Li2MgCo3O8 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form LiO6 octahedra that share corners with six equivalent Co(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-11°. In the second Li site, Li(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form distorted LiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-16°. Mg(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-16°. There are two inequivalent Co sites. In the first Co site, Co(1) 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 Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(2)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-11°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Li(1), one Co(2), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a see-saw-like geometry to one Li(2), one Mg(1), and two equivalent Co(1) atoms. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Mg(1), one Co(1), and one Co(2) atom to form a mixture of corner and edge-sharing OLi2MgCo2 square pyramids.
Li2MgCo3O8 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form LiO6 octahedra that share corners with six equivalent Co(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-11°. Both Li(1)-O(1) bond lengths are 2.14 Å. All Li(1)-O(3) bond lengths are 2.24 Å. In the second Li site, Li(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form distorted LiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-16°. Both Li(2)-O(2) bond lengths are 2.08 Å. All Li(2)-O(3) bond lengths are 2.12 Å. Mg(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-16°. Both Mg(1)-O(2) bond lengths are 2.03 Å. All Mg(1)-O(3) bond lengths are 2.04 Å. There are two inequivalent Co sites. In the first Co site, Co(1) 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 Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(2)O6 octahedra. Both Co(1)-O(1) bond lengths are 1.93 Å. Both Co(1)-O(2) bond lengths are 1.87 Å. Both Co(1)-O(3) bond lengths are 1.87 Å. In the second Co site, Co(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-11°. Both Co(2)-O(1) bond lengths are 1.95 Å. All Co(2)-O(3) bond lengths are 1.90 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 Li(1), one Co(2), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a see-saw-like geometry to one Li(2), one Mg(1), and two equivalent Co(1) atoms. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Mg(1), one Co(1), and one Co(2) atom to form a mixture of corner and edge-sharing OLi2MgCo2 square pyramids.