ANTIMONY.— Sulphides. 247

From its easy fusibility, it is used to promote thisquality in many alloys which are employed for artisticor manufacturing purposes.

Antimony forms compounds with oxygen, sulphur,and chlorine, in various proportions, as seen in thefollowing table:—

Antimonious oxide (trioxide of antimony),. Sl> 2 0 3 .

Antimonoso-antimonic oxide (tetroxide, or neutral

oxide of antimony). Sb 2 0 4 .

Antimonic oxide (pentoxide, or acid oxide of

antimony), . Sb 2 0 5 .

Antimonious sulphide (trisulphide of antimony),.. Sb 2 S 3 .

Antimonic sulphide (pentasulphide of antimony),. Sb 2 S 5 .

Antimonious chloride (trichloride of antimony),.. SbCl 3 .

Antimonic chloride (pentachloride of antimony),.. SbO] 5 .

It also unites with bromine, iodine, and selenium.

Of the preceding compounds, the trisulphide,trichloride, and trioxide, are the only importantbodies in a manufacturing point of view. They are,with the exception of the trisulphide, which is em-ployed to prepare the metal, almost exclusively usedin medicine. These will now be described.

Antimonious Sulphide.— Trisulphide of antimony,anhydrous sulphantimonious acid, crude antimony, anti-mony ore, schiccfelspiessglanz, anderthalb, schwcfelspiess-glanz rohes antimon, German; stibium sulphuratumnigrum, lupus metallorum, Latin . Formula, Sb 2 S g .

Having already described the principal use of thisantimonious compound, and the method followed forpurifying it, nothing further remains but to add afew words on the manner in which the pure trisul-phide is prepared for other purposes. The trisulphidehitherto described contains, even after careful flux-ing, variable quantities of sulphides of iron, lead,copper, and arsenic; hence the black streak whichthe fused compound makes, instead of a blackishred, which is formed by the pure substance. Crys-talline antimonious sulphide may be prepared byfusing 13 parts of pure antimony and 5 of flowers ofsulphur (sublimed sulphur) in a crucible, the mixturebeing introduced by degrees and at short intervals.After the whole has been fused the crucible is takenfrom the fire and inverted, to allow the melted sul-phide to flow out. The whole of the metal may notbe decomposed in this operation, but those portionswhich have escaped the action of the sulphur areeasily removed.

Pure trisulphide of antimony, as thus prepared bythe first method, lias a steel-grey colour, a shiningmetallic lustre, and a fibrous crystalline texture ; itis brittle, and gives a reddish-black streak uponpaper; it is very fusible, but less so than the metal,boils at a high temperature, and partially distils in acurrent of gas. When heated to whiteness in a cru-cible it loses from 10 to 12 per cent, of its weight ofsulphur; heated in the air, it suffers decomposition,giving off its sulphur in the form of sulphurous acid,and absorbing oxygen, which converts it into trioxideof antimony.

A current of hydrogen gas passed over it at a lowred heat completely desulphurizes it, leaving puremetal. This property of hydrogen, that of deprivingit of sulphur at a red heat, is possessed also by manymetals, of which the most energetic is iron. When

exposed with charcoal to a white heat, the antimoni-ous sulphide is likewise reduced to metal.

When the trisulphide and trioxidc of antimonyare fused together, combination takes place, withouteither of the compounds suffering decomposition.

Its chief use, besides its employment as a sourcefor the production of the metal, is for pharmaceuticalpreparations, chiefly tartar emetic.

Amorphous Trisulphide of Antimony; Kcrmes Min-eral; brown-red sidphide of antimony; Pulvis carthu-sianum, sidphnr stibiatum rubrum. —■ Amorphoustrisulphide of antimony may be made by variousprocesses. For instance, by conducting a streamof sulphuretted hydrogen gas through a concen-trated solution of tartar emetic (potassio - anti-monious tartrate, K(SbO)C 4 II 4 O 0 ), an orange-rpdprecipitate is formed, which is the sulphide in ques-tion. When Icermes mineral is digested for sometime with tartaric acid, any antimonious oxide orpotassium salt which may be present is removed,and pure trisulphide of antimony remains. Again,by digesting a mixture of 1 part of crude trisul-phide of antimony with 1 part of pearl ash (crudepotassium carbonate), 1^- of slaked lime, and 15 ofwater, in a closed vessel for two hours. During thedigestion a soluble double sulphide of antimony andalkali is formed; and on adding sulphuric acid todecompose the alkaline sulphide, sulphide of antimonyfalls down; this precipitate is then filtered, washedwith sulphide of hydrogen water, and dried.

Fuchs obtained pure amorphous sulphide by fusingthe grey trisulphide of antimony, and then coolingthe vessel suddenly by immersion in cold water.Liebig, as will be seen in a subsequent process, con-verts the crystalline native sulphide into the amor-phous variety by dissolving it in an alkaline ley, andprecipitating by an acid; or by igniting 1 part ofantimony with 2 parts of a mixture of 1 part nitrewith 2 parts cream of tartar, extracting with water,filtering whilst hot, and precipitating the filtratewith an alkaline carbonate.

Mineral kermes varies in composition according tothe process by which it is prepared. Some of theprocesses yield pure trisulphide of antimony, othersa compound of antimonious sulphide and oxide,whilst that investigated by Berzelius and Hose con-tained sulphantimonite of potassium or sodium.

The oldest method of making mineral kermes isthat described by La Ligekie. The grey sulphideis powdered finely, and then boiled with an alkalinecarbonate, and the filtered solution allowed to cool.This method is still given in the Prussian Pharma-copoeia. The crystalline grey sulphide is much losssoluble in alkaline carbonates than the amorphousprecipitated red sulphide. Liebig therefore recom-mends that 1 part of finely powdered grey sulphideshould be boiled with 1 part of potassium hydrateand 30 parts of water for one hour, and the filtrateprecipitated while still hot by dilute sulphuric acid.The mixed salts are then divided into 3 parts, eachof which is washed with water, in a separate vessel,by subsidence and decantation, and afterwards col-lected on a filter. The precipitate collected on the