MgCoO2 is Caswellsilverite-like structured and crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), two equivalent O(3), and three equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Co(1)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second Mg site, Mg(2) is bonded to one O(3), two equivalent O(4), and three equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Co(2)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second Co site, Co(2) is bonded to one O(4), two equivalent O(2), and three equivalent O(1) atoms to form CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Co(1), and three equivalent Co(2) atoms to form OMgCo5 octahedra that share corners with two equivalent O(2)Mg3Co3 octahedra, corners with two equivalent O(3)Mg3Co3 octahedra, corners with two equivalent O(4)Mg5Co octahedra, edges with two equivalent O(4)Mg5Co octahedra, edges with three equivalent O(2)Mg3Co3 octahedra, edges with three equivalent O(3)Mg3Co3 octahedra, and edges with four equivalent O(1)MgCo5 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second O site, O(2) is bonded to three equivalent Mg(2), one Co(1), and two equivalent Co(2) atoms to form OMg3Co3 octahedra that share corners with two equivalent O(3)Mg3Co3 octahedra, corners with two equivalent O(4)Mg5Co octahedra, corners with two equivalent O(1)MgCo5 octahedra, edges with two equivalent O(3)Mg3Co3 octahedra, edges with three equivalent O(4)Mg5Co octahedra, edges with three equivalent O(1)MgCo5 octahedra, and edges with four equivalent O(2)Mg3Co3 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and three equivalent Co(1) atoms to form OMg3Co3 octahedra that share corners with two equivalent O(2)Mg3Co3 octahedra, corners with two equivalent O(4)Mg5Co octahedra, corners with two equivalent O(1)MgCo5 octahedra, edges with two equivalent O(2)Mg3Co3 octahedra, edges with three equivalent O(4)Mg5Co octahedra, edges with three equivalent O(1)MgCo5 octahedra, and edges with four equivalent O(3)Mg3Co3 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the fourth O site, O(4) is bonded to two equivalent Mg(2), three equivalent Mg(1), and one Co(2) atom to form OMg5Co octahedra that share corners with two equivalent O(2)Mg3Co3 octahedra, corners with two equivalent O(3)Mg3Co3 octahedra, corners with two equivalent O(1)MgCo5 octahedra, edges with two equivalent O(1)MgCo5 octahedra, edges with three equivalent O(2)Mg3Co3 octahedra, edges with three equivalent O(3)Mg3Co3 octahedra, and edges with four equivalent O(4)Mg5Co octahedra. The corner-sharing octahedral tilt angles range from 0-2°.
MgCoO2 is Caswellsilverite-like structured and crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), two equivalent O(3), and three equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(2)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Co(1)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. The Mg(1)-O(1) bond length is 2.12 Å. Both Mg(1)-O(3) bond lengths are 2.12 Å. There are two shorter (2.12 Å) and one longer (2.14 Å) Mg(1)-O(4) bond length. In the second Mg site, Mg(2) is bonded to one O(3), two equivalent O(4), and three equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Co(2)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. The Mg(2)-O(3) bond length is 2.12 Å. Both Mg(2)-O(4) bond lengths are 2.13 Å. There is one shorter (2.11 Å) and two longer (2.12 Å) Mg(2)-O(2) bond lengths. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Co(2)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. The Co(1)-O(2) bond length is 2.17 Å. Both Co(1)-O(1) bond lengths are 2.13 Å. There are two shorter (2.13 Å) and one longer (2.20 Å) Co(1)-O(3) bond length. In the second Co site, Co(2) is bonded to one O(4), two equivalent O(2), and three equivalent O(1) atoms to form CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Co(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. The Co(2)-O(4) bond length is 2.17 Å. Both Co(2)-O(2) bond lengths are 2.14 Å. There are two shorter (2.15 Å) and one longer (2.18 Å) Co(2)-O(1) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Co(1), and three equivalent Co(2) atoms to form OMgCo5 octahedra that share corners with two equivalent O(2)Mg3Co3 octahedra, corners with two equivalent O(3)Mg3Co3 octahedra, corners with two equivalent O(4)Mg5Co octahedra, edges with two equivalent O(4)Mg5Co octahedra, edges with three equivalent O(2)Mg3Co3 octahedra, edges with three equivalent O(3)Mg3Co3 octahedra, and edges with four equivalent O(1)MgCo5 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second O site, O(2) is bonded to three equivalent Mg(2), one Co(1), and two equivalent Co(2) atoms to form OMg3Co3 octahedra that share corners with two equivalent O(3)Mg3Co3 octahedra, corners with two equivalent O(4)Mg5Co octahedra, corners with two equivalent O(1)MgCo5 octahedra, edges with two equivalent O(3)Mg3Co3 octahedra, edges with three equivalent O(4)Mg5Co octahedra, edges with three equivalent O(1)MgCo5 octahedra, and edges with four equivalent O(2)Mg3Co3 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and three equivalent Co(1) atoms to form OMg3Co3 octahedra that share corners with two equivalent O(2)Mg3Co3 octahedra, corners with two equivalent O(4)Mg5Co octahedra, corners with two equivalent O(1)MgCo5 octahedra, edges with two equivalent O(2)Mg3Co3 octahedra, edges with three equivalent O(4)Mg5Co octahedra, edges with three equivalent O(1)MgCo5 octahedra, and edges with four equivalent O(3)Mg3Co3 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the fourth O site, O(4) is bonded to two equivalent Mg(2), three equivalent Mg(1), and one Co(2) atom to form OMg5Co octahedra that share corners with two equivalent O(2)Mg3Co3 octahedra, corners with two equivalent O(3)Mg3Co3 octahedra, corners with two equivalent O(1)MgCo5 octahedra, edges with two equivalent O(1)MgCo5 octahedra, edges with three equivalent O(2)Mg3Co3 octahedra, edges with three equivalent O(3)Mg3Co3 octahedra, and edges with four equivalent O(4)Mg5Co octahedra. The corner-sharing octahedral tilt angles range from 0-2°.