AURI PERCHLORIDUM - PERCHLORIDE OF GOLD - "POTABLE GOLD" OF ALCHEMISTS, AuCl3, = 303 (NOT OFFICINAL).

Preparation

By dissolving the metal in nitro-hydrochloric acid, with gentle heat. On evaporating, yellow crystals of the salt are left in combination with some free acid (AuCl32HClH1O). After the acid has been driven off, the color of the crystals is red, and they have the composition AuCl3. This salt is used in photography and in analytical chemistry, and a solution of it, freed from excess of acid, is placed in the appendix to the Pharmacopoeia as a test solution for atropia.

AURI PEROXIDUM - PEROXIDE OF GOLD - "AURIC ACID," Au2O3, = 441.2 (NOT OFFICINAL).

Preparation

By treating the perchloride with magnesia, washing the precipitate, and digesting in dilute nitric acid, which removes the magnesia. The peroxide forms, when dried, a brown powder, insoluble in water, and decomposed by exposure to light.

Auri Et Sodii Chloridum - Chloride Of Gold And Sodium, AuCl3NaC12H1O (NOT OFFICINAL).

Preparation

By mixing in solution about 5 parts of chloride of gold and 1 part of chloride of sodium, and evaporating to crystallization; long, four-sided prisms are left, of deep yellow color. This combination, which is deliquescent and soluble in water, is the form most commonly prescribed; it has a nauseous taste, and should not therefore be given in solution.

AURI IODIDUM - IODIDE OF GOLD, AuI3 (NOT OFFICINAL).

Preparation

By mixing solutions of iodide of potassium and perchloride of gold. The precipitate, when collected, washed, and dried, forms a greenish yellow powder, insoluble in cold, but slightly soluble in boiling water.