MgTi2(CoO2)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(4), one O(5), and two equivalent O(1) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(6) atoms to form distorted TiO5 trigonal bipyramids that share corners with two equivalent Co(3)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, edges with two equivalent Ti(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles are 74°. In the second Ti site, Ti(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(6) atoms to form distorted TiO6 octahedra that share corners with three equivalent Co(2)O4 tetrahedra, edges with four equivalent Co(3)O6 octahedra, and edges with two equivalent Ti(1)O5 trigonal bipyramids. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), and two equivalent O(6) atoms. In the second Co site, Co(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form CoO4 tetrahedra that share corners with three equivalent Ti(2)O6 octahedra, corners with six equivalent Co(3)O6 octahedra, and corners with three equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 50-84°. 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(6) atom to form distorted CoO6 octahedra that share corners with three equivalent Co(2)O4 tetrahedra,  a cornercorner with one Ti(1)O5 trigonal bipyramid, edges with two equivalent Ti(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and  an edgeedge with one Ti(1)O5 trigonal bipyramid. 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), one Co(2), and one Co(3) atom to form distorted OMgTi2Co2 trigonal bipyramids that share  a cornercorner with one O(1)MgTi2Co2 trigonal bipyramid,  a cornercorner with one O(4)MgTiCo2 trigonal pyramid,  an edgeedge with one O(4)MgTiCo2 trigonal pyramid, and  a faceface with one O(1)MgTi2Co2 trigonal bipyramid. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Ti(1), one Co(1), one Co(2), and two equivalent Co(3) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ti(2), one Co(1), one Co(2), and two equivalent Co(3) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Ti(2), and two equivalent Co(3) atoms to form a mixture of edge and corner-sharing OMgTiCo2 trigonal pyramids. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Mg(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 distorted rectangular see-saw-like geometry to one O(4), one O(5), and two equivalent O(1) atoms. The Mg(1)-O(4) bond length is 1.90 Å. The Mg(1)-O(5) bond length is 1.90 Å. Both Mg(1)-O(1) bond lengths are 2.13 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(6) atoms to form distorted TiO5 trigonal bipyramids that share corners with two equivalent Co(3)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, edges with two equivalent Ti(2)O6 octahedra, and edges with two equivalent Co(3)O6 octahedra. The corner-sharing octahedral tilt angles are 74°. The Ti(1)-O(2) bond length is 1.83 Å. Both Ti(1)-O(1) bond lengths are 2.07 Å. Both Ti(1)-O(6) bond lengths are 1.94 Å. In the second Ti site, Ti(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(6) atoms to form distorted TiO6 octahedra that share corners with three equivalent Co(2)O4 tetrahedra, edges with four equivalent Co(3)O6 octahedra, and edges with two equivalent Ti(1)O5 trigonal bipyramids. The Ti(2)-O(3) bond length is 1.97 Å. The Ti(2)-O(4) bond length is 2.01 Å. Both Ti(2)-O(1) bond lengths are 2.36 Å. Both Ti(2)-O(6) bond lengths are 1.96 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), and two equivalent O(6) atoms. The Co(1)-O(2) bond length is 2.12 Å. The Co(1)-O(3) bond length is 2.24 Å. The Co(1)-O(5) bond length is 2.39 Å. Both Co(1)-O(6) bond lengths are 1.95 Å. In the second Co site, Co(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form CoO4 tetrahedra that share corners with three equivalent Ti(2)O6 octahedra, corners with six equivalent Co(3)O6 octahedra, and corners with three equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 50-84°. The Co(2)-O(2) bond length is 2.06 Å. The Co(2)-O(3) bond length is 2.10 Å. Both Co(2)-O(1) bond lengths are 2.04 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(6) atom to form distorted CoO6 octahedra that share corners with three equivalent Co(2)O4 tetrahedra,  a cornercorner with one Ti(1)O5 trigonal bipyramid, edges with two equivalent Ti(2)O6 octahedra, edges with two equivalent Co(3)O6 octahedra, and  an edgeedge with one Ti(1)O5 trigonal bipyramid. The Co(3)-O(1) bond length is 2.17 Å. The Co(3)-O(2) bond length is 2.41 Å. The Co(3)-O(3) bond length is 2.15 Å. The Co(3)-O(4) bond length is 2.04 Å. The Co(3)-O(5) bond length is 1.99 Å. The Co(3)-O(6) bond length is 2.32 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), one Co(2), and one Co(3) atom to form distorted OMgTi2Co2 trigonal bipyramids that share  a cornercorner with one O(1)MgTi2Co2 trigonal bipyramid,  a cornercorner with one O(4)MgTiCo2 trigonal pyramid,  an edgeedge with one O(4)MgTiCo2 trigonal pyramid, and  a faceface with one O(1)MgTi2Co2 trigonal bipyramid. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Ti(1), one Co(1), one Co(2), and two equivalent Co(3) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ti(2), one Co(1), one Co(2), and two equivalent Co(3) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Ti(2), and two equivalent Co(3) atoms to form a mixture of edge and corner-sharing OMgTiCo2 trigonal pyramids. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Mg(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.