CuMgVO4 crystallizes in the orthorhombic Cmcm space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent V(1)O4 tetrahedra, corners with six equivalent Cu(1)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. V(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with six equivalent Mg(1)O6 octahedra, corners with two equivalent Cu(1)O4 tetrahedra, and  an edgeedge with one Cu(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-53°. Cu(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted CuO4 tetrahedra that share corners with six equivalent Mg(1)O6 octahedra, corners with two equivalent V(1)O4 tetrahedra, and  an edgeedge with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 68-70°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one V(1), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMg2VCu tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one V(1), and one Cu(1) atom.
CuMgVO4 crystallizes in the orthorhombic Cmcm space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent V(1)O4 tetrahedra, corners with six equivalent Cu(1)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. Both Mg(1)-O(2) bond lengths are 2.12 Å. All Mg(1)-O(1) bond lengths are 2.15 Å. V(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with six equivalent Mg(1)O6 octahedra, corners with two equivalent Cu(1)O4 tetrahedra, and  an edgeedge with one Cu(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-53°. Both V(1)-O(1) bond lengths are 1.81 Å. Both V(1)-O(2) bond lengths are 1.74 Å. Cu(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted CuO4 tetrahedra that share corners with six equivalent Mg(1)O6 octahedra, corners with two equivalent V(1)O4 tetrahedra, and  an edgeedge with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 68-70°. Both Cu(1)-O(1) bond lengths are 2.22 Å. Both Cu(1)-O(2) bond lengths are 1.95 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one V(1), and one Cu(1) atom to form a mixture of distorted corner and edge-sharing OMg2VCu tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one V(1), and one Cu(1) atom.