[905] Proceed. Brit. Pharm. Conf., 1867, p. 10.
[906] Journ. Pharm. et Chim., le Série, 1858, vol. viij. p. 399.
Ointment of Ammoniated Mercury (Unguentum hydrargyri ammoniati).—1 part of ammoniated mercury mixed with 9 parts of simple ointment.
Red Iodide of Mercury (Hydrargyrum iodidum rubrum, HgI2).—A crystalline powder of a scarlet colour, becoming yellow on gentle heating. It is very insoluble in water, one part requiring from 6000 to 7000 parts; soluble in 130 parts of cold, 150 of hot alcohol; and dissolving freely in ether, or in aqueous solution of iodide of potassium.
Ointment of Red Iodide of Mercury (Unguentum hydrargyri iodidi rubri).—16 grains of the substance mixed with an ounce of simple ointment.
Green Iodide of Mercury (Hydrargyri iodidum viride, HgI).—A dingy, greenish-yellow powder, darkening on exposure to light, and easily decomposed into the red iodide.
Red Oxide of Mercury (Hydrargyri oxidum rubrum), HgO = 216; Hg, 92·12 per cent.; specific gravity, 11 to 11·3; small, red, shining, crystalline scales, very insoluble in water, requiring about 20,000 parts; entirely soluble in hydrochloric acid. By a heat below redness it may be volatilised, and at the same time decomposed into mercury and oxygen. Its principal impurity is nitric acid, readily detected by the usual tests, or by heating in a test-tube, when, if nitric acid is present, orange vapours will be evolved. Fixed red powders (such as brick-dust and minium) are detected by being left as a residue, after the application of heat sufficient to volatilise the mercury. An ointment (strength 1 : 8) is officinal.
Sulphate of Mercury.—A white crystalline powder, decomposed by water into the very insoluble basic salt of mercury, known as Turbith mineral, HgSO42HgO.
Turbith, or Turpeth, Mineral is contained in the French pharmacopœia, HgSO42HgO; Hg, 82·4 per cent.; specific gravity, 8·319. It requires for solution 2000 parts of cold, and 600 of boiling water; but dissolves with tolerable ease in hydrochloric acid.