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of commerce, consists of " steel-gray masses of a metallic lustre and a striated, crystalline fracture," which are easily pulverized and fused.

This article is likely to contain arsenic, which is almost completely separated by macerating the finely-divided substance with about one-half its weight of 10-per-cent. ammonium hydrate solution, which dissolves the impurity from out the antimony compound, and leaves the Antimonii Sulphidum Purificatum, U. S. P.

When this purified sulphide is boiled with about twelve times its weight of 5-per-cent. sodium hydrate solution for two hours, the following reaction takes place :

2SbSg4NaOH = NaSbO, + 3NaSbSg + 2H2O.

If the solution thus obtained is strained, and while still hot decomposed by excess of diluted sulphuric acid, an amorphous, reddish-brown powder is thrown down :

NaSbO3NaSbS2+ 2H2SO4 = 2SbgSg + 2H2O + 2NagSO4.

When collected, washed, and dried at a slightly elevated temperature, the powder is found to be odorless and tasteless.

It is known in medicine as sulphurated antimony, Antimonium Sulphuratum, U. S. P., or kermes mineral, and formerly was much used as a remedy.

A very small amount of trioxide contaminates the above product. Artificial trisulphides may be produced by melting antimony with sulphur, or by precipitating a solution of an antimony salt with hydrogen sulphide. The amorphous, orange, hydrated product of the last method may be changed to the crystalline black trisulphide by heat.

Uses. -Crystalline antimony trisulphide is used not only for the preparation of the other antimony compounds, but also in fireworks, such as the blue or Bengal lights used at sea, and for the preparation, especially in Sweden, of the heads of lucifermatches, as well as for the composition of percussion-caps. The amorphous variety is largely used as a means for vulcanizing caoutchouc, to which it imparts a reddish-brown color.

Antimony Pentasulphide, Sb,S,, sometimes called golden sulphuret of antimony, cannot be prepared by the direct combination of its constituent elements, but can be obtained by boiling the trisulphide and sulphur with fixed alkali hydrate or carbonate and subsequent neutralization of the solution by acid.

It may also be had as a fine yellowish-red powder by acidifying a solution of a crystallized sulphantimonate. The resulting precipitate, when carefully dried in the dark, is easily soluble in aqueous solutions of alkali hydrates and sulphides.

Antimony Cinnabar is an oxysulphide obtained by the action of a solution of sodium thiosulphate upon antimony trichloride. It is used in painting. Crocus and glass of antimony consist of varying proportions of oxide and oxysulphide, and are gotten by partly roasting the ore in air, or by incomplete oxidation by deflagration with potassium nitrate.

Both tri- and pentasulphide of antimony are capable of combining with the alkali sulphides to form sulphantimonites and sulphantimonates respectively. Acids corresponding to these salts are not known in the free state, but the salts themselves have been studied. The alkali sulphantimonites, which are brown or black, are produced by fusing the alkali hydrate or carbonate with antimony trisulphide, or by dissolving the latter in a solution of an alkali hydrate whereby both sulphantimonite and antimonite are formed. The solutions are not stable, but are decomposed by acids with precipitation of the amorphous trisulphide.

This class of compounds is sometimes called liver of antimony. Sodium Sulphantimonate, Na,SbS4 + 9H2O, or Schlippe's Salt, is the best representative of the higher class of these sulpho-salts. It is prepared by heating a mixture of 8 parts of anhydrous sodium sulphate and 3 parts of charcoal to fusion in a crucible, and adding thereto, under continued heat, 6 parts of finelypowdered antimony trisulphide previously mixed with 11⁄2 parts of sulphur, maintaining the fusion until the color of the trisulphide has disappeared. The cooled mass is extracted with

water.

The same compound may also be made in the wet way by boiling the trisulphide and sulphur with milk of lime and sodium carbonate.

In both cases the filtered solutions are evaporated and allowed to crystallize. The salt is obtained in fine, transparent tetrahedra which are soluble in three parts of water. When the solu

tion is acidified antimony pentasulphide is thrown down.

Schlippe's salt is used in photography.

The sulphantimonates of the heavy metals are insoluble in water, and can be formed by double decomposition of the proper substances. They include many of the ores of antimony.

Antimony Triselenide, SbSeg, and pentaselenide, SbSe, antimony tritelluride, Sb,Teg, antimony phosphide, SbP, and antimony arsenide, SbAs, are known; the last as an ore of the metal, the others as products of the union of the elements.

BISMUTH.

Atomic Weight, 208.9.

Valence, III and V.

Symbol, Bi. History. Probably bismuth was first distinctly recognized in 1450 by Basil Valentine, who attempted to classify it with other metals. In the following century, Paracelsus classed it among the semi-metals, but it was afterwards proposed as a true metal by Agricola. Although clearly described by the last author, bismuth was subsequently confounded with other metals, especially with antimony and zinc, until 1739, when Pott contributed to the more accurate knowledge of the element. Its reactions were investigated by Bergman.

It

The name is from the German, Wismuth. Occurrence.-The sources of bismuth are not numerous. forms an exception to most metals by occurring chiefly in the free state, sometimes nearly pure. Both the metal and its ores are generally disseminated through rock. The most important works for its production are at Schneeberg, in Saxony, where the ore occurs associated with cobalt minerals. The mines of England, France, Hungary, and Scandinavia also afford it.

The Magnesium Works at Patricroft, in England, work up considerable quantities of imported bismuth ore, which in recent years has been brought into commerce from California, Colorado, Utah, Texas, Mexico, South America, and Australia.

Besides as native metal, bismuth is found as bismuth-ochre, BigO, less frequently as bismuthite, BigS,, and occasionally associated with many of the heavy metals and as carbonate and sili

cate.

Preparation. The process of obtaining the metal usually applied in the past consisted in heating the ore in iron tubes inclined in such a way that the easily fusible metal could run off into proper receptacles. This method extracted only that part of the bismuth which existed in the free state.

At present the ores are roasted to expel most of the sulphur, and then fused in small furnaces with iron to remove sulphur, charcoal to reduce the ore, and slag to facilitate the operation. The molten mass so obtained is allowed to stand, when a separation into two layers occurs, the lower being nearly pure bismuth.

When the upper layer, which consists of the cobalt-speiss, iron, and various constituents of the ore, has hardened, the still liquid bismuth is transferred to ingot moulds.

When the metal occurs in ores of lead and silver, it is extracted from the slag, in which it collects in quantity from 5 to 20 per cent., by cold hydrochloric acid, and subsequently precipitated as basic chloride by water, or as metal by means of iron. In all such cases it is finally reduced by soda-ash and coal.

Bismuth is generally sent into commerce in hemispherical masses which weigh from 10 to 12 kilogrammes.

Properties.-Bismuth is isomorphous with arsenic and antimony. It is generally met with in brilliant, grayish-white or iridescent masses having a crystalline lamellate texture, on account of which, although hard, the metal can be readily reduced to a powder. The roseate tinge usually present is said to arise from a slight superficial oxidation. When melted and allowed to cool the metal expands quite notably.

Bismuth is the most diamagnetic of all known bodies, a good conductor of electricity, but a poor conductor of heat. It combines directly with the halogens and sulphur, and has a specific gravity of 9.83.

It melts at 264°, and at a white heat (about 1100°) may be distilled in hydrogen. It is permanent in air at ordinary temperatures, but when heated before the blowpipe on charcoal yields bismuth trioxide as a brown incrustation, which becomes yellow on cooling.

Hydrochloric acid does not dissolve the metal, but it is soluble in nitrohydrochloric acid and in hot concentrated sulphuric acid. Nitric acid also dissolves bismuth. When an acid of specific gravity 1.2 is employed, the presence of arsenic may be detected. by the white deposit of bismuth arsenate, which fails to dissolve.

Although commercial bismuth is likely to contain arsenic and other impurities, still it is usually found in the market of such purity that it can be used for preparing the compounds, particularly the basic nitrate, and some authorities state that the presence of as much as .5 per cent. of arsenic does not disqualify the metal for that purpose.

To free it of arsenic the powdered metal is mixed with 5 or 6 per cent. of potassium or sodium nitrate and fused in a Hessian crucible by means of a charcoal fire. After the half-cooled mass has been heated for a minute with 5 per cent. fixed alkali hydrate

solution, the metal is collected and thoroughly washed with

water.

Other processes of purification consist in fusing the bismuth with potassium bitartrate in a carbon crucible, or with potassium carbonate, charcoal, and soap.

Uses. Large quantities of bismuth are used for preparing its compounds, especially the subnitrate, and for alloys.

Alloys. The presence of bismuth materially lowers the fusing point of alloys, and on that account, as also because of its property of expanding when fused and allowed to cool, alloys containing it are specially adapted for type-metal, for taking the impression of wood-cuts, and for stereotyping. For the last two purposes the so-called fusible metals are employed. Of these, Wood's metal, consisting of 15 parts of bismuth, 8 parts of lead, 4 parts of zinc, and 3 parts of cadmium, melts at 68°, while Rose's Metal, containing 1 part of tin, 1 part of lead, and 2 parts of bismuth, has a fusing point of 94°. Many other uses are made of its alloys.

BISMUTH AND THE HALOGENS.

Bismuth Dichloride, BiCl, or BigCl4, is formed when a slow current of chlorine is passed over the fused metal, or when the latter is heated with calomel to 250°. It is a black, crystalline mass, readily decomposed.

Bismuth Trichloride, BiCl,, is obtained when bismuth is heated in dry chlorine, or by distilling 1 part of finely-divided metal with 2 parts of mercuric chloride, and also by dissolving bismuth in nitro-hydrochloric acid, evaporating the solution, and distilling the residue.

It is a white, deliquescent, fusible, and volatile mass, known as bismuth butter. It is soluble in alcohol, and by the addition of much water is changed to insoluble, white, crystalline basic bismuth chloride, known as pearl white.

Bismuth trichloride forms double chlorides with the alkali metals.

Bismuth Tri-iodide, Bilg, results from the direct combination of its constituent elements when the same are fused together, but it may be more conveniently prepared by precipitation of a solution of bismuth nitrate by potassium iodide. So obtained it is a brown-red powder.

Bismuth Oxyiodide, BiOI.-This compound is produced by boiling for half an hour a solution of 40 parts of bismuth subnitrate in 3 parts of nitric acid and 400 parts of water with 24 parts of potassium iodide dissolved in 200 parts of water.

The very fine crystalline precipitate is collected, washed, and dried below 100°.

Uses. This substance has been proposed in late years as a substitute for iodoform.

BISMUTH AND OXYGEN.

The compounds of bismuth form two classes: those in which the metal, as such, is in combination with the negative atom or group of atoms, and those wherein the univalent group, BiO, known as bismuthyl, occupies the same position.

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