Magnetic properties of cobalt(II) complexes. Part II. Tetragonally distorted octahedral geometries

Abstract

The theoretical behaviour of principal and average magnetic moments of octahedral cobalt(II) complexes perturbed by spin–orbit coupling and a D_4h symmetry crystal-field distortion is presented. Calculations have been performed using a complete spin–quartet basis. The crystal field is parameterized by the fourth-order quantities Dq and Dt, and by the second-order term Ds.

The magnetic moment of dichlorotetrakis(thiourea)cobalt(II) and dichlorotetra-aquocobalt(II) tetrahydrate as powders and crystals are reported in the temperature range 300–90 K. Attempts to fit these results to the theoretical model do not yield unique values of the parameters and some general observations on the interpretation of cobalt(II) magnetic susceptibilities are made.