A<unk>  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<unk> s, the<unk>  group is present as the anion<unk> −. Soluble salts such as sodium<unk>  and potassium<unk>  are highly toxic. Hydrocyanic acid, also known as hydrogen<unk> , or HCN, is a highly volatile liquid that is produced on a large scale industrially. It is obtained by acidification of<unk>  salts. Organic<unk> s are usually called nitriles. In nitriles, the<unk>  group is linked by a covalent bond to carbon. For example, in acetonitrile, the<unk>  group is bonded to methyl (CH3). Although nitriles generally do not release<unk>  ions, the cyanohydrins do and are thus rather toxic. The word<unk>  is derived from the Greek kyanos, meaning dark blue; the color of Prussian blue used to prepare the compound.
Cyanide
Lewisite
Bromide
Hydrogen fluoride
Carbonated water
Carbon monoxide
Isothiocyanate
Metaldehyde