Mo2O3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Mo sites. In the first Mo site, Mo(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 MoO6 octahedra. The corner-sharing octahedra are not tilted. In the second Mo site, Mo(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 Mo(2) and four equivalent Mo(1) atoms to form OMo6 octahedra that share corners with four equivalent O(3)Mo5 square pyramids, edges with two equivalent O(1)Mo6 octahedra, and edges with six equivalent O(3)Mo5 square pyramids. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mo(1) and two equivalent Mo(2) atoms. In the third O site, O(3) is bonded to two equivalent Mo(2) and three equivalent Mo(1) atoms to form OMo5 square pyramids that share corners with two equivalent O(1)Mo6 octahedra, edges with three equivalent O(1)Mo6 octahedra, and edges with four equivalent O(3)Mo5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent Mo(2) atoms.
Mo2O3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Mo sites. In the first Mo site, Mo(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 MoO6 octahedra. The corner-sharing octahedra are not tilted. The Mo(1)-O(2) bond length is 2.08 Å. Both Mo(1)-O(1) bond lengths are 2.31 Å. There are two shorter (2.19 Å) and one longer (2.25 Å) Mo(1)-O(3) bond length. In the second Mo site, Mo(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 Mo(2)-O(1) bond length is 2.57 Å. The Mo(2)-O(4) bond length is 1.96 Å. Both Mo(2)-O(2) bond lengths are 2.08 Å. Both Mo(2)-O(3) bond lengths are 2.52 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mo(2) and four equivalent Mo(1) atoms to form OMo6 octahedra that share corners with four equivalent O(3)Mo5 square pyramids, edges with two equivalent O(1)Mo6 octahedra, and edges with six equivalent O(3)Mo5 square pyramids. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mo(1) and two equivalent Mo(2) atoms. In the third O site, O(3) is bonded to two equivalent Mo(2) and three equivalent Mo(1) atoms to form OMo5 square pyramids that share corners with two equivalent O(1)Mo6 octahedra, edges with three equivalent O(1)Mo6 octahedra, and edges with four equivalent O(3)Mo5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent Mo(2) atoms.