Mg(CoO2)4 is beta indium sulfide-derived structured and crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form MgO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra, corners with three equivalent Co(2)O6 octahedra, corners with three equivalent Co(3)O6 octahedra, and corners with three equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, 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. In the second Co site, Co(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. In the third Co site, Co(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. In the fourth Co site, Co(4) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Co(1), one Co(2), and one Co(3) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Co(2), one Co(3), and one Co(4) atom. In the third O site, O(3) is bonded to one Mg(1), one Co(1), one Co(2), and one Co(3) atom to form a mixture of distorted corner and edge-sharing OMgCo3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Co(1), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing OMgCo3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(2), one Co(3), and one Co(4) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Co(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Co(1), one Co(3), and one Co(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Co(1), one Co(2), and one Co(4) atom.
Mg(CoO2)4 is beta indium sulfide-derived structured and crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form MgO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra, corners with three equivalent Co(2)O6 octahedra, corners with three equivalent Co(3)O6 octahedra, and corners with three equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. The Mg(1)-O(3) bond length is 1.98 Å. The Mg(1)-O(4) bond length is 1.99 Å. The Mg(1)-O(5) bond length is 2.00 Å. The Mg(1)-O(6) bond length is 2.00 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, 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 Co(1)-O(1) bond length is 2.03 Å. The Co(1)-O(3) bond length is 2.02 Å. The Co(1)-O(4) bond length is 2.08 Å. The Co(1)-O(6) bond length is 1.91 Å. The Co(1)-O(7) bond length is 2.17 Å. The Co(1)-O(8) bond length is 1.82 Å. In the second Co site, Co(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The Co(2)-O(1) bond length is 1.80 Å. The Co(2)-O(2) bond length is 2.09 Å. The Co(2)-O(3) bond length is 1.93 Å. The Co(2)-O(5) bond length is 2.10 Å. The Co(2)-O(6) bond length is 2.03 Å. The Co(2)-O(8) bond length is 2.01 Å. In the third Co site, Co(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The Co(3)-O(1) bond length is 2.08 Å. The Co(3)-O(2) bond length is 1.88 Å. The Co(3)-O(3) bond length is 2.05 Å. The Co(3)-O(4) bond length is 2.03 Å. The Co(3)-O(5) bond length is 1.97 Å. The Co(3)-O(7) bond length is 2.11 Å. In the fourth Co site, Co(4) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The Co(4)-O(2) bond length is 1.91 Å. The Co(4)-O(4) bond length is 1.90 Å. The Co(4)-O(5) bond length is 1.97 Å. The Co(4)-O(6) bond length is 2.18 Å. The Co(4)-O(7) bond length is 1.74 Å. The Co(4)-O(8) bond length is 2.13 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Co(1), one Co(2), and one Co(3) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Co(2), one Co(3), and one Co(4) atom. In the third O site, O(3) is bonded to one Mg(1), one Co(1), one Co(2), and one Co(3) atom to form a mixture of distorted corner and edge-sharing OMgCo3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Co(1), one Co(3), and one Co(4) atom to form a mixture of distorted corner and edge-sharing OMgCo3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(2), one Co(3), and one Co(4) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Co(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Co(1), one Co(3), and one Co(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Co(1), one Co(2), and one Co(4) atom.