MgTi2(CoO2)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(1), and two equivalent O(6) atoms. In the second Ti site, Ti(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(6) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(6) atoms. In the second Co site, Co(2) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. In the third Co site, Co(3) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Co(2) atom to form OMgTi2Co tetrahedra that share  a cornercorner with one O(1)MgTi2Co tetrahedra, corners with two equivalent O(2)MgCo3 tetrahedra, corners with two equivalent O(3)MgCo3 tetrahedra, and  a faceface with one O(1)MgTi2Co tetrahedra. In the second O site, O(2) is bonded to one Mg(1), one Co(2), and two equivalent Co(3) atoms to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(3)MgCo3 tetrahedra, corners with four equivalent O(1)MgTi2Co tetrahedra, and  a faceface with one O(3)MgCo3 tetrahedra. In the third O site, O(3) is bonded to one Mg(1), one Co(2), and two equivalent Co(3) atoms to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(2)MgCo3 tetrahedra, corners with four equivalent O(1)MgTi2Co tetrahedra, and  a faceface with one O(2)MgCo3 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ti(2), one Co(1), and two equivalent Co(3) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ti(1), one Co(1), and two equivalent Co(3) atoms. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Co(1), and one Co(3) atom.
MgTi2(CoO2)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Mg(1)-O(2) bond length is 1.93 Å. The Mg(1)-O(3) bond length is 1.93 Å. Both Mg(1)-O(1) bond lengths are 2.04 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(1), and two equivalent O(6) atoms. The Ti(1)-O(5) bond length is 1.86 Å. Both Ti(1)-O(1) bond lengths are 2.02 Å. Both Ti(1)-O(6) bond lengths are 2.04 Å. In the second Ti site, Ti(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(6) atoms. The Ti(2)-O(4) bond length is 1.86 Å. Both Ti(2)-O(1) bond lengths are 2.03 Å. Both Ti(2)-O(6) bond lengths are 2.04 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(6) atoms. The Co(1)-O(4) bond length is 2.09 Å. The Co(1)-O(5) bond length is 2.09 Å. Both Co(1)-O(6) bond lengths are 2.15 Å. In the second Co site, Co(2) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Co(2)-O(2) bond length is 1.93 Å. The Co(2)-O(3) bond length is 1.94 Å. Both Co(2)-O(1) bond lengths are 2.14 Å. In the third Co site, Co(3) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Co(3)-O(2) bond length is 2.09 Å. The Co(3)-O(3) bond length is 2.08 Å. The Co(3)-O(4) bond length is 2.11 Å. The Co(3)-O(5) bond length is 2.11 Å. The Co(3)-O(6) bond length is 2.04 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Co(2) atom to form OMgTi2Co tetrahedra that share  a cornercorner with one O(1)MgTi2Co tetrahedra, corners with two equivalent O(2)MgCo3 tetrahedra, corners with two equivalent O(3)MgCo3 tetrahedra, and  a faceface with one O(1)MgTi2Co tetrahedra. In the second O site, O(2) is bonded to one Mg(1), one Co(2), and two equivalent Co(3) atoms to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(3)MgCo3 tetrahedra, corners with four equivalent O(1)MgTi2Co tetrahedra, and  a faceface with one O(3)MgCo3 tetrahedra. In the third O site, O(3) is bonded to one Mg(1), one Co(2), and two equivalent Co(3) atoms to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(2)MgCo3 tetrahedra, corners with four equivalent O(1)MgTi2Co tetrahedra, and  a faceface with one O(2)MgCo3 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ti(2), one Co(1), and two equivalent Co(3) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ti(1), one Co(1), and two equivalent Co(3) atoms. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Co(1), and one Co(3) atom.