ChemInform Abstract: SEMI‐EMPIRICAL UHF‐MO STUDIES OF THE SPIN DISTRIBUTION AND THE BONDING CHARACTER OF IRON‐GROUP FLUORIDES AND SOME OTHER SIMILAR TRANSITION METAL HALIDES

Abstract

CNDO- and INDO-type UHF-MO calculations are carried out on MF6n− (M=V(II), Cr(III), Mn(II), Fe(III), Ni(II)), NiCl64−, MnCl64−, MnCl42−, MnBr64−, and CuCl42−. The calculated spin fractions on the ligand orbitals agree well with the experimental values, with a few exceptions. Spin transfers to ligands are mainly attributed to the spin delocalization (SD) mechanism, except those to the 2s and 2pσ, orbitals of the F ligand in CrF63− and VF64−, in which spin transfer to those orbitals results from the spin polarization (SP) mechanism. Unpaired electrons are also transferred into the 4s and 4p orbitals of the central metal ion by the SP mechanism. The spin transfers to the ligand due to both the SD and SP mechanisms increase in the order of F<Cl<Br in MnX64− and NiX64−. The following characterisities of metal-halogen bonds are established; (1) the covalent interaction between the metal d-orbital and the fluorine atom increases in the order Ni(II)<Mn(II)∼ Fe(III)<Cr(III)∼V(II) in MF6n−, and (2) in metal-halogen...