MgV2CdO6 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) 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(3), one O(5), and two equivalent O(6) atoms to form a mixture of edge and corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 16°. In the second V site, V(2) is bonded to one O(1), one O(2), one O(4), one O(6), and two equivalent O(5) atoms to form a mixture of distorted edge and corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 25°. Cd(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one V(1), one V(2), and one Cd(1) atom to form distorted OMg2V2Cd trigonal bipyramids that share  a cornercorner with one O(4)MgVCd2 tetrahedra, corners with two equivalent O(1)Mg2V2Cd trigonal bipyramids,  a cornercorner with one O(5)MgV3 trigonal pyramid, edges with two equivalent O(4)MgVCd2 tetrahedra, and edges with two equivalent O(5)MgV3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one V(1), one V(2), and one Cd(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one V(1), and two equivalent Cd(1) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one V(2), and two equivalent Cd(1) atoms to form distorted OMgVCd2 tetrahedra that share corners with two equivalent O(4)MgVCd2 tetrahedra,  a cornercorner with one O(1)Mg2V2Cd trigonal bipyramid, corners with three equivalent O(5)MgV3 trigonal pyramids, and edges with two equivalent O(1)Mg2V2Cd trigonal bipyramids. In the fifth O site, O(5) is bonded to one Mg(1), one V(1), and two equivalent V(2) atoms to form distorted OMgV3 trigonal pyramids that share corners with three equivalent O(4)MgVCd2 tetrahedra,  a cornercorner with one O(1)Mg2V2Cd trigonal bipyramid, corners with two equivalent O(5)MgV3 trigonal pyramids, and edges with two equivalent O(1)Mg2V2Cd trigonal bipyramids. In the sixth O site, O(6) is bonded in a square co-planar geometry to one Mg(1), one V(2), and two equivalent V(1) atoms.
MgV2CdO6 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. The Mg(1)-O(3) bond length is 2.15 Å. The Mg(1)-O(4) bond length is 2.13 Å. The Mg(1)-O(5) bond length is 2.37 Å. The Mg(1)-O(6) bond length is 2.45 Å. Both Mg(1)-O(1) bond lengths are 1.99 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(3), one O(5), and two equivalent O(6) atoms to form a mixture of edge and corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 16°. The V(1)-O(1) bond length is 2.03 Å. The V(1)-O(2) bond length is 2.09 Å. The V(1)-O(3) bond length is 1.76 Å. The V(1)-O(5) bond length is 1.97 Å. Both V(1)-O(6) bond lengths are 1.98 Å. In the second V site, V(2) is bonded to one O(1), one O(2), one O(4), one O(6), and two equivalent O(5) atoms to form a mixture of distorted edge and corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 25°. The V(2)-O(1) bond length is 2.28 Å. The V(2)-O(2) bond length is 1.77 Å. The V(2)-O(4) bond length is 1.87 Å. The V(2)-O(6) bond length is 2.15 Å. Both V(2)-O(5) bond lengths are 2.01 Å. Cd(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. The Cd(1)-O(1) bond length is 2.45 Å. The Cd(1)-O(2) bond length is 2.16 Å. Both Cd(1)-O(3) bond lengths are 2.46 Å. Both Cd(1)-O(4) bond lengths are 2.36 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one V(1), one V(2), and one Cd(1) atom to form distorted OMg2V2Cd trigonal bipyramids that share  a cornercorner with one O(4)MgVCd2 tetrahedra, corners with two equivalent O(1)Mg2V2Cd trigonal bipyramids,  a cornercorner with one O(5)MgV3 trigonal pyramid, edges with two equivalent O(4)MgVCd2 tetrahedra, and edges with two equivalent O(5)MgV3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one V(1), one V(2), and one Cd(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one V(1), and two equivalent Cd(1) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one V(2), and two equivalent Cd(1) atoms to form distorted OMgVCd2 tetrahedra that share corners with two equivalent O(4)MgVCd2 tetrahedra,  a cornercorner with one O(1)Mg2V2Cd trigonal bipyramid, corners with three equivalent O(5)MgV3 trigonal pyramids, and edges with two equivalent O(1)Mg2V2Cd trigonal bipyramids. In the fifth O site, O(5) is bonded to one Mg(1), one V(1), and two equivalent V(2) atoms to form distorted OMgV3 trigonal pyramids that share corners with three equivalent O(4)MgVCd2 tetrahedra,  a cornercorner with one O(1)Mg2V2Cd trigonal bipyramid, corners with two equivalent O(5)MgV3 trigonal pyramids, and edges with two equivalent O(1)Mg2V2Cd trigonal bipyramids. In the sixth O site, O(6) is bonded in a square co-planar geometry to one Mg(1), one V(2), and two equivalent V(1) atoms.