Pressure-induced cation-cation bonding in V2O3

A pressure-induced phase transition, associated with the formation of cation-cation bonding, occurs in V2O3 by combining synchrotron x-ray diffraction in a diamond anvil cell and ab initio evolutionary calculations. The high-pressure phase has a monoclinic structure with a C2/c space group, and it is both energetically and dynamically stable at pressures above 47 GPa to at least 105 GPa. This phase transition can be viewed as a two-dimensional Peierls-like distortion, where the cation-cation dimer chains are connected along the c axis of the monoclinic cell. This finding provides insights into the interplay of electron correlation and lattice distortion in V2O3, and it may also help to understand novel properties of other early transition-metal oxides.