Uses, &c. Bismuth enters into the composition of STEREOTYPE-METAL, SOLDER, PEWTER, FUSIBLE METALS, and several other alloys. Added to other metals it renders them more fusible. An alloy of tin, nickel, bismuth, and silver is said to hinder iron from rusting. A mixture of bismuth, lead, and tin is much employed for taking impressions from dies, forming moulds, and for other purposes.
Bismuth salts are usually insoluble, or decomposed by any quantity of water into free acid and a basic salt. They are nearly all colourless, and, except the chloride, more volatile. They are easily recognised by the following reactions:—
Their saturated or concentrated solutions giving a white precipitate on dilution with water:—Sulphuretted hydrogen blackens them, or gives a black precipitate:—The nitric solution is unaffected by the addition of sulphuric acid:—Chromate of potassium gives a yellow precipitate, which differs from that from lead, by being soluble in nitric acid, and insoluble in potassa.
Von Kobbell takes a mixture of potassium iodide and flowers of sulphur in equal proportions, and heats the whole on charcoal before the blowpipe; the production of bright scarlet, very volatile bismuth iodide ensues, even when only traces of bismuth are present.
For a method of volumetrically estimating bismuth, consult a paper by Mr Pattison Muir, in the ‘Journal of the Chemical Society,’ April, 1876.
Bismuth, Car′bonate. (Ph. B.) Mix nitric acid, four fluid ounces, with three fluid ounces of distilled water, and add in successive portions purified bismuth, in small pieces, two ounces. When effervescence has ceased apply for ten minutes a heat approaching ebullition; then decant the solution from any insoluble matter. Evaporate to two fluid ounces, and add this in small quantities at a time to a cold filtered solution of six ounces of carbonate of ammonia, in two pints of distilled water, constantly stirring. Collect precipitate on a calico filter; wash till washings pass tasteless. Remove water by slight pressure of the hands, and dry at a heat not exceeding 150°.—Dose, 5 to 20 grains.
Bismuth, Chlorides of:
Basic Chlo′′ride. Bi3Cl8. Syn. Subchlo′′ride of bismuth, Pearl′-powder; Bismu′thi subchlori′dum, L. Prep. A dilute solution of hydrochloric acid is dropped into another of bismuth (prepared by dissolving that metal in nitric acid); and the resulting
precipitate, after being well washed in pure water, is dried in the shade.—Prop., Uses, &c. Similar to those of the subnitrate.
Chlo′′ride. BiCl3. Syn. Terchlo′′ride of bismuth. Prep. A mixture of corrosive sublimate, 2 parts; bismuth, 1 part; (both in powder) is exposed to heat until all the ‘mercury’ present is expelled, after which it is at once put into bottles. A greyish-white, granular substance.