e. (M. Gay-Lussac.) If the chloride, dry it, and throw it, in successive portions, into twice its weight of carbonate of potassa fused in a red-hot Hessian crucible; effervescence
ensues, and the pure silver subsides to the bottom.—If a “soluble salt,” as the nitrate, acidulate the solution, and precipitate it by means of a polished plate of copper; the silver is then obtained in the form of powder. The products of the above processes, when the latter are carefully conducted, are chemically pure silver.
Silver, Acetate of. Syn. Argenti acetas, L. Prep. By adding a solution of acetate of potassa to a like solution of nitrate of silver, washing the precipitate with cold water, redissolving it in a little hot water, and setting the solution aside to crystallise. Small colourless needles.
Silver, Ammoniuret of. See Fulminating silver (Berthollet’s, Nos. 1 and 2, page 768).
Silver, Ammonio-chloride of. Syn. Argentochloride of ammonia; Argenti ammonio-chloridum, L. Prep. Add, gradually, chloride of silver (recently precipitated and well washed) to concentrated liquor of ammonia, as long as it is dissolved on agitation, applying a gentle heat towards the end; then heat the solution to the boiling-point, concentrate a little, and allow it to cool very slowly; collect the crystals which form, dry them by pressure (with care) between folds of bibulous paper, and at once preserve them from the light and air.—Dose, 1⁄16 to 1⁄8 gr.
Silver, Ben′zoate of. AgC7H5O2. Thin transparent plates, which are blackened by exposure to the light. See Benzoate.
Silver, Bro′mide of. AgBr. Resembles the chloride.
Silver, Car′bonate of. Ag2CO3. Syn. Argenti carbonas, L. A white insoluble powder, obtained by precipitating a cold solution of nitrate of silver with another of carbonate of sodium. It is decomposed by heat.
Silver, Chlo′′ride of. AgCl. Syn. Argentic chloride. Prep. Precipitate a solution of nitrate of silver by dilute hydrochloric acid or a solution of common salt; wash the precipitate, and dry it in the shade.—Dose, 1⁄4 to 3 gr., thrice daily; in epilepsy, chronic dysentery, cholera, diarrhœa, &c. Dr Perry regards it as preferable to the nitrate. When fused, chloride of silver forms horn silver, the ‘luna cornea’ of the older writers.
Silver, Cy′anide of. AgCN. Syn. Argentic cyanide, Hydrocyanate of silver. Prep. Add dilute hydrocyanic acid to a solution of nitrate of silver, as long as a precipitate falls; wash this with distilled water, and dry it.