Dithiocyanic Acid, (HCNS)₂

Dithiocyanic Acid, (HCNS)₂, is obtained by decomposing its potassium salt with sulphuric acid. The potassium salt is formed when perthiocyanic acid (see below) is treated with a cold aqueous solution of potassium hydroxide. It is a dark yellow powder, slightly soluble in cold water, more soluble in hot water; it is soluble in alcohol and in ammonia. Aqueous and alcoholic solutions made in the cold do not colour ferric salts.