hydrate and ammonia turn it dark grey or black.
Potassium iodide gives a greenish-yellow precipitate, soluble in ether, and subliming in red crystals when heated.
Mercurous Acetate. Hg(C2H3O2). Syn. Acetate of mercury, Subacetate. Prep. (P. Cod.) Dissolve mercurous nitrate, 1 part, in water (slightly acidulated with nitric acid), 4 parts, and precipitate the liquid with a solution of sodium acetate, gradually added, until in slight excess; carefully wash the precipitate with cold water, and dry it in the shade.
Prop., &c. Small, white, micaceous, flexible scales; insoluble in alcohol; soluble in about 300 parts of water; blackened by light; and carbonised by a strong heat. It has been said to be one of the mildest of the mercurials; but this cannot be the case, as it occasionally acts with great violence on both the stomach and bowels, producing much pain and prostration.—Dose, 1⁄6 to 1 gr., night and morning, gradually increased.
Mercurous Bromide. HgBr. Syn. Subbromide of mercury; Hydrargyrum bromidum, L. Prep. (Magendie.) By precipitating a solution of mercurous nitrate by another of potassium bromide. It closely resembles calomel in both its appearance and properties.—Dose, 1 to 5 gr.
Mercurous Chloride. HgCl or Hg2Cl2. Syn. Calomel, Subchloride of mercury, Mercury chloride; Hydrargyri subchloridum (B. P.), Hydrargyri chloridum (Ph. L.), H. c. mite (Ph. U. S.), Calomelas (Ph. E. & D.), L. This substance is one of the best known, and probably the most valuable, of all the mercurials.
Prep. 1. (Ph. L.) Mercury, 2 lbs.; sulphuric acid, 211⁄2 fl. oz.; mix, boil to dryness (in a cast-iron vessel), and when the resulting mass has cooled, add of mercury, 2 lbs., and triturate the ingredients in an earthenware mortar until they are well mixed; then add of sodium chloride, 11⁄2 lb., and again triturate until the globules are no longer visible; next sublime the mixture, reduce the sublimate to the finest possible powder, diligently wash it with boiling distilled water, and dry it.—Prod. 117 or 118% of the weight of mercury employed.
2. (Ph. F.) Mercury, 4 oz., is dissolved in a mixture of sulphuric acid, 2 fl. oz. 3 fl. dr., and nitric acid, 1⁄2 fl. oz., by the aid of heat; when cold, mercury, 4 oz., is added, and the remainder of the process is conducted as before.
3. (Calomelas sublimatum.—Ph. D.) Sulphate of mercury, 10 parts; mercury, 7 parts; dry sodium chloride, 5 parts; triturate, &c., as before, and afterwards resublime it into a large chamber or receiver.
4. (Ph. B.) Same as Dublin.