Cyanide
Cyanide, a compound formed by the union of a metal or hydrogen with the poisonous gas cyanogen. Hydrogen cyanide, also called hydrocyanic acid or prussic acid, is a deadly poison used to kill rats and insects. Sodium and potassium cyanides are used in the cyanide process of separating gold and silver from their ores.
Hydrogen cyanide is also used in the gas chamber method of execution. Pellets of cyanide are dropped or lowered into a container of sulfuric acid to release hydrogen cyanide in gaseous form. The gas brings death within five minutes.
The cyanide radical is CN-. Hydrocyanic acid is HCN; sodium cyanide, NaCN; potassium cyanide, KCN.