Cyanate

The cyanate ion is an anion with the chemical formula OCN⁻. It is a resonance of three forms: [O⁻−C≡N] (61%) ↔ [O=C=N⁻] (30%) ↔ [O⁺≡C−N²⁻] (4%).

Cyanate is the derived anion of isocyanic acid, H−N=C=O, and its lesser tautomer cyanic acid (a.k.a. cyanol), H−O−C≡N.

Any salt containing the ion, such as ammonium cyanate, is called a cyanate.

The cyanate ion is an isomer of the much-less-stable fulminate anion, CNO⁻ or [C⁻≡N⁺−O⁻].^[1]

The cyanate ion is an ambidentate ligand, forming complexes with a metal ion in which either the nitrogen or oxygen atom may be the electron-pair donor. It can also act as a bridging ligand.

Compounds that contain the cyanate functional group, −O−C≡N, are known as cyanates or cyanate esters. The cyanate functional group is distinct from the isocyanate functional group, −N=C=O; the fulminate functional group, −O−N⁺≡C⁻; and the nitrile oxide functional group, −CNO or −C≡N⁺−O⁻.