An inorganic cyanide compound is any chemical compound that contains a monovalent combining group -CN. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Most of the cyanides are highly toxic. When cyanide combines with chemicals from the metal groups, it forms simple salts. Calcium cyanide, potassium cyanide, and sodium cyanide are all examples of simple cyanide salts. They are all white solids, and soluble in water. Cyanide anion, owing to its high nucleophilicity, can be introduced as nitriles in organic compounds through replacement of halides or other leaving groups. Cyanides can be used to lengthen a carbon chain by one step.
Cyanide compounds are mainly used in electroplating, metallurgy, the production of orgainc chemicals (acrylonitrile, methyl methacrylate, adiponitrile, etc.), photographic development, the extraction of gold and silver from ores, tanning leather and in the making of plastics and fibres. Metals have high affinity to the cyanide anion due to its compactness, negative charge and ability to form pi-bonding. Many coordination compounds contain cyanide as ligand, for example, Prussian blue, hexacyanides, tetracyanides and dicyanides.