π-BONDING IN INORGANIC COMPOUNDS: III. A MAGNETOCHEMICAL STUDY OF HEXAHALOOSMATES AND HEXACHLORORHENATE

Abstract

The anomalously small magnetic moments of osmium(IV) and rhenium(IV) in their hexahalo complexes are investigated by measurement of the magnetic susceptibilities of the mixed crystal systems, K₂OsCl₆/K₂PtCl₆, K₂OsBr₆/K₂PtBr₆, and K₂ReCl₆/K₂PtCl₆. It is shown that only at high dilution is the magnetic behavior of the systems that which is expected from theory; therefore, extensive superexchange through the overlap of d-orbitals on the central atom and orbitals on the ligands takes place in the pure substances and in the concentrated systems. Determination of the spin–orbit coupling constant for OsCl₆²⁻ provides a value in agreement with estimates based on spectra.