Some electron spin resonance and infra-red studies of irradiated cyanides.
thesisposted on 19.11.2015, 08:47 by K. D. J. (Keith David John) Root
This thesis reports some electron spin resonance and other spectroscopic studies of radiation damage in ionic cyanides, and in alkali halides doped with simple and complex cyanide ions. A correlation of electron spin resonance data for F-centres has been obtained which relates the isotropic hyperfine coupling, from the first shell of cations surrounding the F-centre, to the lattice size and the atomic radius of the cations. This correlation has been used to identify the electron spin resonance spectrum of the F-centre in ?-irradiated sodium cyanide. The electron spin resonance spectrum of the Vk-centre in ?-irradiated sodium and potassium cyanide is reported. The Vk-centre (The cyanogen negative ion (CN)-2) has also been prepared in ?-irradiated potassium chloride doped with cyanide ions. A single crystal study of this radical has been performed and the structure determined and compared with the HCN- and H2CN radicals which were also formed on irradiation of the doped potassium chloride. In all three radicals the unpaired electron is in the plane of the molecule and there is a considerable delocalization of the spin density. The effect of both ?-irradiation and ultra-violet irradiation on ferrous and ruthenium hexacyanide incorporated into alkali halide lattices has been examined by electron spin resonance, infra-red and electronic spectroscopy. The new spectral bands have been interpreted in terms of the formation of iron and ruthenium complexes in oxidation state (I). The electron spin resonance spectra indicate a novel distortion of the d7 transition metal complex which produces a unique ligand. Possible interpretations of the electron spin resonance spectra are discussed. Finally an infra-red study of ?-irradiated alkali halides doped with simple cyanide ions shows that the major product on irradiation is the cyanate ion. Likely mechanisms for the formation of this ion and the other species reported in this thesis are considered.