MgCo3SbO8 crystallizes in the monoclinic C2/m 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 Sb(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-9°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Sb(1)O6 octahedra. Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-9°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Sb(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Co(2), and one Sb(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Co(1) and two equivalent Co(2) atoms.
MgCo3SbO8 crystallizes in the monoclinic C2/m 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 Sb(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-9°. Both Mg(1)-O(2) bond lengths are 2.24 Å. All Mg(1)-O(1) bond lengths are 2.16 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Sb(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. Both Co(1)-O(3) bond lengths are 1.94 Å. All Co(1)-O(1) bond lengths are 1.94 Å. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Sb(1)O6 octahedra. Both Co(2)-O(1) bond lengths are 2.06 Å. Both Co(2)-O(2) bond lengths are 2.04 Å. Both Co(2)-O(3) bond lengths are 1.94 Å. Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-9°. Both Sb(1)-O(2) bond lengths are 2.02 Å. All Sb(1)-O(1) bond lengths are 2.05 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Sb(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Co(2), and one Sb(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Co(1) and two equivalent Co(2) atoms.