ESR Studies and Covalent Bonding of Cyanide and Fluoride Complexes of Transition Metals

ESR spectra of [Cr(CN)6]3— in dilute solid solution in K3Co(CN)6 single crystals have been obtained and the hyperfine splitting constants measured. These have been interpreted to provide values of the isotropic and anisotropic components As=—9.85±0.1 G and Ap=+0.65±0.2 G. The sigma and pi-bond character of the metal—ligand bonds for [Cr(CN)6]3— and [CrF6]3— have been computed using molecular orbital theory and compared with the corresponding values for some other cyanide and fluoride complexes.