ZnVO3: an ilmenite-type vanadium oxide hosting robust V-V dimers.

Abstract

Ilmenite-type vanadium oxides exhibit a distinctive cation-dimerization behavior. Here, we report a novel ilmenite-type compound, ZnVO3. Polycrystalline ZnVO3 samples are synthesized under conditions of 10 GPa and 1573 K. The obtained sample crystallizes in the triclinic P1̄ space group. Both V-V and Zn-Zn dimers (dimer-like displacement) are present in the structure, arranged in a ladder-like pattern on each honeycomb lattice. Notably, the V-V dimer persists up to 625 K, surpassing the stability of the V-V dimer state in other ilmenite-type vanadium oxides. Magnetic susceptibility measurements corroborate the formation of direct V-V bond in the dimer. The off-centered position of the Zn2+ ion at the octahedral site, driven by Zn-O covalency and its sp3 nature, promotes the Zn-Zn dimer-like displacement. Cooperative distortions between honeycomb layers further reinforce the V-V dimers. This finding offers insights into controlling cation-dimer strength in crystalline compounds via crystal structure distortions.