Scientific Background
A cyanide is a chemical compound that contains the group C≡N. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. In inorganic cyanides, the cyanide group is present as the anion CN−. For the salts such as sodium cyanide and potassium cyanide, these compounds are highly toxic. Hydrocyanic acid, also known as hydrogen cyanide, or HCN, is a highly volatile liquid that is produced on a large scale industrially. It is obtained by acidification of cyanide salts. Organic cyanides are usually called nitriles. In nitriles, the CN group is linked by a covalent bond to carbon. For example, in acetonitrile, the cyanide group is bonded to methyl (CH3). Because they do not release cyanide ions, nitriles are generally far less toxic than cyanide salts. Some nitriles, which occur naturally as cyanohydrins, release hydrogen cyanide.