MgTi4O8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form MgO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Ti(1)O4 tetrahedra, corners with two equivalent Ti(2)O5 trigonal bipyramids, and corners with two equivalent Ti(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-35°. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(4), and one O(8) atom to form TiO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Ti(3)O5 trigonal bipyramid, and corners with two equivalent Ti(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 45-56°. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted TiO5 trigonal bipyramids that share corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(1)O4 tetrahedra,  a cornercorner with one Ti(3)O5 trigonal bipyramid, edges with two equivalent Ti(4)O6 octahedra, and  an edgeedge with one Ti(3)O5 trigonal bipyramid. In the third Ti site, Ti(3) is bonded to one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted TiO5 trigonal bipyramids that share corners with three equivalent Ti(4)O6 octahedra,  a cornercorner with one Ti(1)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Ti(2)O5 trigonal bipyramid,  an edgeedge with one Ti(4)O6 octahedra, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 9-68°. In the fourth Ti site, Ti(4) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form TiO6 octahedra that share corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(1)O4 tetrahedra, corners with three equivalent Ti(3)O5 trigonal bipyramids,  an edgeedge with one Ti(3)O5 trigonal bipyramid, and edges with two equivalent Ti(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Mg(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ti(1), one Ti(2), and one Ti(4) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ti(2), one Ti(3), and one Ti(4) atom. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Ti(1), and one Ti(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Ti(3), and one Ti(4) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Ti(2), one Ti(3), and one Ti(4) atom. In the seventh O site, O(7) is bonded in a T-shaped geometry to one Ti(2), one Ti(3), and one Ti(4) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ti(1), one Ti(3), and one Ti(4) atom.
MgTi4O8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form MgO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Ti(1)O4 tetrahedra, corners with two equivalent Ti(2)O5 trigonal bipyramids, and corners with two equivalent Ti(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-35°. The Mg(1)-O(1) bond length is 1.99 Å. The Mg(1)-O(3) bond length is 1.98 Å. The Mg(1)-O(4) bond length is 2.02 Å. The Mg(1)-O(5) bond length is 1.96 Å. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(4), and one O(8) atom to form TiO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Ti(3)O5 trigonal bipyramid, and corners with two equivalent Ti(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 45-56°. The Ti(1)-O(1) bond length is 1.75 Å. The Ti(1)-O(2) bond length is 1.85 Å. The Ti(1)-O(4) bond length is 1.88 Å. The Ti(1)-O(8) bond length is 1.92 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted TiO5 trigonal bipyramids that share corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(1)O4 tetrahedra,  a cornercorner with one Ti(3)O5 trigonal bipyramid, edges with two equivalent Ti(4)O6 octahedra, and  an edgeedge with one Ti(3)O5 trigonal bipyramid. The Ti(2)-O(2) bond length is 1.94 Å. The Ti(2)-O(3) bond length is 2.03 Å. The Ti(2)-O(4) bond length is 2.03 Å. The Ti(2)-O(6) bond length is 1.95 Å. The Ti(2)-O(7) bond length is 1.93 Å. In the third Ti site, Ti(3) is bonded to one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted TiO5 trigonal bipyramids that share corners with three equivalent Ti(4)O6 octahedra,  a cornercorner with one Ti(1)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra,  a cornercorner with one Ti(2)O5 trigonal bipyramid,  an edgeedge with one Ti(4)O6 octahedra, and  an edgeedge with one Ti(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 9-68°. The Ti(3)-O(3) bond length is 2.09 Å. The Ti(3)-O(5) bond length is 1.96 Å. The Ti(3)-O(6) bond length is 2.00 Å. The Ti(3)-O(7) bond length is 1.99 Å. The Ti(3)-O(8) bond length is 1.94 Å. In the fourth Ti site, Ti(4) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form TiO6 octahedra that share corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(1)O4 tetrahedra, corners with three equivalent Ti(3)O5 trigonal bipyramids,  an edgeedge with one Ti(3)O5 trigonal bipyramid, and edges with two equivalent Ti(2)O5 trigonal bipyramids. The Ti(4)-O(2) bond length is 2.13 Å. The Ti(4)-O(3) bond length is 2.03 Å. The Ti(4)-O(5) bond length is 1.89 Å. The Ti(4)-O(6) bond length is 1.97 Å. The Ti(4)-O(7) bond length is 2.06 Å. The Ti(4)-O(8) bond length is 2.11 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Mg(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ti(1), one Ti(2), and one Ti(4) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ti(2), one Ti(3), and one Ti(4) atom. In the fourth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Ti(1), and one Ti(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Ti(3), and one Ti(4) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Ti(2), one Ti(3), and one Ti(4) atom. In the seventh O site, O(7) is bonded in a T-shaped geometry to one Ti(2), one Ti(3), and one Ti(4) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ti(1), one Ti(3), and one Ti(4) atom.