MgV6O15 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(6), one O(8), and two equivalent O(14) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent V(2)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 68°. There are six inequivalent V sites. In the first V site, V(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(5), one O(9), and two equivalent O(12) atoms. In the second V site, V(2) is bonded to one O(11), one O(14), one O(15), one O(9), and two equivalent O(4) atoms to form distorted VO6 octahedra that share corners with two equivalent V(2)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. In the third V site, V(3) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(13) atoms. In the fourth V site, V(4) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(7), and two equivalent O(15) atoms. In the fifth V site, V(5) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(15), one O(8), and two equivalent O(1) atoms. In the sixth V site, V(6) is bonded in a 5-coordinate geometry to one O(10), one O(11), one O(13), and two equivalent O(3) atoms. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one V(1), one V(4), and two equivalent V(5) atoms. In the second O site, O(2) is bonded in a distorted water-like geometry to one V(1) and one V(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one V(3) and two equivalent V(6) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one V(4) and two equivalent V(2) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one V(1), one V(3), and one V(4) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Mg(1) and one V(3) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one V(4) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Mg(1) and one V(5) atom. In the ninth O site, O(9) is bonded in a linear geometry to one V(1) and one V(2) atom. In the tenth O site, O(10) is bonded in a single-bond geometry to one V(6) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one V(2), one V(5), and one V(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one V(5) and two equivalent V(1) atoms. In the thirteenth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one V(6) and two equivalent V(3) atoms. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one V(2) atom. In the fifteenth O site, O(15) is bonded to one V(2), one V(5), and two equivalent V(4) atoms to form distorted corner-sharing OV4 trigonal pyramids.
MgV6O15 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(6), one O(8), and two equivalent O(14) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent V(2)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 68°. The Mg(1)-O(6) bond length is 1.96 Å. The Mg(1)-O(8) bond length is 2.01 Å. Both Mg(1)-O(14) bond lengths are 2.05 Å. There are six inequivalent V sites. In the first V site, V(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(5), one O(9), and two equivalent O(12) atoms. The V(1)-O(1) bond length is 2.27 Å. The V(1)-O(2) bond length is 1.64 Å. The V(1)-O(5) bond length is 2.13 Å. The V(1)-O(9) bond length is 1.76 Å. Both V(1)-O(12) bond lengths are 1.95 Å. In the second V site, V(2) is bonded to one O(11), one O(14), one O(15), one O(9), and two equivalent O(4) atoms to form distorted VO6 octahedra that share corners with two equivalent V(2)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. The V(2)-O(11) bond length is 2.21 Å. The V(2)-O(14) bond length is 1.80 Å. The V(2)-O(15) bond length is 2.09 Å. The V(2)-O(9) bond length is 1.87 Å. Both V(2)-O(4) bond lengths are 1.91 Å. In the third V site, V(3) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(13) atoms. The V(3)-O(2) bond length is 2.33 Å. The V(3)-O(3) bond length is 2.07 Å. The V(3)-O(5) bond length is 1.98 Å. The V(3)-O(6) bond length is 1.68 Å. Both V(3)-O(13) bond lengths are 1.95 Å. In the fourth V site, V(4) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one O(7), and two equivalent O(15) atoms. The V(4)-O(1) bond length is 2.52 Å. The V(4)-O(4) bond length is 2.03 Å. The V(4)-O(5) bond length is 1.81 Å. The V(4)-O(7) bond length is 1.60 Å. Both V(4)-O(15) bond lengths are 1.96 Å. In the fifth V site, V(5) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(15), one O(8), and two equivalent O(1) atoms. The V(5)-O(11) bond length is 1.86 Å. The V(5)-O(12) bond length is 1.97 Å. The V(5)-O(15) bond length is 2.39 Å. The V(5)-O(8) bond length is 1.66 Å. Both V(5)-O(1) bond lengths are 1.91 Å. In the sixth V site, V(6) is bonded in a 5-coordinate geometry to one O(10), one O(11), one O(13), and two equivalent O(3) atoms. The V(6)-O(10) bond length is 1.60 Å. The V(6)-O(11) bond length is 1.93 Å. The V(6)-O(13) bond length is 1.92 Å. Both V(6)-O(3) bond lengths are 1.94 Å. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one V(1), one V(4), and two equivalent V(5) atoms. In the second O site, O(2) is bonded in a distorted water-like geometry to one V(1) and one V(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one V(3) and two equivalent V(6) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one V(4) and two equivalent V(2) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one V(1), one V(3), and one V(4) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Mg(1) and one V(3) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one V(4) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Mg(1) and one V(5) atom. In the ninth O site, O(9) is bonded in a linear geometry to one V(1) and one V(2) atom. In the tenth O site, O(10) is bonded in a single-bond geometry to one V(6) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one V(2), one V(5), and one V(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one V(5) and two equivalent V(1) atoms. In the thirteenth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one V(6) and two equivalent V(3) atoms. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one V(2) atom. In the fifteenth O site, O(15) is bonded to one V(2), one V(5), and two equivalent V(4) atoms to form distorted corner-sharing OV4 trigonal pyramids.