MgTi4(CuO4)3 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 6-coordinate geometry to one O(6), one O(7), two equivalent O(2), and two equivalent O(5) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(8) atom to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 36-45°. 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(7) atom to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 36-45°. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to one O(3), one O(6), one O(7), and one O(8) atom. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to two equivalent O(4) and two equivalent O(5) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ti(1), one Ti(2), and one Cu(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Cu(2) atom to form a mixture of distorted edge and corner-sharing OMgTi2Cu tetrahedra. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Ti(2) and one Cu(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ti(1), one Ti(2), and one Cu(3) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Cu(3) atom to form a mixture of distorted edge and corner-sharing OMgTi2Cu tetrahedra. In the sixth O site, O(6) is bonded to one Mg(1), two equivalent Ti(1), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing OMgTi2Cu trigonal pyramids. In the seventh O site, O(7) is bonded to one Mg(1), two equivalent Ti(2), and one Cu(1) atom to form edge-sharing OMgTi2Cu tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one Cu(1) atom.
MgTi4(CuO4)3 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 6-coordinate geometry to one O(6), one O(7), two equivalent O(2), and two equivalent O(5) atoms. The Mg(1)-O(6) bond length is 2.52 Å. The Mg(1)-O(7) bond length is 2.07 Å. Both Mg(1)-O(2) bond lengths are 2.19 Å. Both Mg(1)-O(5) bond lengths are 2.44 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(8) atom to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 36-45°. The Ti(1)-O(1) bond length is 2.02 Å. The Ti(1)-O(2) bond length is 1.96 Å. The Ti(1)-O(4) bond length is 2.06 Å. The Ti(1)-O(5) bond length is 1.91 Å. The Ti(1)-O(6) bond length is 1.98 Å. The Ti(1)-O(8) bond length is 1.97 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(7) atom to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 36-45°. The Ti(2)-O(1) bond length is 1.88 Å. The Ti(2)-O(2) bond length is 2.10 Å. The Ti(2)-O(3) bond length is 1.93 Å. The Ti(2)-O(4) bond length is 1.88 Å. The Ti(2)-O(5) bond length is 2.11 Å. The Ti(2)-O(7) bond length is 2.03 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to one O(3), one O(6), one O(7), and one O(8) atom. The Cu(1)-O(3) bond length is 1.96 Å. The Cu(1)-O(6) bond length is 1.99 Å. The Cu(1)-O(7) bond length is 1.96 Å. The Cu(1)-O(8) bond length is 1.99 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Cu(2)-O(1) bond lengths are 1.97 Å. Both Cu(2)-O(2) bond lengths are 1.97 Å. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to two equivalent O(4) and two equivalent O(5) atoms. Both Cu(3)-O(4) bond lengths are 1.97 Å. Both Cu(3)-O(5) bond lengths are 1.98 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ti(1), one Ti(2), and one Cu(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Cu(2) atom to form a mixture of distorted edge and corner-sharing OMgTi2Cu tetrahedra. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Ti(2) and one Cu(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ti(1), one Ti(2), and one Cu(3) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Cu(3) atom to form a mixture of distorted edge and corner-sharing OMgTi2Cu tetrahedra. In the sixth O site, O(6) is bonded to one Mg(1), two equivalent Ti(1), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing OMgTi2Cu trigonal pyramids. In the seventh O site, O(7) is bonded to one Mg(1), two equivalent Ti(2), and one Cu(1) atom to form edge-sharing OMgTi2Cu tetrahedra. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to two equivalent Ti(1) and one Cu(1) atom.