and gold, the two metals do not form a complete series of mixed crystals. This is attributed to the preponderating influence of chemical affinity. H. M. D. The Effect of Great Hydrostatic Pressure on the Physical Properties of Metals. ZAY JBFFRIES(J. Inst. Metals, 1917, 18, 243--252).-The statement of Hanriot (A., 1913, ii, 112) that metals subjected to hydrastatic pressures of the order of 10,000 kilos. per sq. crn. are permanently hardened without deformation, is contrary to modern views on hardness. A repetition of the experiments, using aluminium and an alloy of aluminium and copper, View Article Online

Ei. 114 ABSTRACTS OF CXEMTCATJ PAPERS.

immersed in light petroleum under pressures up to 12,400 kilo. per sq. cm., shows that no increase in hardness is produced. Hanriot used vaselin, which becomes solid under very high pressures, so that the pressure applied is not hydrostatic. Experi- ments with the same metals show that a degree of cold deformation, insufficient to cause a noticeable change in the dimensions, produces a marked increase in the hardness as determined by the scleroscope. This explanation is more probable than that of the occurrence of allotropic change in the metal. [See Ind., April.) C. H. D.

Metallographic Investigation of the System, Aluminium and Selenium. MASUMICIIIKASHIGE and TSUW.JIAOKI (Xem CoZZ. Sci. Kyoto, 1917, 2, 249-254).-Cooling curve observations show the forniation of a compound, AI,Se,, which melts at about 950°. The formation of this compound by heating the two elements together is frequently accompanied by an explosion unless the mixture contains more than 90% of selenium. The compound crystallises out from all fused mixtures of the two elements, and in accordance with this, the two branches of the compound curve on t'he freezing-point diagram cover the whole of the region from pure aluminium to pure selenium. The eutectics are therefore very nearly coincident with the freezing points of the two elements. The microcrystalline structure of solidified mixtures is in agreement with the thermal data. Aluminium selenide decomposes in contact with moist air with the formation of hydrogen selenide and aluminium hydroxide. [See Znd., 153~.] H. M. D.

Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. Metallographic Investigation of the System, Tellurium and Aluminium. MASUMICHIKASHIGE and JITSUZONOS& (Menz. CoZZ. Sci. Kyoto, 1917, 2, 227-232).-When aluminium and tellurium are heated together, combination takes placel with ex- plosive violence, and the compound Al,Te,, m. p. 895O, is formed. This telluride forms mixed crystals with tellurium, the series extending from the pure compound (12.4%by weight of aluminium) to a mixture which contains 4.4% of aluminium. On cooling, the a-mixed crystals undergo transformation into &mixed crystals. The temperature atl which this conversion takes place diminishes with increase in the tellurium content, and for the saturated &mixed crystals falls to 541O. The j3-mixed crystals and tellurium co-exist at the eutectic temperature 414O, the eutectic mixture containing 2.8% of aluminium. The freezing-point curve of the compound A1,Te3 on the aluminium side is terminated by a eutectic point, in which the telluride and aluminium co-exist in equilibrium. The eutectic mixture contains 970L of 'aluminium and the eutectic temperature is 621O. The conglomerates, consisting of the telluride or aluminium and the enkectic, undergo transformation when ths temperature has View Article Online

TNORGANTC CHEMISTRY. ii. 11.5

fallen to 551°, with the formation of AljTe, according to the equation A1,Te3 + 13A1= 3A1,Te. The telluride, Al,Te,, is energetically decomposed by water or by contact with moist air, with the formation of hydrogen telluride and aluminium hydroxide, according to the equation Al,Te3 + 3H20= 3TeH, + Al,03. The compound A1,Te is less readily decomposed, but hydrogen telluride is liberated in contact with water, the reaction being possibly represented by A15Te + H,O + 0, = TeH, + A1203+ 3A1. Microphotographs are given which afford evidence in support of the results obtained by the thermal analysis of the system. [See Id., 153h.l R.M. D. A Criterion for Allotropic Transformations of Iron at High Temperatures. K~TARGHOWDA (Sci. Rep. TohoIm Imp. 77nizl., 1917, 6, 213-2117).-The transformations of iron consist in part of allotropic changes which take place at a definite temperature and of gradual changes in which the equilibrium con- dition is a continuous function of the temperature. The available data relating to these transformations show that A, is of the second type, whilst A, and A, are allotropic changes. In the case of carbon steels, there are in addition the changes designated by A, and A,, the former representing a gradual change in cementite, and the latter a eutectic transformation of cementite and ferrite which occurs at a definite temperature. H. M. D. The Micro-structure of Commercially Pure Iron between Ar, and Ar,. W. J. BROOKEand F. F. HUNTING(J. Iron Steel Znst., 1917, 96, 233-250).-Armco iron, a basic open-hearth product containing as much as 99.84% Fe, passes through a character- istic brittle range between 900° and 800°, but only during cooling, Published on 01 January 1918. Downloaded 28/10/2014 04:37:21. no change being observed within this range during heating. Quenching experiments show that a eutectic or eutectoid structure appears between these temperatures, but is absent' either above or below the brittle range. This constituent, resembles pearlite in structure, but is not related to the carbon content, and is also independent of the quantity of oxide in the iron. Heating in hydrogen is without influence on the structure. Similar results are obtained with Swedish iron containing about 0.04% of carbon. [See, further, Znd., 1917, 1096.1 C. H. D. The Nature of Subsidiary Valencies. XVII. Prediction of the Decomposition Temperatures of Ammines. FRITZ EPHRAIMand ELIASROSENBERG (Ber., 1918, 51, 130--136).-1t was recently shown that the ratio of the temperatures cf dissociation for certain pairs of compounds of two elements is roughly constant (A., 1917, ii, 531). If the dissociation points of a number of compounds of one element are known, and the ratio has been determined in the case of one pair of corresponding compounds for another element, then the; dissociation temperatures of all the other compounds of the second element can be predicted. This is illus- View Article Online

ii. 116 ABSTRACTS OF CENMICAL PAPXRS.

trated further in the case of the hexammines of nickel and cobalt salts. The ratio, or I' temperature-modulus of the tension," calculated from the dissociation temperatures of the iodides, is NiICo, 1/1*075(A., 1912, ii, 546). Dividing the known temperatures for other nickel salts by 1.0'75, therefore, gives approximately the dissociation points for the corresponding cobalt salts, In the cases of the hexammines of ths bromides, nitrates, dithionates, chlorides, sulphates, acetates, and hydrogen carbonates (descending order of stability), the calculated values agree with the observed ones within thel limits of the experimental errors. Most' of the hexammines mentioned have been described before (A., 1913, ii, 496, 1061), but the following are new: cobalt- hexnmmine nitrate, by warming the crystalline nitrate in ammonia gas, dithionate, hypophosphite, formate, and acetate ; the dissociation temperatures are respectively 160°, 157*5O, 51°, 21*5=', and 55.5O. J. C. W. Metallographic Investigatiw of the System, Selenium and Antimony. MASUMICHI~ASHIGE and' MASASUKEFUJITA (Mem. (2011. Sci. Kyoto, 1917, 2, 233-237).-Cooling-curve data show that' antimony and selenium form a compoupd, SbnSes, melting at' 572O. With antimony, the cornpoupd forms a eutectic mixture containing 46.5% of selenium, the eutectic temperature being 497O. The eutectic on the selenium side of the compound corre- sponds very nearly with pure selenipm melting at 211O. Microscopic investigation of solidified mixtures of the two elements confirm the results obtained in the thermal analysis. [See hd., 153~.] H. M. D. Published on 01 January 1918. Downloaded 28/10/2014 04:37:21.