AbstractThe interaction of iodine cyanide and cyanide in aqueous solution has been reinvestigated and it has been confirmed that a complex cyanide ion, the dicyanoiodate(I) ion [I(CN)2]−is formed. This ion has been isolated in the solid state for the first time, as its tetraphenylarsonium, tetraphenylphosphonium and caesium salts. Infrared and Raman spectroscopic studies of these salts are reported. These spectra are fully consistent with a linear centrosymmetric (D∞h) structure for the [I(CN)2]−ion. Assignments are made for six of the seven fundamentals of the [I(CN)2]−ion in the caesi