MgMo3O8 crystallizes in the orthorhombic Cmc2_1 space group. Mg(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form MgO4 tetrahedra that share corners with three equivalent Mo(1)O6 octahedra and corners with six equivalent Mo(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-60°. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(6) atoms to form MoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra and edges with four equivalent Mo(2)O6 octahedra. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mo(1)O6 octahedra, and edges with two equivalent Mo(2)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mo(1) and two equivalent Mo(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Mg(1), one Mo(1), and two equivalent Mo(2) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Mo(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1), one Mo(1), and one Mo(2) atom. In the fifth O site, O(5) is bonded in an L-shaped geometry to two equivalent Mo(2) atoms. In the sixth O site, O(6) is bonded in a water-like geometry to one Mo(1) and one Mo(2) atom.
MgMo3O8 crystallizes in the orthorhombic Cmc2_1 space group. Mg(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form MgO4 tetrahedra that share corners with three equivalent Mo(1)O6 octahedra and corners with six equivalent Mo(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-60°. The Mg(1)-O(2) bond length is 2.04 Å. The Mg(1)-O(3) bond length is 2.05 Å. Both Mg(1)-O(4) bond lengths are 2.01 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(6) atoms to form MoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra and edges with four equivalent Mo(2)O6 octahedra. The Mo(1)-O(1) bond length is 2.11 Å. The Mo(1)-O(2) bond length is 2.11 Å. Both Mo(1)-O(4) bond lengths are 2.11 Å. Both Mo(1)-O(6) bond lengths are 1.87 Å. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mo(1)O6 octahedra, and edges with two equivalent Mo(2)O6 octahedra. The Mo(2)-O(1) bond length is 2.08 Å. The Mo(2)-O(2) bond length is 2.20 Å. The Mo(2)-O(3) bond length is 2.03 Å. The Mo(2)-O(4) bond length is 1.99 Å. The Mo(2)-O(5) bond length is 1.96 Å. The Mo(2)-O(6) bond length is 2.07 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mo(1) and two equivalent Mo(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Mg(1), one Mo(1), and two equivalent Mo(2) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Mo(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1), one Mo(1), and one Mo(2) atom. In the fifth O site, O(5) is bonded in an L-shaped geometry to two equivalent Mo(2) atoms. In the sixth O site, O(6) is bonded in a water-like geometry to one Mo(1) and one Mo(2) atom.