In chemistry a cyanide (from Greek kyanos 'dark blue') is a chemical compound that contains a C=N functional group. 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 cyanide anion -C=N. This anion is extremely poisonous. Soluble salts such as sodium cyanide (NaCN) and potassium cyanide (KCN) 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.