Magnetic exchange interactions in tetrabromocuprate compounds

Magnetic and structural data for 28 compounds containing the tetrabromocuprate ion are presented. The parameters which affect the strength and sign of the magnetic superexchange interaction via non-bonding contacts between bromide ions are described and a system for describing the topology of the interaction between tetrahedra is proposed. Analysis of the data suggests that the primary factors affecting the magnetic exchange are the Br⋯⋯Br distance, the Cu–Br⋯⋯Br angle and the Cu–Br⋯⋯Br–Cu dihedral angle.