ELECTRIC-FIELD GRADIENTS AND MAGNETIC HYPERFINE PARAMETERS OF SQUARE-PYRAMIDAL [M(CN)(5)](3-) (M=CO, RH, AND IR) COMPLEXES

Density functional self-consistent spin-polarized calculations with th e discrete variational method were performed to obtain the electronic structure of the paramagnetic complexes [Co(CN)(5)](3-), [Rh(CN)(5)](3 -), and [Ir(CN)(5)](3-) of square-pyramidal geometry. AU electrons wer e kept in the variational space. Electric-field gradients and magnetic hyperfine parameters at the metal site were computed with the molecul ar charge and spin densities obtained and compared with experimental v alues derived by electron paramagnetic resonance. It was found that th e Fermi interaction is critically dependent on the angle between the a xial and equatorial CN ligands. (c) 1995 John Wiley & Sons, Inc.