166
GENERAL, PHYSIC.fL AND IXORGANIC.
brown iron ore, 2.0; total, 100. The analysis is certainly far from satisfactory, The second analysis is ‘tty Carnot‘ who gives 96.70 per cent. Bi,O, with the remainder distributed m-er eight compounds, including 0.95 per cent. H,O, also SOj, EICI, CO:, etr. While indicating the probable presence of Bi,O,, the existence o i the simple oxide can hardly be considered as established by the analy3is of Carnot. 9 s the first natural crystals of bismite described do not agree? with those artificially prepared, i t seems doubtful whether Bi,O, actually occurs in nature. The apparent identity of the natural crystals described by Rogers3 with the artificial crystals of Bi,O, is rendered somewhat questionable by the lack of chemical data on his crystals and by the evidence of the composition of the San Diego County ochers, as shown in this paper. Summury.---The chief points brought out in this paper may be briefly summarized as follows : ( I ) The existence of natural Bi,O, has not been established. (2) Natural bismite or bismuth ocher, when pure, is more probably a bismuth hydroxide. ( 3 ) The bismuth ochers from San Diego County, California, are either a bismuth hydroxide or bismuth vanadate, pucherite, or mixtures of these two. (4) Pucherite has been found noncrystallin and determined for the first time in the United States. u. s.
CHEMICALLABORATORY, GKOLOGICAI, S U R V E Y , U ’ I S H I N G T O N , r)
c.
RECENT WORK IIB INORGANIC CHEMISTRY. BY JAS. LEWIS HOWE. Received December IO, 1910.
The problem of chemical formulas and nomenclature of inorganic compounds, with especial reference to indexing, is discussed by N. I-Frankforter, Roehrich and Manuela to be very complex, the evolved gas containing not merely nitrogen as assumed by Ramon de Luna, but also nitric oxide and even nitrogen dioxide. In one case as much as 45 per cent. N O was obtained. The composition of the residue also depends upon the composition of the original mixture. The complexity of the reaction is attributed to the fact that the ammonium chloride dissociates into ammonia and hydrogen chloride, and the former diffuses out of the mixture more rapidly than the latter. Hayhurst and Pring" have examined the atmosphere a t different elevations for the presence of nitrogen oxides and ozone, by passing the air through a perfectly neutral solution of potassium iodide, and determining the liberated iodine, the free alkali and the iodate formed, They find that a t low and a t moderate elevations the amount of nitrogen oxides is very variable and that the amount of ozone is not sufficient to determin, at all events less than 0.003 mg. per IO cu. m. At the height of I O miles small amounts of ozone are found, 0.04 mg. in from 0.1to 0.3 cu. m. The amount of nitrogen oxides is here less than the amount of ozone. Adwentowski? has studied nitric oxide a t low temperatures, Bw., 43, 1027 Ann., 375, I . Ber., 42, _I
'
4222 ; 43,
2286.
Tars JOURNAL, 3 r , 637 Ibzd., 32, 178 J . Chem. SOC., 97, 868. Anz. Alnzd. Wiss. Krahzc, 1909,742
RF$CENT WORK IN INORGANIC CHEMISTRY.
I75
and from the vapor-pressure curve concludes that at high pressures the gas is somewhat polymerized. It is, however, completely dissociated a t atmospheric pressure. The melting point of the solid NO is -160.6' with a pressure of 168 mm. The boiling point at 760 mm. is - 1 5 0 . 2 O , the critical temperature -92.9' and the critical pressure 49,095 mm. The bluish color of the solid and liquid is attributed to the presence of a little N,O,, which it is impossible to remove. Numerous articles by Haber and his colleagues have appeared in Vol. 16 of the 2. Elektrochem. on the formation of the oxides of nitrogen from the atmosphere in the electric arc under various conditions, and Guye has reviewed the whole subject critically in the BuZl.~soc.chim., [4] 5, No. 20. The papers are of great interest in connection with the rapidly developing synthetic nitrate industry, but do not admit of abstraction. Guntz and Martin' have prepared the anhydrous nitrates of manganese, nickel, cobalt and copper by the use of N,O, in a vacuum for the removal of the last of the water of crystallization. By the action of metals on AgNO, in nonaqueous solvents, the nitrates of the above metals are obtained, combined with the solvent, as 5Cu(N0,),.4CH,COCH3 and nMn(NO,),.C,H,CN. In liquid ammonia, Mn(NO,),.gNH, was obtained and analogous compounds of nickel and cobalt. With copper, Cu(N0,),.7NH3 was formed, which in a vacuum became Cu(N0,),.4NH3. Several papers on elementary phosphorus have appeared during the past year, whose results are not in complete agreement. Gernez, has examined the coating which appears on ordinary yellow phosphorus when kept under water. This coating is white when formed in the dark but yellow to red when exposed to the light. In both cases, however, it is composed of ordinary yellow phosphorus. Phosphorus oxidizes slightly under water and the oxide formed dissolves in the water leaving the surface covered with phosphorus in minute flakes which causes the opaque appearance. According to JoliboisS the red phosphorus of commerce can be separated into larger dark violet and smaller yellowish red particles, but the violet are changed into the yellowish red by rubbing and are not a distinct modification. If the violet particles are heated out of access of air to 400' they pass slowly into a new modification, which Jolibois calls red pyromorphic phosphorus. The change takes place rapidly a t 6ooo, and it is also accelerated by the presence of iodine. This modification has a density of 2.37 and is a definit allotropic form. On the other har:d, Cohen' finds only two modifications of phosphorus, the ordinary yellow and the "metallic" or Hittorf's phosphorus. The red or amorphous phosphorus of trade is a solid solution of yellow phosphorus in metallic phosphorus. The composition of this solid solution is a function of the temperature. The so-called constants of red phosphorus found in its literature have no value. Stock6 has made a very complete study of the metallic phosphorus, which also according to him is the only modification of phosphorus except the ordinary yellow form. The metallic phosphorus is best prepared by dissolving phosphorus in metallic lead
.
Bull. sac. chim., [4] 5, 1004;7, 313. 2 .inn. chim. phys., [SI 21, 5 . Compt. rend., 149, 287. * 2. physik. Chem., 71, I . Bey., 42, 4510.
l?h
GENERAL, PHYSIC.\-
Wlj INORGANIC.
and separating the lead by anodic solution in an acetic acid solution of lead acetate. By usinq 100 grams lead and 1 . 5 grams of phosphorus, about 0 .j gra nietallk phosphorus can be obtaineci. 13ismuth can be substituted for lead. atid 11 liile better cr5 stals are obtained the outh b v sublimation. put is smaller. i t C'CLTI also be prepared ) \ ~ t rlifficui!\~ Under the microstope the metallic piiosphorus IS seen to ccrnsist of vellow to brown, niore or less transpaient tables. rvith some acicular cr>stals. Thev contain small quantities n l lead (or bismuth), apparently in solid solution. IVhile ordinary yellov- phosphorus m i t e s s1w.s lv with sulfur to form phosphorus sulfide, the metallic phospliorus hardly reacts with sulfur. I t oxidizes slowly in tlre air. anti that formed by sublimation oxidizes as soon as the tube in which i t was formed is opened. [I'he nomenclature of phosphorus is ciuch in need of revision. \\'e nox have "common," "white" or ' >ellow" phosphorus: "red "or "amorphous;" and "metallic," "crystallin, '' ~ i o k t , ' or "i-iittorf's" phosphorus; and not one of these names is wholly satisfactory.-~Ev~EwER.] Gernez' has also examined the so-called ' 'black" phosphorcs discovered by Thenard in 1812. Il'hen mercury is dissolved in phosphorus the solution is colorless and if saturated or supersaturated, it remains colorless. Wheii it crystallizes the mercury separates out and colors the mass intense black. l'he mercury is then so finely divided that, on warming, the fused phosphorus imniediatelv redissolves the mercury again to a colorless solution. Stock' has continued hi5 work on the sulfides of phosphorus, completing his description of tlie properties of P$,. and also of P,S,,, which has not before been obtained in a pure condition. The latter boils a t 513~-515' with bome decomposition, and a t 600' its density corresponds to the formula I>$,. It is interesting to note that as regards color, specific gravity, melting and boiling, points, solubility and stability, P,S,, so far from standing intermediate between P,S, and P4S10,lies entirely outside the other two. This much simplifies the problem which Stock has before him of investigating other sulfides of phosphorus, which he feels certain esist. R s submitting a mixture of phosphorus trichloride and hydrogen to the action of an electric discharge, Besson and FournierJ obtained the dichloride, P2C14,a colorless oil, solidifying a t low temperatures to a v, hite mass, which fuses a t ---2So. I n the presence of at1 indiflerent gas i t boils a t 160' with slight decomposition. The compound is rather unstable and gives deconiposition products which ha\ e not yet been investigated. Zheniciiuzhnuii and Shepelev,' prepare nietallic phosphides by mixing the finely divided metal with red phosphorus and throwing the mixture in small lumps into a hot crucible. Some of the phosphoius burns whde the rest unites with the metal. The melt is cos-ered with a protecting layer of barium chloride and the temperature raised. Red phosphorus is then added in asbestos capsules, and more metal and phosphorus as desired. The mass is then investigated as an alloy. l n this may but a single phosphide of cobalt is found to esist, Co,P. which, howexer. is found in LWO distinct modifications. * C ovsp . r m d , 1 5 1 , 12 '
COWL@.
7
i r , ~ d 150, . ~ 102.
Chtrn , 64, 245
~ Z J Z O ~ ~
RECENT WORK IN INORGANIC CHEMISTRY.
I77
The action of phosphorous and hypophosphorous acids on metallic salts has been studied by Sieverts,’ who finds that cupric salts alone are reduced to a hydride by hypophosphorous acid. The,oxidation of the acid to phosphorous acid corresponds to the accepted formula, CuH. Phosphorous acid reduces copper sulfate to metallic copper. Cupric chloride is reduced by both acids to cuprous chloride. Gold and silver salts are reduced by both acids to the metal and the same is trde of palladium, while platinum chloride is not affected, nor are the salts of nickel and cobalt. More work has been done on hypophosphoric acid by Cornec,2 who proposes as a better method of preparation, placing sticks of phosphorus between glass rods on the corrugated bottom of a developing tray, and partly covering with water. The tray is covered with a glass plate, and by putting ice on this the temperature can be controlled, if necessary. From cryoscopic determinations of the acid and its salts, Cornec inclines to the formula H4P,06, though the esters seem to have the simpler formula. Rosenheim3 prepares hypophosphoric acid by a modification of a process proposed by Cornec, allowing yellow phosphorus to react with a solution of copper nitrate containing considerable nitric acid. The copper nitrate can be replaced by silver nitrate, but not by the nitrates of other metals, since the catalytic action of the copper or silver seems to be necessary. Good results were also obtained by the anodic oxidation of copper phosphide, while iron phosphide gave only phosphoric acid. The hypophosphoric acid is separated as the acid sodium salt, NaHP03.2H,0, which is but slightly soluble. Guanidine carbonate is the best reagent for the detection of hypophosphates, forming a very slightly soluble salt, (CN,H,),.H,PO,. jH,O. By this means it may be detected in mixtures of other phosphorous acids. The boiling point determinations of benzylhypophosphate in ether confirmed the results previously obtained with the methyl and ethyl esters and indicate the simpler formula as, correct. The same was true of conductivity determinations of the acid. Kosenheim concludes that while the formula of the acid is II,PO,, it has a strong tendency to association in aqueous solutions, which accounts for the results obtained which seem to point to the formula H4P208. Schmidlin and Massini4 have prepared by the action of phosphorus pentoxide on hydrogen peroxide a phosphorus “monoper acid” analogous to the Car0 acid, and possessing similar properties. Its formula is H,PO,. If sirupy pyrophosphoric acid in large excess acts on hydrogen peroxide, a perphosphoric acid is formed which from analogy has the formula H4P,0,. Several hundred crystals of struoite are recorded by Boggild as havings been found in a well I O to 35 meters deep, on Limfjord. The deposit contained many .shells of mollusks and vegetable remains. The crystals were from I to j cm. in diameter and I to 5 mm. in thickness. Ephraims has prepared barium and magnesium mono-oxy- trithiophosphates and barium dioxydithiophosphate (Ba,(PS30),.2oII,Q and Ba,(PS,O,),. 18H,O) by the restrained
‘ 8
Z. anorg. Cltem’64, 29. Bull. .TOG. chint., [4] 5, 1058, 1081, I 1 2 I . n e r . , 43, 2003. Ibid.,43, 1162. Nezies Jaltrb. M i x . Geol., 1910,i, 335. B e y . , 43, 285.
GENERAL, PHYSIC * 1, AND INORGANIC.
178
action of barium (or magnesium) sulfide on sodium (tetra) thiophosphate. He has alsc, preparedl a number of oxy-selenophosphates, but apparently the mono-oxytriseleno and dioxycliselenupiiosphates form isomorphous ixixtcres. Ii vias not foii-14 ~ J O ~ ~ ;I) L Pe i m e the telr'tselenophosphates in solid form. Steel describes2 a deposil of feat;ierTr Idatec of pearl? :rhi!e luster of As,@,.SC), fourlcf in tke iron sight tubes of a sulfur burner a t Clyde, New South n'ales. The burneis used Japaiiese stilfur with a content of about 0.005 per cent. arsenic. The cry5tals 11ere \-en' hygroscopic and instantly deconiposed by wafer. Ephraim has repealed" the ivork of Gibbs on the arseno-nmlybdates and falls io obtain an, oi' the compounds made by : S : 13 ratios, but has preGibbs which had 3 . . 12 : 23 and 3 pared salts of potassium with 3 : I : j : 3 and 3 : I : 8 : 18 ratios, and sodium salts with I : I : 2 : 6 and 2 : I : 4 : 13 ratios, as well as ammonium barium and ammonium copper salts. A new type of compounds is described by l i ~ i i containing ,~ SbF, and SbCl, in the ratios 3 : I , 2 . I, 1 : I, 2 : j, I : 2 , and I : 3. These are lormed by direct mixture or by t h e actiori of chlorine on a mixture of SbF3and SbCl,. They seem to be defir,it compounds, and the two constituents of the compounds are considered by Ruff as acting as elements, the affinity of SbF, lying between that of fluorine and chlorine while that of SbCl, is as strong as that of bromine. The affinity between the two constituents may be therefore considered as equal to that existing between fluorine and bromine. or between chlorine and iodine. He likens these compounds to such a5 XgI.AgN@, and CaF,.CaCI,. Ephraim6 has made a study of the double halides of quadrivalent antimony, and conclades that the equilibrium SbC1, ,ChC1, _I2SbC1, is to a great extent dependent on the teniperattm and the possibility of ionization. Ile has also prepared triple salts containing E'eC1, with quadrivalent antimony, and a number of salts of the alkylammonium halides, with trivalent and xith yuiiiquivalent antimony. The solubility of bismuth sulfide in alkali sulfides and bismuth oxide in the alkalies has been re-investigated by Knox,e who finds that the sulfide is somewhat soluble in E;$ and Na,S, the solubility increasing nearly proportionally to the third power of the concentration. This is accounted for bq assuming the rsisterice of a thio-bismuthic anion, The sulfide is insoluble in the hydrosulfides and in the higher polysulfides. I n the disulfide it is only one third as soluble as in the monosulfide. 111 ammonium sulfides i t i s practically insoluble. X slight solubility was found for bismuth oxide in sodium hydroxide. These rewIts correspond to the position of bisrnuth in the periodic table. Prandtl and Eleyer' have tried to prepare pure metallic vanadium by reduction of the pentoxide with aluminium or calcium-aluminium by the GoldSchmidt procecs. The best results are obtained bv using a l
o
7
L~
-
B c r , 43,
7
277
Soc- Ch6vi
It
ti
. 29, 1142
Z. anorg. Ck m., 66, 53 a
Bel., 42, 4021. Ibid., 4447 LT Ciwin. SOL.,95, 1760 7 ntiorg. Chem., 64, 2 1 j .
Bel., 43, 2 6 0 ~ .
ReCENT WORK IN INORGANIC CHEMISTRY.
I79
fluorspar lining for the crucible or by adding fluorspar to the mixture, but in no case was a vanadium more than 95 per cent. pure obtained. As the ordinary impurities were absent, the result can only be accounted for by the presence of a lower oxide of vanadiuri , which alloys itself with an excess of the metal and so is protected from the action of the reducing agent. A long paper by Weiss and Landecker' has appeared on the preparation and separation of columbic and tantalic acids, in which they describe critically the action of many reagents and methods of separation. To separate the metals they prefer to fuse with sodium carbonate and a minimum of saltpeter. The columbate melt is easily soluble in water and not precipitated by CO,, while the tantalate melt is far less soluble and is precipitated by CO,. Hence they warm the melt with very little water and wash the tantalate residue with sodium bicarbonate solution. Any columbate that goes into solution is precipitated by CO, and brief boiling. The tantalate residue is free from columbic acid, and is dissolved in sulfuric acid with the addition of hydrogen peroxide, from which the tantalum is precipitated by SO,. If care is used as to temperatures and quantities of reagents, they claim that the separation is practically complete. The investigation of the halides of tantalum a t the University of. Pennsylv nia laboratory has been continued., Chapin applied the process by which ChabriC obtained the dichloride, TaCl,.zH,O, to the bromide, heating the pentabromide with sodium amalgam in a vacuum. The bromide obtained has the formula Ta,Br1,.7H,O. While the dichloride is green, this bromide is black, but gives a dark green powder in a mortar. Its solution is almost opaque. Only two atoms of bromine are precipitated by silver nitrate, and these may be replaced by other negative radicals, so that Ta,Br,, proves to act as a bivalent base. A re-investigation of Chabrie's chloride shows that it also has a complex formula, being really Ta,Cl,,.Cl,.zH,O, analogous to that of the bromide. Van Haagen finds that TaBr, is readily formed by heating the oxide with carbon in a current of dry bromine, fuses at 240' and It dissolves in absolute methyl and ethyl alcohols with boils at 320'. which it seems to form esters. Lower bromides, except the one described above, could not be prepared. The pentaiodide was made by distilling the bromide repeatedly in a current of hydrogen iodide. No oxy-iodide was found. Biltz3 has prepared the sulfide of tantalum, which has the formula TaS,, by heating the oxide in a stream of H,S saturated with carbon disulfide. The reaction begins a t 650' but is not complete at 900'. The sulfide is stable up to a t least 1300°, but is hygroscopic and decomposes in warm, moist air. Biltz conjectures that the formula for the sulfide of columbium should also be CbS,. G ~ o u pVI.-In connection with his work on the conditions of existence of matter,' von Veimarn describes the preparation of colloidal ice5 by the sudden cooling in liquid air of saturated solutions of numerous salts, such as various thiocyanates, calcium chloride, aluminium sulfate, ferric Z.anorg. Chem., 64,65. THISJOURXAL, 32, 323, 729. Rer., 43, 1636. 2. C h m . Ind. Kolloide, 3, 282. ' J . Rum. Phys. Chem. SOC.,42, 65,69.
GgNERAL. PHYSICAL AND INORGANIC.
I80
chloride, etc. I n this way are formed completely transparent and stable glasses which contain solid solutions of ice. By adding small quantities of nater to liquid air the water assumes in part a semi-solid condition, g drcps of l i q u d air to water the d r o p become co\Tered ic.e iwrxbr;trw U‘olfgang < ktwald’ cliscusses the subject n b c i cct!’ioidai ice iolutions obtained by cooling dilute er in oiqanic soivents such as toluene, xylene, etc. These solutions m a t be made more stable by the addition of protective colloids as ina:,tic, o r the aluiriinium salts of the fatty acids. They have a yellowish blue fluorescence and pass unchanged through the finest filter paper. Jones has continued his nork on hydrates in solution,2 with especial reference t o the temperature coefficient of conductivity, and finds further confirmation of the theory that the change in conductivity with the temperature is largely due to the decrease in complexity of the hydrates. The water of crystallization of many salts has been studied by Masson3 by mixing with calcium carbide, and collecting the evolved acetylene over mercury. ZnS0,.7HL0, for example, loses five molecules of water in the cold, and one further molecule a t roo’. Ammonium iron alum goes over in the cold into the trihydrate and a t 1 4 j O into the monohydrate. Ammonium aluminium alum and common alum lose IO.? molecules of water a t 130°-160”, etc. By pouring liquid sulfur a t 400’ into liquid air, von Veimam’ obtains threads of sulfur which are hard and brittle but which when the temperature rises become remarkably elastic. At ordinary temperature they pass rapidly into common plastic sulfur. He regards sulfur as presenting an especially good example of the tendency of those substances which can exist in numerous modifications to give most readily colloidal forms. Gardner and IIodgsons have investigated the tendency of wool. dyed with sulfur blacks to deteriorate, especially in warm climates. They find that by boiling with ether it is possible to extract considerable quantities of sulfur from the dyes, alone, or on the fiber, and it is the ready oxidation of this finely divided sulfur that weakens the wool. No dyeing procedure obviates this difliculty, which proceeds from the decomposition of the dyestuiT itself, in which the sulfur seems to be loosely combined. They find also that from “pure” antimony sulfide of commerce upwards of 25 per cent, of sulfur can be extracted by ether in 24 hours. This is quite in line with investigations of Jordiss on sulfides, in whiclr he finds that sulfur can be more or less readily extracted, and this. whether working on sulfides formed by precipitation or by fusion. The conclusion is that sulfides, while definit in composition, nevertheless hare their sulfur somewhat loosely combined, and it is given up t o solvents more or less easily. Precipitated sulfides are, however, often if not generally, of indefinit composition, The ready formation of sulfuric acid in precipitated sulfides is not due solely to free sulfur which may be present, but to sulfur liberated from the sulfides. L C!wm 2,id Koiloick. 6, Am. Lhe7??.g 43, 114;
183.
7 . Chmn. Soc., 97, 851. Z. ChcnE. Ind. Kol o d e , 6 ,
250
C h i n I d . zq, 672 I L i 7 g P v ’ CRPrn , 23, c
Sur.
RECENT WORK IN INORGANIC CHEMISTRY.
181
The stability and decomposition products of silver sulfite have been studied by Baubigny. Contrary to the ordinarily accepted view that in boiling water the sulfite decomposes into silver sulfate and metallic silver, he finds that silver dithionate is the principal product of the decomposition. Only a t higher temperatures, as 200°, are any considerable quantities of sulfate and SO, formed, and these come from the decomposition of the dithionate. The same is true even when the alkali sulfite is in large excess. Precipitated silver sulfite has the normal formula Ag,SO,, and is scarcely soluble in water (less than I : 20,000). I n the dark the precipitate is stable, but gradually darkens in the light. To determin the dithionic acid the evaporated solution is heated with sodium carbonate and saltpeter, since, neither aqua regia nor bromine oxidize it completely to the sulfate. This decomposition confirms the formula H,S,O, (and not HSO, as held by Kolbe). It also furnishes a new argument for the asymmetrical formula, H.SO,.OH, since in the It agrees also with the silver salt the two silver atoms act differently. asymmetrical formula for thiosulfuric acid, HS.SO,.OH. According 'to this view, dithionic acid is to be looked on as disulfonic acid, HO,S.SO,H, sulfurous acid as hydrogen monosulfonic acid, H.SO,H, thiosulfuric acid as the monosulfonic acid of hydrogen sulfide, HS.SO,H, and benzene sulfonic acid as the monosulfonic acid of phenyl, C,H,.SO,H. The last is monobasic, while sulfurous and thiosulfuric acids are dibasic, since in these latter there is retained a typical hydrogen atom of the original H, and H,S molecule. The reaction between sulfuryl chloride and ammonia, first studied by Traube and Hantzsch, has been further investigated by Ephraim and Michel., Instead of the expected sulfamide, SO,(NH,),, a series of much more complicated imides is formed whose formulas can be expressed by NH,. (SO,.NH),.SO,.NH,. These compounds give silver salts in which the hydrogen is partly or completely replaced by silver. In other efforts to prepare sulfamide, the chloroamide of sulfuric acid, ClSO,.NH,, and the ammonium salt of chlorosulfuric acid, ClSO,.ONH,, were formed, both hitherto undescribed. The best results in the preparation of sulfamide were obtained by the method proposed by Ruff, where sulfuryl chloride is slowly dropped into liquid ammonia. A mixture of the ammonium salt of imidosulfamide, NH. (SO,.NH,),, and ammonium chloride is first obtained, which after acidification is gently evaporated to dryness. The ammonium imidosulfamide is converted by hydrolysis into amino sulfuric acid and sulfamide, the latter being extracted by dry acetic ester, from which it crystallizes in great purity. Pellini, finds but one compound of mercury and selenium, HgSe, which is formed slowly and in an impure condition by rubbing the elements together in a mortar, but better by heating molecular quantities under pressure to 55o0-6oo0, or by heating mercury with an excess of selenium a t ordinary pressure. By rubbing together mercury and tellurium, the telluride, HgTe, is formed more readily than the selenide, but the compound is less stable and decomposes in a vacuum at 370'. According to Olivari4 the molecule of selenium in fused HgCl, solution varies from Comfit. read., 149,735, 858; 150, 973. Bull. B e y . , 42, 3833; 43, 138. a Atli accad. Limei, Rome, [5] 18, ii, 211. a
Ibid., 94.
SOC.
chim., [4] 7, 4,5 1
I82
GENERAL. PIITSIC.\L AND INORGANIC.
Sc, to Se, when t h e colution is dilute, hut in more cotzcentrated solutions tends tormrtl Se, In CiniiLtr solution the S, molecule shows greater ytabilit\ Tc4urir:in. ;vhen hcatri? with rnrrcitric chloride, reacts, with Irn7estigatiori by Heckmann' renders thc fortnation of !i rCI r:nd T e i l tf ')rCl, hinii:T mipi obablt., lv t n o chlmdes 0 selei l l ~ , xStCl l 1-::lik< the tiitli sulfur, StC, is by far le. 11 mmiiiie slid se are f o i mecl niirtures of k i L { i , a?:d SeHr, it 110 Se13r2 \i.liile boiling point determinations sulfur iri 1,romine is P,,selenium has under the same \\'lien nqueoiis utions of KSeCN atomic molecule and Pritze? find and tIgC12 rcact in the proportion of 2 I , Koserihe itil
that EIg(SeCh ) 2 is precipitated in white needles, which are decomposed b y hot waier Tiith the separation of selenium If the proportion IS I : I , i I> precipitated in yellow needles, soluble in ahsolute the proportiou is 3 : I . E;lig,SeCN), crvstallizes out as les, someuliat solublc in n-ater. nhile if the proportion is + I , &Hg(SeCX), is iormed, easily soluble in water and alcohol, crys; tdli7Iilg from absolute alcohol in amber plates. Crystallin CoHg(SeCK), and ZnHg(SeCS) I were formed by double decomposition from the potassium salt, showing the existence of the complex anion Hg(SeCN),--, ant1 thus indicating the relation of the selenocyanates to the thiocyanates. No coinpks salts containing cobalt (biyalent) or trivalent iron or chromium could be formed. From a iolution of mercuric nitrate, sodium selenite precipitates 1 he rnercur! salt, HgSeO,, as a white crystallin powder, which is ier! soluble m a solution of sodium selenite, with formation of 3a211g(Se
