MgV4(CoO6)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form VO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and corners with two equivalent V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 29-61°. In the second V site, V(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and corners with two equivalent V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-69°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent V(2)O4 tetrahedra, corners with four equivalent V(1)O4 tetrahedra, and edges with two equivalent Co(2)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and edges with two equivalent Co(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one V(1), one Co(1), and one Co(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one V(1), and one Co(1) atom. In the third O site, O(3) is bonded to one Mg(1), one V(2), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing OMgVCo2 tetrahedra. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one V(1) and one V(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Mg(1), one V(1), and one V(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one V(2) and one Co(2) atom.
MgV4(CoO6)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Both Mg(1)-O(2) bond lengths are 2.61 Å. Both Mg(1)-O(3) bond lengths are 2.06 Å. Both Mg(1)-O(5) bond lengths are 2.11 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form VO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and corners with two equivalent V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 29-61°. The V(1)-O(1) bond length is 1.73 Å. The V(1)-O(2) bond length is 1.72 Å. The V(1)-O(4) bond length is 1.74 Å. The V(1)-O(5) bond length is 1.82 Å. In the second V site, V(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and corners with two equivalent V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 24-69°. The V(2)-O(3) bond length is 1.82 Å. The V(2)-O(4) bond length is 1.89 Å. The V(2)-O(5) bond length is 1.95 Å. The V(2)-O(6) bond length is 1.69 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent V(2)O4 tetrahedra, corners with four equivalent V(1)O4 tetrahedra, and edges with two equivalent Co(2)O6 octahedra. Both Co(1)-O(1) bond lengths are 2.09 Å. Both Co(1)-O(2) bond lengths are 2.07 Å. Both Co(1)-O(3) bond lengths are 2.18 Å. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and edges with two equivalent Co(1)O6 octahedra. Both Co(2)-O(1) bond lengths are 2.17 Å. Both Co(2)-O(3) bond lengths are 2.15 Å. Both Co(2)-O(6) bond lengths are 1.99 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one V(1), one Co(1), and one Co(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one V(1), and one Co(1) atom. In the third O site, O(3) is bonded to one Mg(1), one V(2), one Co(1), and one Co(2) atom to form a mixture of distorted corner and edge-sharing OMgVCo2 tetrahedra. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one V(1) and one V(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Mg(1), one V(1), and one V(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one V(2) and one Co(2) atom.