MgCo4NiO8 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-16°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with six equivalent Co(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. In the second Co site, Co(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with six equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. In the third Co site, Co(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) 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, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. In the fourth Co site, Co(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) 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, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-16°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Mg(1), one Co(3), one Co(4), and one Ni(1) atom. In the second O site, O(2) is bonded to one Mg(1), one Co(1), one Co(2), one Co(4), and one Ni(1) atom to form a mixture of edge and corner-sharing OMgCo3Ni square pyramids. In the third O site, O(3) is bonded to one Mg(1), one Co(1), one Co(2), one Co(3), and one Ni(1) atom to form a mixture of edge and corner-sharing OMgCo3Ni square pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Co(1), one Co(2), one Co(3), and one Co(4) atom.
MgCo4NiO8 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-16°. Both Mg(1)-O(1) bond lengths are 2.06 Å. Both Mg(1)-O(2) bond lengths are 2.09 Å. Both Mg(1)-O(3) bond lengths are 2.07 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with six equivalent Co(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. Both Co(1)-O(2) bond lengths are 2.01 Å. Both Co(1)-O(3) bond lengths are 2.07 Å. Both Co(1)-O(4) bond lengths are 2.02 Å. In the second Co site, Co(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with six equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. Both Co(2)-O(2) bond lengths are 2.17 Å. Both Co(2)-O(3) bond lengths are 2.12 Å. Both Co(2)-O(4) bond lengths are 2.07 Å. In the third Co site, Co(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) 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, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. Both Co(3)-O(1) bond lengths are 1.90 Å. Both Co(3)-O(3) bond lengths are 1.91 Å. Both Co(3)-O(4) bond lengths are 1.93 Å. In the fourth Co site, Co(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) 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, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. Both Co(4)-O(1) bond lengths are 1.89 Å. Both Co(4)-O(2) bond lengths are 1.92 Å. Both Co(4)-O(4) bond lengths are 1.94 Å. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-16°. Both Ni(1)-O(1) bond lengths are 2.05 Å. Both Ni(1)-O(2) bond lengths are 2.11 Å. Both Ni(1)-O(3) bond lengths are 2.10 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a see-saw-like geometry to one Mg(1), one Co(3), one Co(4), and one Ni(1) atom. In the second O site, O(2) is bonded to one Mg(1), one Co(1), one Co(2), one Co(4), and one Ni(1) atom to form a mixture of edge and corner-sharing OMgCo3Ni square pyramids. In the third O site, O(3) is bonded to one Mg(1), one Co(1), one Co(2), one Co(3), and one Ni(1) atom to form a mixture of edge and corner-sharing OMgCo3Ni square pyramids. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Co(1), one Co(2), one Co(3), and one Co(4) atom.