V–V Dimerization and Magnetic State of Cobalt Ions in Ilmenite-Type CoVO3

The nature of chemical bonds determines the electronic and magnetic properties of compounds. A metal–metal bonding (V–V dimer) and its effect on the magnetism of ilmenite-type CoVO3 were studied. Polycrystalline CoVO3 samples were synthesized using a high-pressure synthesis method. Crystal structure refinement revealed that V–V dimers exist at temperatures below 550 K in the vanadium layers. Co2+ in CoVO3 exhibits an S = 3/2 state, whereas a J eff = 1/2 state was reported in ilmenite-type CoTiO3. The existence of V–V dimers reduces the structural symmetry (from R 3 to P 1), which can change the magnetic ground state.