Co4SbO8 crystallizes in the monoclinic C2/m space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with three equivalent Sb(1)O6 octahedra and corners with six equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-61°. 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 corners with six equivalent Co(1)O4 tetrahedra, 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(3) atoms to form SbO6 octahedra that share corners with six equivalent Co(1)O4 tetrahedra and edges with four equivalent Co(2)O6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(1) and two equivalent Co(2) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Co(1), two equivalent Co(2), and one Sb(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Co(1), one Co(2), and one Sb(1) atom.
Co4SbO8 crystallizes in the monoclinic C2/m space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form CoO4 tetrahedra that share corners with three equivalent Sb(1)O6 octahedra and corners with six equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-61°. The Co(1)-O(1) bond length is 1.96 Å. The Co(1)-O(2) bond length is 1.98 Å. Both Co(1)-O(3) bond lengths are 1.96 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 corners with six equivalent Co(1)O4 tetrahedra, 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 1.90 Å. Both Co(2)-O(2) bond lengths are 2.07 Å. Both Co(2)-O(3) bond lengths are 1.93 Å. Sb(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form SbO6 octahedra that share corners with six equivalent Co(1)O4 tetrahedra and edges with four equivalent Co(2)O6 octahedra. Both Sb(1)-O(2) bond lengths are 2.05 Å. All Sb(1)-O(3) bond lengths are 2.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(1) and two equivalent Co(2) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Co(1), two equivalent Co(2), and one Sb(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Co(1), one Co(2), and one Sb(1) atom.