MgTi4O8 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(4), one O(6), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with eight equivalent Ti(2)O6 octahedra, and  a faceface with one Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-58°. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(6), and two equivalent O(2) atoms. In the second Ti site, Ti(2) 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 TiO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, edges with two equivalent Ti(2)O6 octahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-58°. In the third Ti site, Ti(3) is bonded to one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form TiO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, edges with four equivalent Ti(2)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ti(1) and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ti(1), one Ti(2), and one Ti(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Ti(1), one Ti(3), and two equivalent Ti(2) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Ti(3), and two equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OMgTi3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ti(2), and one Ti(3) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Ti(1), and two equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OMgTi3 trigonal pyramids.
MgTi4O8 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(4), one O(6), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with eight equivalent Ti(2)O6 octahedra, and  a faceface with one Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-58°. The Mg(1)-O(4) bond length is 2.05 Å. The Mg(1)-O(6) bond length is 2.00 Å. Both Mg(1)-O(2) bond lengths are 2.28 Å. Both Mg(1)-O(5) bond lengths are 2.09 Å. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(6), and two equivalent O(2) atoms. The Ti(1)-O(1) bond length is 1.87 Å. The Ti(1)-O(3) bond length is 2.12 Å. The Ti(1)-O(6) bond length is 2.08 Å. Both Ti(1)-O(2) bond lengths are 1.91 Å. In the second Ti site, Ti(2) 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 TiO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, edges with two equivalent Ti(2)O6 octahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-58°. The Ti(2)-O(1) bond length is 2.04 Å. The Ti(2)-O(2) bond length is 2.08 Å. The Ti(2)-O(3) bond length is 2.15 Å. The Ti(2)-O(4) bond length is 2.09 Å. The Ti(2)-O(5) bond length is 1.93 Å. The Ti(2)-O(6) bond length is 2.06 Å. In the third Ti site, Ti(3) is bonded to one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form TiO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, edges with four equivalent Ti(2)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. The Ti(3)-O(3) bond length is 1.99 Å. The Ti(3)-O(4) bond length is 1.98 Å. Both Ti(3)-O(2) bond lengths are 2.13 Å. Both Ti(3)-O(5) bond lengths are 1.91 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ti(1) and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ti(1), one Ti(2), and one Ti(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Ti(1), one Ti(3), and two equivalent Ti(2) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Ti(3), and two equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OMgTi3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ti(2), and one Ti(3) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Ti(1), and two equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OMgTi3 trigonal pyramids.