V3Cd5O12 crystallizes in the monoclinic C2/c space group. There are two inequivalent V sites. In the first V site, V(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with two equivalent Cd(3)O6 octahedra and corners with four equivalent Cd(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. 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 corners with two equivalent Cd(3)O6 octahedra and corners with four equivalent Cd(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-64°. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(5) atoms. In the second Cd site, Cd(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. In the third Cd site, Cd(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form distorted CdO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and edges with two equivalent Cd(4)O6 octahedra. In the fourth Cd site, Cd(4) is bonded to one O(1), one O(2), one O(5), one O(6), and two equivalent O(4) atoms to form CdO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra,  an edgeedge with one Cd(3)O6 octahedra, and  an edgeedge with one Cd(4)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 Cd(3), and one Cd(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one V(1), one Cd(2), and one Cd(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one V(2), one Cd(3), and two equivalent Cd(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one V(2) and two equivalent Cd(4) atoms. In the fifth O site, O(5) is bonded to one V(2), one Cd(4), and two equivalent Cd(1) atoms to form a mixture of distorted corner and edge-sharing OVCd3 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one V(2), one Cd(3), and one Cd(4) atom.
V3Cd5O12 crystallizes in the monoclinic C2/c space group. There are two inequivalent V sites. In the first V site, V(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with two equivalent Cd(3)O6 octahedra and corners with four equivalent Cd(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. Both V(1)-O(1) bond lengths are 1.75 Å. Both V(1)-O(2) bond lengths are 1.76 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 corners with two equivalent Cd(3)O6 octahedra and corners with four equivalent Cd(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-64°. The V(2)-O(3) bond length is 1.80 Å. The V(2)-O(4) bond length is 1.71 Å. The V(2)-O(5) bond length is 1.79 Å. The V(2)-O(6) bond length is 1.74 Å. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(5) atoms. There are two shorter (2.49 Å) and two longer (2.55 Å) Cd(1)-O(5) bond lengths. In the second Cd site, Cd(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. Both Cd(2)-O(2) bond lengths are 2.31 Å. There are two shorter (2.41 Å) and two longer (2.77 Å) Cd(2)-O(3) bond lengths. In the third Cd site, Cd(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form distorted CdO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and edges with two equivalent Cd(4)O6 octahedra. Both Cd(3)-O(1) bond lengths are 2.35 Å. Both Cd(3)-O(3) bond lengths are 2.42 Å. Both Cd(3)-O(6) bond lengths are 2.35 Å. In the fourth Cd site, Cd(4) is bonded to one O(1), one O(2), one O(5), one O(6), and two equivalent O(4) atoms to form CdO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra,  an edgeedge with one Cd(3)O6 octahedra, and  an edgeedge with one Cd(4)O6 octahedra. The Cd(4)-O(1) bond length is 2.28 Å. The Cd(4)-O(2) bond length is 2.24 Å. The Cd(4)-O(5) bond length is 2.31 Å. The Cd(4)-O(6) bond length is 2.27 Å. There is one shorter (2.30 Å) and one longer (2.43 Å) Cd(4)-O(4) bond length. 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 Cd(3), and one Cd(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one V(1), one Cd(2), and one Cd(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one V(2), one Cd(3), and two equivalent Cd(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one V(2) and two equivalent Cd(4) atoms. In the fifth O site, O(5) is bonded to one V(2), one Cd(4), and two equivalent Cd(1) atoms to form a mixture of distorted corner and edge-sharing OVCd3 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one V(2), one Cd(3), and one Cd(4) atom.