Mg(CoO2)4 is beta indium sulfide-derived structured and crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form MgO4 tetrahedra that share corners with six equivalent Co(1)O6 octahedra and corners with six equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. In the second Co site, Co(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. There are four 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(2), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded to one Mg(1), one Co(1), and two equivalent Co(2) atoms to form a mixture of distorted edge and corner-sharing OMgCo3 tetrahedra. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Co(2) and two equivalent Co(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Co(1) and two equivalent Co(2) atoms.
Mg(CoO2)4 is beta indium sulfide-derived structured and crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form MgO4 tetrahedra that share corners with six equivalent Co(1)O6 octahedra and corners with six equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. Both Mg(1)-O(1) bond lengths are 2.01 Å. Both Mg(1)-O(2) bond lengths are 1.96 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The Co(1)-O(2) bond length is 1.93 Å. The Co(1)-O(4) bond length is 1.86 Å. There is one shorter (1.94 Å) and one longer (1.97 Å) Co(1)-O(1) bond length. There is one shorter (1.84 Å) and one longer (1.89 Å) Co(1)-O(3) bond length. In the second Co site, Co(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The Co(2)-O(1) bond length is 2.05 Å. The Co(2)-O(3) bond length is 2.08 Å. There is one shorter (1.98 Å) and one longer (2.04 Å) Co(2)-O(2) bond length. There is one shorter (1.89 Å) and one longer (2.07 Å) Co(2)-O(4) bond length. There are four 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(2), and two equivalent Co(1) atoms. In the second O site, O(2) is bonded to one Mg(1), one Co(1), and two equivalent Co(2) atoms to form a mixture of distorted edge and corner-sharing OMgCo3 tetrahedra. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Co(2) and two equivalent Co(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Co(1) and two equivalent Co(2) atoms.