MgTi3Nb(CuO4)3 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one Cu(1), one O(1), one O(10), one O(4), one O(6), and one O(9) atom. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(8) atom to form distorted TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-38°. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(12), one O(3), one O(5), and one O(9) atom. In the third Ti site, Ti(3) is bonded to one O(10), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-42°. Nb(1) is bonded to one O(11), one O(2), one O(5), one O(6), one O(7), and one O(9) atom to form NbO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-42°. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to one Mg(1), one O(12), one O(3), one O(5), one O(7), and one O(8) atom. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(10), one O(11), one O(2), and one O(3) atom. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to one O(1), one O(12), one O(6), and one O(7) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Cu(3) atom to form distorted OMgTi2Cu trigonal pyramids that share  a cornercorner with one O(7)TiNbCu2 tetrahedra, corners with three equivalent O(12)Ti2Cu2 trigonal pyramids, and  an edgeedge with one O(6)MgTiNbCu trigonal pyramid. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ti(1), one Nb(1), and one Cu(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(3), one Cu(1), and one Cu(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Ti(1), and one Ti(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ti(2), one Nb(1), and one Cu(1) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Ti(3), one Nb(1), and one Cu(3) atom to form OMgTiNbCu trigonal pyramids that share corners with three equivalent O(7)TiNbCu2 tetrahedra,  a cornercorner with one O(12)Ti2Cu2 trigonal pyramid, and  an edgeedge with one O(1)MgTi2Cu trigonal pyramid. In the seventh O site, O(7) is bonded to one Ti(3), one Nb(1), one Cu(1), and one Cu(3) atom to form distorted OTiNbCu2 tetrahedra that share  a cornercorner with one O(1)MgTi2Cu trigonal pyramid, corners with three equivalent O(6)MgTiNbCu trigonal pyramids, and  an edgeedge with one O(12)Ti2Cu2 trigonal pyramid. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ti(1), one Ti(3), and one Cu(1) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Mg(1), one Ti(2), and one Nb(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(2), one Ti(3), and one Cu(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Ti(1), one Nb(1), and one Cu(2) atom. In the twelfth O site, O(12) is bonded to one Ti(1), one Ti(2), one Cu(1), and one Cu(3) atom to form OTi2Cu2 trigonal pyramids that share  a cornercorner with one O(6)MgTiNbCu trigonal pyramid, corners with three equivalent O(1)MgTi2Cu trigonal pyramids, and  an edgeedge with one O(7)TiNbCu2 tetrahedra.
MgTi3Nb(CuO4)3 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one Cu(1), one O(1), one O(10), one O(4), one O(6), and one O(9) atom. The Mg(1)-Cu(1) bond length is 2.35 Å. The Mg(1)-O(1) bond length is 2.01 Å. The Mg(1)-O(10) bond length is 2.34 Å. The Mg(1)-O(4) bond length is 2.03 Å. The Mg(1)-O(6) bond length is 2.04 Å. The Mg(1)-O(9) bond length is 2.02 Å. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(8) atom to form distorted TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-38°. The Ti(1)-O(1) bond length is 1.94 Å. The Ti(1)-O(11) bond length is 1.84 Å. The Ti(1)-O(12) bond length is 2.15 Å. The Ti(1)-O(2) bond length is 2.38 Å. The Ti(1)-O(4) bond length is 1.88 Å. The Ti(1)-O(8) bond length is 2.11 Å. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(12), one O(3), one O(5), and one O(9) atom. The Ti(2)-O(1) bond length is 2.20 Å. The Ti(2)-O(10) bond length is 1.81 Å. The Ti(2)-O(12) bond length is 1.94 Å. The Ti(2)-O(3) bond length is 2.39 Å. The Ti(2)-O(5) bond length is 2.02 Å. The Ti(2)-O(9) bond length is 1.92 Å. In the third Ti site, Ti(3) is bonded to one O(10), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-42°. The Ti(3)-O(10) bond length is 2.30 Å. The Ti(3)-O(3) bond length is 1.84 Å. The Ti(3)-O(4) bond length is 2.02 Å. The Ti(3)-O(6) bond length is 1.94 Å. The Ti(3)-O(7) bond length is 2.15 Å. The Ti(3)-O(8) bond length is 1.95 Å. Nb(1) is bonded to one O(11), one O(2), one O(5), one O(6), one O(7), and one O(9) atom to form NbO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-42°. The Nb(1)-O(11) bond length is 2.27 Å. The Nb(1)-O(2) bond length is 1.89 Å. The Nb(1)-O(5) bond length is 1.98 Å. The Nb(1)-O(6) bond length is 2.17 Å. The Nb(1)-O(7) bond length is 1.98 Å. The Nb(1)-O(9) bond length is 2.01 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to one Mg(1), one O(12), one O(3), one O(5), one O(7), and one O(8) atom. The Cu(1)-O(12) bond length is 1.99 Å. The Cu(1)-O(3) bond length is 2.20 Å. The Cu(1)-O(5) bond length is 2.00 Å. The Cu(1)-O(7) bond length is 2.09 Å. The Cu(1)-O(8) bond length is 1.97 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(10), one O(11), one O(2), and one O(3) atom. The Cu(2)-O(10) bond length is 2.18 Å. The Cu(2)-O(11) bond length is 1.94 Å. The Cu(2)-O(2) bond length is 1.95 Å. The Cu(2)-O(3) bond length is 2.05 Å. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to one O(1), one O(12), one O(6), and one O(7) atom. The Cu(3)-O(1) bond length is 2.02 Å. The Cu(3)-O(12) bond length is 2.04 Å. The Cu(3)-O(6) bond length is 2.01 Å. The Cu(3)-O(7) bond length is 2.01 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ti(1), one Ti(2), and one Cu(3) atom to form distorted OMgTi2Cu trigonal pyramids that share  a cornercorner with one O(7)TiNbCu2 tetrahedra, corners with three equivalent O(12)Ti2Cu2 trigonal pyramids, and  an edgeedge with one O(6)MgTiNbCu trigonal pyramid. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ti(1), one Nb(1), and one Cu(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(3), one Cu(1), and one Cu(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Ti(1), and one Ti(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ti(2), one Nb(1), and one Cu(1) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Ti(3), one Nb(1), and one Cu(3) atom to form OMgTiNbCu trigonal pyramids that share corners with three equivalent O(7)TiNbCu2 tetrahedra,  a cornercorner with one O(12)Ti2Cu2 trigonal pyramid, and  an edgeedge with one O(1)MgTi2Cu trigonal pyramid. In the seventh O site, O(7) is bonded to one Ti(3), one Nb(1), one Cu(1), and one Cu(3) atom to form distorted OTiNbCu2 tetrahedra that share  a cornercorner with one O(1)MgTi2Cu trigonal pyramid, corners with three equivalent O(6)MgTiNbCu trigonal pyramids, and  an edgeedge with one O(12)Ti2Cu2 trigonal pyramid. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ti(1), one Ti(3), and one Cu(1) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Mg(1), one Ti(2), and one Nb(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Mg(1), one Ti(2), one Ti(3), and one Cu(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Ti(1), one Nb(1), and one Cu(2) atom. In the twelfth O site, O(12) is bonded to one Ti(1), one Ti(2), one Cu(1), and one Cu(3) atom to form OTi2Cu2 trigonal pyramids that share  a cornercorner with one O(6)MgTiNbCu trigonal pyramid, corners with three equivalent O(1)MgTi2Cu trigonal pyramids, and  an edgeedge with one O(7)TiNbCu2 tetrahedra.