MgV2CdO6 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. V(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), and three equivalent O(2) atoms. Cd(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form edge-sharing CdO6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one V(1), and one Cd(1) atom to form distorted OMg2VCd trigonal pyramids that share corners with three equivalent O(2)MgV3 tetrahedra, corners with five equivalent O(1)Mg2VCd trigonal pyramids, edges with two equivalent O(2)MgV3 tetrahedra, and  an edgeedge with one O(1)Mg2VCd trigonal pyramid. In the second O site, O(2) is bonded to one Mg(1) and three equivalent V(1) atoms to form OMgV3 tetrahedra that share corners with three equivalent O(2)MgV3 tetrahedra, corners with three equivalent O(1)Mg2VCd trigonal pyramids, edges with two equivalent O(2)MgV3 tetrahedra, and edges with two equivalent O(1)Mg2VCd trigonal pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to one V(1) and two equivalent Cd(1) atoms.
MgV2CdO6 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Both Mg(1)-O(2) bond lengths are 2.03 Å. All Mg(1)-O(1) bond lengths are 2.25 Å. V(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), and three equivalent O(2) atoms. The V(1)-O(1) bond length is 1.92 Å. The V(1)-O(3) bond length is 1.70 Å. There are two shorter (1.97 Å) and one longer (2.01 Å) V(1)-O(2) bond length. Cd(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form edge-sharing CdO6 octahedra. Both Cd(1)-O(1) bond lengths are 2.20 Å. All Cd(1)-O(3) bond lengths are 2.46 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one V(1), and one Cd(1) atom to form distorted OMg2VCd trigonal pyramids that share corners with three equivalent O(2)MgV3 tetrahedra, corners with five equivalent O(1)Mg2VCd trigonal pyramids, edges with two equivalent O(2)MgV3 tetrahedra, and  an edgeedge with one O(1)Mg2VCd trigonal pyramid. In the second O site, O(2) is bonded to one Mg(1) and three equivalent V(1) atoms to form OMgV3 tetrahedra that share corners with three equivalent O(2)MgV3 tetrahedra, corners with three equivalent O(1)Mg2VCd trigonal pyramids, edges with two equivalent O(2)MgV3 tetrahedra, and edges with two equivalent O(1)Mg2VCd trigonal pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to one V(1) and two equivalent Cd(1) atoms.