Thallous cyanide, TlCN

Thallous cyanide, TlCN, may be obtained by adding thallous hydroxide to prussic acid, or by mixing concentrated solutions of thallous nitrate and potassium cyanide, when thallous cyanide is precipitated. It is best prepared from barium cyanide and thallous sulphate. It crystallises from water, in which it is not very soluble, in glittering plates. When heated it decrepitates, melts, and decomposes.

One hundred grams of water dissolve 8.67 at 0°, 15.17 at 14°, and 29.57 grams at 31°, of thallous cyanide. The solution reacts alkaline and smells of prussic acid. The cyanide is soluble in alcohol, but very sparingly soluble

in a mixture of alcohol and ether. It dissolves in aqueous potassium cyanide, forming soluble potassium thallium cyanide, and forms numerous double and complex cyanides with other cyanides.