Zinc, Cy′anide of. ZnCy2. Syn. Cyanuret of zinc; Zinci cyanidum, Zinci cyanuretum, L. Prep. (P. Cod.) Add a solution of cyanide of potassium to another of pure sulphate of zinc; wash, and dry the precipitate.—Dose, 1⁄8 to 1 gr., twice a day; in epilepsy, hysteria, and other nervous affections, heartburn, worms, &c.; and as a substitute for hydro-cyanic acid.
Zinc, Ferrocy′anide of. Zn2FeCy6. Syn. Zinci ferrocyanidum, L. Prep. By adding a hot solution of ferrocyanide of potassium to a hot and strong solution of pure sulphate of zinc, and washing, and drying the precipitate. White.—Dose, 1 to 4 gr.; in the same cases as the last.
Zinc, I′odide of. ZnI2. Syn. Hydriodate of zinc†; Zinci iodidum, Zinci hydriodas, L. Prep. 1. (Duflos.) Iodine, 2 parts; granulated zinc, 1 part; water, 4 parts; proceed as for ferrous iodide, only employing a glass or porcelain vessel.
2. (Magendie.) Iodine, 17 parts; zinc (in powder), 20 parts; mix, and sublime in a matrass.
Prop., &c. Deliquescent. Chiefly used externally; 15 gr. to water, 6 fl. oz., as a collyrium in scrofulous inflammation of the eye (Poulet); 1 dr. to lard, 1 oz., as a powerful resolvent in scrofulous and other glandular swellings, rubbed on the part twice a day. (Ure.)
Zinc, Lac′tate of. Zn(C3H5O2)2. Syn. Zinci lactas, L. Prepared from zinc in the same way as ferrous lactate is from iron.
Zinc, Ox′ide of. Syn. Protoxide of zinc; Zinci oxydum (B. P., Ph. L., E., & D.), L. Prep. 1. (Ph. L.) Sulphate of zinc (pure), 1 lb.; carbonate of ammonium, 61⁄2 oz.; dissolve each separately in 6 quarts of water, filter, mix the solutions, well wash the precipitate with water, and calcine it for 2 hours in a strong fire. The Ph. E. is nearly similar.
2. (Ph. D., B. P.) Place carbonate of zinc in a covered clay crucible, and expose it to a very low red heat, until a portion taken from the centre of the mass ceases to effervesce on being dropped into dilute sulphuric acid.
Prop., &c. A white, tasteless powder; insoluble in water; freely soluble in acids, the solution yielding colourless and easily crystallisable salts; strongly basic.
Uses, &c. It is tonic and antispasmodic, and has been advantageously used in chorea, epilepsy, and other nervous and spasmodic affections.—Dose, 1 to 6 gr., twice a day. It is also used as a dusting powder, and to make an ointment. It has been proposed as a substitute for white lead in painting, than which it covers better, but dries slower, and hence requires the addition of dried white vitriol. This oxide is the only compound which zinc forms with oxygen.