Ti2O3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra are not tilted. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ti(2) and four equivalent Ti(1) atoms to form OTi6 octahedra that share corners with four equivalent O(3)Ti5 square pyramids, edges with two equivalent O(1)Ti6 octahedra, and edges with six equivalent O(3)Ti5 square pyramids. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ti(1) and two equivalent Ti(2) atoms. In the third O site, O(3) is bonded to two equivalent Ti(2) and three equivalent Ti(1) atoms to form OTi5 square pyramids that share corners with two equivalent O(1)Ti6 octahedra, edges with three equivalent O(1)Ti6 octahedra, and edges with four equivalent O(3)Ti5 square pyramids. The corner-sharing octahedral tilt angles are 4°. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Ti(2) atoms.
Ti2O3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra are not tilted. The Ti(1)-O(2) bond length is 2.00 Å. Both Ti(1)-O(1) bond lengths are 2.13 Å. There are two shorter (2.09 Å) and one longer (2.19 Å) Ti(1)-O(3) bond length. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. The Ti(2)-O(1) bond length is 2.51 Å. The Ti(2)-O(4) bond length is 1.81 Å. Both Ti(2)-O(2) bond lengths are 1.96 Å. Both Ti(2)-O(3) bond lengths are 2.07 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ti(2) and four equivalent Ti(1) atoms to form OTi6 octahedra that share corners with four equivalent O(3)Ti5 square pyramids, edges with two equivalent O(1)Ti6 octahedra, and edges with six equivalent O(3)Ti5 square pyramids. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ti(1) and two equivalent Ti(2) atoms. In the third O site, O(3) is bonded to two equivalent Ti(2) and three equivalent Ti(1) atoms to form OTi5 square pyramids that share corners with two equivalent O(1)Ti6 octahedra, edges with three equivalent O(1)Ti6 octahedra, and edges with four equivalent O(3)Ti5 square pyramids. The corner-sharing octahedral tilt angles are 4°. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Ti(2) atoms.