Electron-density studies of metal–metal bonds. I. The deformation density of V₂O₃ at 295 K

The charge-density distribution in V₂O₃ differs from that in Ti₂O₃ mainly with respect to the deformation of the metal atoms. The V atoms show a positive deformation of up to 0.1 e Å^-3 perpendicular to c in a plane containing three nearest V-atom sites across the edges of the surrounding O-atom octahedra, and a negative deformation of up to 0.3 e Å^-3 parallel to c between the nearest V-atom site across the faces of the O-atom octahedra. These observations are in accordance with theoretical band-structure calculations and confirm the existence of an e_π metal-metal bond which is directed across the common edges of the metal-centred O-atom octahedra.