Unstable intermediates. Part CXIX. Electron spin resonance studies of radiation effects upon cyanate and thiocyanate ions in alkali-metal halide crystals and in aqueous glasses

Abstract

Irradiated crystalline sodium or potassium cyanate at 77 K had e.s.r. spectra dominated by a quintet assigned to the radical N2CO–, and a triplet assigned to NCO2–. The latter had a 13C hyperfine tensor characteristic of a bent radical as expected, since it is isoelectronic with NO2. In contrast, aqueous glasses containing these salts gave, on irradiation, spectra which have been interpreted in terms of trapped nitrogen atoms and HCNO– radicals. The latter radicals are characterised by an unusually large proton hyperfine coupling, which is interpreted in terms of protonation on carbon.