MgTi2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(13), one O(3), and two equivalent O(1) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Ti(6)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra, and corners with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-62°. In the second Mg site, Mg(2) is bonded to one O(5), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Ti(2)O4 tetrahedra, corners with three equivalent Ti(7)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Ti(4)O6 octahedra. In the third Mg site, Mg(3) is bonded to one O(2), one O(8), two equivalent O(1), and two equivalent O(7) atoms to form MgO6 octahedra that share  a cornercorner with one Ti(2)O4 tetrahedra,  a cornercorner with one Ti(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. In the fourth Mg site, Mg(4) is bonded to one O(11), one O(15), two equivalent O(10), and two equivalent O(12) atoms to form MgO6 octahedra that share corners with three equivalent Ti(5)O4 tetrahedra, corners with three equivalent Ti(8)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, and edges with two equivalent Ti(6)O6 octahedra. In the fifth Mg site, Mg(5) is bonded to one O(14), one O(6), two equivalent O(12), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Ti(5)O4 tetrahedra,  a cornercorner with one Ti(7)O4 tetrahedra, corners with two equivalent Ti(2)O4 tetrahedra, corners with two equivalent Ti(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, and edges with four equivalent Ti(4)O6 octahedra. In the sixth Mg site, Mg(6) is bonded to one O(13), one O(18), two equivalent O(10), and two equivalent O(17) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Ti(8)O4 tetrahedra, corners with two equivalent Ti(5)O4 tetrahedra, corners with two equivalent Ti(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, and edges with four equivalent Ti(6)O6 octahedra. There are nine inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form TiO6 octahedra that share  a cornercorner with one Ti(2)O4 tetrahedra,  a cornercorner with one Ti(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. In the second Ti site, Ti(2) is bonded to one O(2), one O(9), and two equivalent O(4) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-59°. In the third Ti site, Ti(3) is bonded to one O(16), one O(3), two equivalent O(1), and two equivalent O(17) atoms to form TiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Ti(9)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Ti(6)O6 octahedra. In the fourth Ti site, Ti(4) is bonded to one O(11), one O(12), one O(14), one O(4), one O(6), and one O(9) atom to form TiO6 octahedra that share  a cornercorner with one Ti(5)O4 tetrahedra,  a cornercorner with one Ti(7)O4 tetrahedra, corners with two equivalent Ti(2)O4 tetrahedra, corners with two equivalent Ti(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Ti(4)O6 octahedra. In the fifth Ti site, Ti(5) is bonded to one O(15), one O(6), and two equivalent O(10) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Ti(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-58°. In the sixth Ti site, Ti(6) is bonded to one O(10), one O(13), one O(15), one O(16), one O(17), and one O(18) atom to form TiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Ti(8)O4 tetrahedra, corners with two equivalent Ti(5)O4 tetrahedra, corners with two equivalent Ti(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, and edges with two equivalent Ti(6)O6 octahedra. In the seventh Ti site, Ti(7) is bonded to one O(14), one O(5), and two equivalent O(7) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-60°. In the eighth Ti site, Ti(8) is bonded to one O(11), one O(18), and two equivalent O(12) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Ti(6)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-59°. In the ninth Ti site, Ti(9) is bonded to one O(16), one O(8), and two equivalent O(17) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra, and corners with four equivalent Ti(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-61°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(3), one Ti(1), and one Ti(3) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Ti(2), and two equivalent Ti(1) atoms. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ti(3), and two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded to one Mg(2), one Mg(5), one Ti(2), and one Ti(4) atom to form a mixture of distorted corner and edge-sharing OMg2Ti2 trigonal pyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Ti(7), and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mg(5), one Ti(5), and two equivalent Ti(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Ti(1), and one Ti(7) atom. In the eighth O site, O(8) is bonded in a distorted tetrahedral geometry to one Mg(3), one Ti(9), and two equivalent Ti(1) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Mg(2), one Ti(2), and two equivalent Ti(4) atoms. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(6), one Ti(5), and one Ti(6) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Ti(8), and two equivalent Ti(4) atoms. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(5), one Ti(4), and one Ti(8) atom. In the thirteenth O site, O(13) is bonded in a tetrahedral geometry to one Mg(1), one Mg(6), and two equivalent Ti(6) atoms. In the fourteenth O site, O(14) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Ti(7), and two equivalent Ti(4) atoms. In the fifteenth O site, O(15) is bonded in a distorted rectangular see-saw-like geometry to one Mg(4), one Ti(5), and two equivalent Ti(6) atoms. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Ti(3), one Ti(9), and two equivalent Ti(6) atoms. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Ti(3), one Ti(6), and one Ti(9) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Ti(8), and two equivalent Ti(6) atoms.
MgTi2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(13), one O(3), and two equivalent O(1) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Ti(6)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra, and corners with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-62°. The Mg(1)-O(13) bond length is 1.97 Å. The Mg(1)-O(3) bond length is 1.97 Å. Both Mg(1)-O(1) bond lengths are 1.97 Å. In the second Mg site, Mg(2) is bonded to one O(5), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Ti(2)O4 tetrahedra, corners with three equivalent Ti(7)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Ti(4)O6 octahedra. The Mg(2)-O(5) bond length is 2.12 Å. The Mg(2)-O(9) bond length is 2.15 Å. Both Mg(2)-O(4) bond lengths are 2.10 Å. Both Mg(2)-O(7) bond lengths are 2.10 Å. In the third Mg site, Mg(3) is bonded to one O(2), one O(8), two equivalent O(1), and two equivalent O(7) atoms to form MgO6 octahedra that share  a cornercorner with one Ti(2)O4 tetrahedra,  a cornercorner with one Ti(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. The Mg(3)-O(2) bond length is 2.18 Å. The Mg(3)-O(8) bond length is 2.06 Å. Both Mg(3)-O(1) bond lengths are 2.08 Å. Both Mg(3)-O(7) bond lengths are 2.10 Å. In the fourth Mg site, Mg(4) is bonded to one O(11), one O(15), two equivalent O(10), and two equivalent O(12) atoms to form MgO6 octahedra that share corners with three equivalent Ti(5)O4 tetrahedra, corners with three equivalent Ti(8)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, and edges with two equivalent Ti(6)O6 octahedra. The Mg(4)-O(11) bond length is 2.20 Å. The Mg(4)-O(15) bond length is 2.10 Å. Both Mg(4)-O(10) bond lengths are 2.09 Å. Both Mg(4)-O(12) bond lengths are 2.11 Å. In the fifth Mg site, Mg(5) is bonded to one O(14), one O(6), two equivalent O(12), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Ti(5)O4 tetrahedra,  a cornercorner with one Ti(7)O4 tetrahedra, corners with two equivalent Ti(2)O4 tetrahedra, corners with two equivalent Ti(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, and edges with four equivalent Ti(4)O6 octahedra. The Mg(5)-O(14) bond length is 2.16 Å. The Mg(5)-O(6) bond length is 2.12 Å. Both Mg(5)-O(12) bond lengths are 2.10 Å. Both Mg(5)-O(4) bond lengths are 2.08 Å. In the sixth Mg site, Mg(6) is bonded to one O(13), one O(18), two equivalent O(10), and two equivalent O(17) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Ti(8)O4 tetrahedra, corners with two equivalent Ti(5)O4 tetrahedra, corners with two equivalent Ti(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, and edges with four equivalent Ti(6)O6 octahedra. The Mg(6)-O(13) bond length is 2.05 Å. The Mg(6)-O(18) bond length is 2.16 Å. Both Mg(6)-O(10) bond lengths are 2.08 Å. Both Mg(6)-O(17) bond lengths are 2.11 Å. There are nine inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form TiO6 octahedra that share  a cornercorner with one Ti(2)O4 tetrahedra,  a cornercorner with one Ti(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Ti(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The Ti(1)-O(1) bond length is 1.98 Å. The Ti(1)-O(2) bond length is 2.07 Å. The Ti(1)-O(3) bond length is 2.02 Å. The Ti(1)-O(5) bond length is 2.19 Å. The Ti(1)-O(7) bond length is 2.14 Å. The Ti(1)-O(8) bond length is 2.12 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(9), and two equivalent O(4) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-59°. The Ti(2)-O(2) bond length is 1.91 Å. The Ti(2)-O(9) bond length is 1.93 Å. Both Ti(2)-O(4) bond lengths are 1.90 Å. In the third Ti site, Ti(3) is bonded to one O(16), one O(3), two equivalent O(1), and two equivalent O(17) atoms to form TiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Ti(9)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with two equivalent Ti(6)O6 octahedra. The Ti(3)-O(16) bond length is 2.10 Å. The Ti(3)-O(3) bond length is 2.16 Å. Both Ti(3)-O(1) bond lengths are 2.08 Å. Both Ti(3)-O(17) bond lengths are 2.07 Å. In the fourth Ti site, Ti(4) is bonded to one O(11), one O(12), one O(14), one O(4), one O(6), and one O(9) atom to form TiO6 octahedra that share  a cornercorner with one Ti(5)O4 tetrahedra,  a cornercorner with one Ti(7)O4 tetrahedra, corners with two equivalent Ti(2)O4 tetrahedra, corners with two equivalent Ti(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Ti(4)O6 octahedra. The Ti(4)-O(11) bond length is 2.07 Å. The Ti(4)-O(12) bond length is 2.06 Å. The Ti(4)-O(14) bond length is 2.09 Å. The Ti(4)-O(4) bond length is 2.07 Å. The Ti(4)-O(6) bond length is 2.18 Å. The Ti(4)-O(9) bond length is 2.15 Å. In the fifth Ti site, Ti(5) is bonded to one O(15), one O(6), and two equivalent O(10) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Ti(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-58°. The Ti(5)-O(15) bond length is 1.89 Å. The Ti(5)-O(6) bond length is 1.91 Å. Both Ti(5)-O(10) bond lengths are 1.88 Å. In the sixth Ti site, Ti(6) is bonded to one O(10), one O(13), one O(15), one O(16), one O(17), and one O(18) atom to form TiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Ti(8)O4 tetrahedra, corners with two equivalent Ti(5)O4 tetrahedra, corners with two equivalent Ti(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, and edges with two equivalent Ti(6)O6 octahedra. The Ti(6)-O(10) bond length is 2.16 Å. The Ti(6)-O(13) bond length is 2.05 Å. The Ti(6)-O(15) bond length is 2.23 Å. The Ti(6)-O(16) bond length is 2.10 Å. The Ti(6)-O(17) bond length is 2.04 Å. The Ti(6)-O(18) bond length is 2.07 Å. In the seventh Ti site, Ti(7) is bonded to one O(14), one O(5), and two equivalent O(7) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-60°. The Ti(7)-O(14) bond length is 1.91 Å. The Ti(7)-O(5) bond length is 1.91 Å. Both Ti(7)-O(7) bond lengths are 1.89 Å. In the eighth Ti site, Ti(8) is bonded to one O(11), one O(18), and two equivalent O(12) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Ti(6)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-59°. The Ti(8)-O(11) bond length is 1.92 Å. The Ti(8)-O(18) bond length is 1.92 Å. Both Ti(8)-O(12) bond lengths are 1.90 Å. In the ninth Ti site, Ti(9) is bonded to one O(16), one O(8), and two equivalent O(17) atoms to form TiO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra, and corners with four equivalent Ti(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-61°. The Ti(9)-O(16) bond length is 1.86 Å. The Ti(9)-O(8) bond length is 1.88 Å. Both Ti(9)-O(17) bond lengths are 1.89 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(3), one Ti(1), and one Ti(3) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Ti(2), and two equivalent Ti(1) atoms. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Ti(3), and two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded to one Mg(2), one Mg(5), one Ti(2), and one Ti(4) atom to form a mixture of distorted corner and edge-sharing OMg2Ti2 trigonal pyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Ti(7), and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mg(5), one Ti(5), and two equivalent Ti(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Ti(1), and one Ti(7) atom. In the eighth O site, O(8) is bonded in a distorted tetrahedral geometry to one Mg(3), one Ti(9), and two equivalent Ti(1) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Mg(2), one Ti(2), and two equivalent Ti(4) atoms. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(6), one Ti(5), and one Ti(6) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Ti(8), and two equivalent Ti(4) atoms. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(5), one Ti(4), and one Ti(8) atom. In the thirteenth O site, O(13) is bonded in a tetrahedral geometry to one Mg(1), one Mg(6), and two equivalent Ti(6) atoms. In the fourteenth O site, O(14) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Ti(7), and two equivalent Ti(4) atoms. In the fifteenth O site, O(15) is bonded in a distorted rectangular see-saw-like geometry to one Mg(4), one Ti(5), and two equivalent Ti(6) atoms. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Ti(3), one Ti(9), and two equivalent Ti(6) atoms. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Ti(3), one Ti(6), and one Ti(9) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Ti(8), and two equivalent Ti(6) atoms.