MgNd4Ti4Ta4O24 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(10), one O(11), one O(13), one O(2), and one O(5) atom. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to one O(1), one O(13), one O(17), one O(19), one O(21), and one O(23) atom. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one O(12), one O(14), one O(18), one O(2), one O(20), one O(22), one O(24), and one O(6) atom. In the third Nd site, Nd(3) is bonded in a 8-coordinate geometry to one O(15), one O(17), one O(19), one O(21), one O(23), one O(3), one O(7), and one O(9) atom. In the fourth Nd site, Nd(4) is bonded in a 8-coordinate geometry to one O(10), one O(16), one O(18), one O(20), one O(22), one O(24), one O(4), and one O(8) atom. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(15), one O(17), one O(21), one O(6), and one O(7) atom to form TiO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. In the second Ti site, Ti(2) is bonded to one O(13), one O(19), one O(23), one O(3), one O(5), and one O(8) atom to form TiO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and  an edgeedge with one Ta(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-53°. In the third Ti site, Ti(3) is bonded to one O(12), one O(14), one O(18), one O(22), one O(4), and one O(9) atom to form TiO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. In the fourth Ti site, Ti(4) is bonded to one O(10), one O(11), one O(16), one O(2), one O(20), and one O(24) atom to form TiO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and  an edgeedge with one Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-53°. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(16), one O(18), one O(2), one O(22), one O(5), and one O(8) atom to form TaO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and  an edgeedge with one Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-53°. In the second Ta site, Ta(2) is bonded to one O(14), one O(20), one O(24), one O(4), one O(6), and one O(7) atom to form TaO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and  an edgeedge with one Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. In the third Ta site, Ta(3) is bonded to one O(10), one O(11), one O(13), one O(17), one O(21), and one O(3) atom to form TaO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and  an edgeedge with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-53°. In the fourth Ta site, Ta(4) is bonded to one O(1), one O(12), one O(15), one O(19), one O(23), and one O(9) atom to form TaO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and  an edgeedge with one Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nd(1), one Ti(1), and one Ta(4) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(2), one Ti(4), and one Ta(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(2), and one Ta(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Nd(4), one Ti(3), and one Ta(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Ti(2), and one Ta(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Nd(2), one Ti(1), and one Ta(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(1), and one Ta(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Nd(4), one Ti(2), and one Ta(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(3), and one Ta(4) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(4), one Ti(4), and one Ta(3) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Mg(1), one Ti(4), and one Ta(3) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Nd(2), one Ti(3), and one Ta(4) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(1), one Ti(2), and one Ta(3) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Nd(2), one Ti(3), and one Ta(2) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(1), and one Ta(4) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Nd(4), one Ti(4), and one Ta(1) atom. In the seventeenth O site, O(17) is bonded to one Nd(1), one Nd(3), one Ti(1), and one Ta(3) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the eighteenth O site, O(18) is bonded to one Nd(2), one Nd(4), one Ti(3), and one Ta(1) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra. In the nineteenth O site, O(19) is bonded to one Nd(1), one Nd(3), one Ti(2), and one Ta(4) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra. In the twentieth O site, O(20) is bonded to one Nd(2), one Nd(4), one Ti(4), and one Ta(2) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the twenty-first O site, O(21) is bonded to one Nd(1), one Nd(3), one Ti(1), and one Ta(3) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra. In the twenty-second O site, O(22) is bonded to one Nd(2), one Nd(4), one Ti(3), and one Ta(1) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the twenty-third O site, O(23) is bonded to one Nd(1), one Nd(3), one Ti(2), and one Ta(4) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the twenty-fourth O site, O(24) is bonded to one Nd(2), one Nd(4), one Ti(4), and one Ta(2) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra.
MgNd4Ti4Ta4O24 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(10), one O(11), one O(13), one O(2), and one O(5) atom. The Mg(1)-O(10) bond length is 2.30 Å. The Mg(1)-O(11) bond length is 2.01 Å. The Mg(1)-O(13) bond length is 1.89 Å. The Mg(1)-O(2) bond length is 1.89 Å. The Mg(1)-O(5) bond length is 2.17 Å. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to one O(1), one O(13), one O(17), one O(19), one O(21), and one O(23) atom. The Nd(1)-O(1) bond length is 2.24 Å. The Nd(1)-O(13) bond length is 2.55 Å. The Nd(1)-O(17) bond length is 2.54 Å. The Nd(1)-O(19) bond length is 2.36 Å. The Nd(1)-O(21) bond length is 2.38 Å. The Nd(1)-O(23) bond length is 2.55 Å. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one O(12), one O(14), one O(18), one O(2), one O(20), one O(22), one O(24), and one O(6) atom. The Nd(2)-O(12) bond length is 2.47 Å. The Nd(2)-O(14) bond length is 2.46 Å. The Nd(2)-O(18) bond length is 2.53 Å. The Nd(2)-O(2) bond length is 2.40 Å. The Nd(2)-O(20) bond length is 2.47 Å. The Nd(2)-O(22) bond length is 2.50 Å. The Nd(2)-O(24) bond length is 2.59 Å. The Nd(2)-O(6) bond length is 2.50 Å. In the third Nd site, Nd(3) is bonded in a 8-coordinate geometry to one O(15), one O(17), one O(19), one O(21), one O(23), one O(3), one O(7), and one O(9) atom. The Nd(3)-O(15) bond length is 2.43 Å. The Nd(3)-O(17) bond length is 2.41 Å. The Nd(3)-O(19) bond length is 2.48 Å. The Nd(3)-O(21) bond length is 2.49 Å. The Nd(3)-O(23) bond length is 2.41 Å. The Nd(3)-O(3) bond length is 2.58 Å. The Nd(3)-O(7) bond length is 2.57 Å. The Nd(3)-O(9) bond length is 2.61 Å. In the fourth Nd site, Nd(4) is bonded in a 8-coordinate geometry to one O(10), one O(16), one O(18), one O(20), one O(22), one O(24), one O(4), and one O(8) atom. The Nd(4)-O(10) bond length is 2.76 Å. The Nd(4)-O(16) bond length is 2.47 Å. The Nd(4)-O(18) bond length is 2.45 Å. The Nd(4)-O(20) bond length is 2.48 Å. The Nd(4)-O(22) bond length is 2.48 Å. The Nd(4)-O(24) bond length is 2.46 Å. The Nd(4)-O(4) bond length is 2.43 Å. The Nd(4)-O(8) bond length is 2.73 Å. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(15), one O(17), one O(21), one O(6), and one O(7) atom to form TiO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. The Ti(1)-O(1) bond length is 1.99 Å. The Ti(1)-O(15) bond length is 1.98 Å. The Ti(1)-O(17) bond length is 2.15 Å. The Ti(1)-O(21) bond length is 1.97 Å. The Ti(1)-O(6) bond length is 1.93 Å. The Ti(1)-O(7) bond length is 2.02 Å. In the second Ti site, Ti(2) is bonded to one O(13), one O(19), one O(23), one O(3), one O(5), and one O(8) atom to form TiO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and  an edgeedge with one Ta(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-53°. The Ti(2)-O(13) bond length is 2.06 Å. The Ti(2)-O(19) bond length is 2.23 Å. The Ti(2)-O(23) bond length is 1.98 Å. The Ti(2)-O(3) bond length is 1.99 Å. The Ti(2)-O(5) bond length is 2.04 Å. The Ti(2)-O(8) bond length is 1.97 Å. In the third Ti site, Ti(3) is bonded to one O(12), one O(14), one O(18), one O(22), one O(4), and one O(9) atom to form TiO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. The Ti(3)-O(12) bond length is 1.98 Å. The Ti(3)-O(14) bond length is 2.06 Å. The Ti(3)-O(18) bond length is 2.03 Å. The Ti(3)-O(22) bond length is 2.17 Å. The Ti(3)-O(4) bond length is 1.96 Å. The Ti(3)-O(9) bond length is 1.92 Å. In the fourth Ti site, Ti(4) is bonded to one O(10), one O(11), one O(16), one O(2), one O(20), and one O(24) atom to form TiO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and  an edgeedge with one Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-53°. The Ti(4)-O(10) bond length is 2.20 Å. The Ti(4)-O(11) bond length is 2.05 Å. The Ti(4)-O(16) bond length is 1.94 Å. The Ti(4)-O(2) bond length is 2.08 Å. The Ti(4)-O(20) bond length is 1.92 Å. The Ti(4)-O(24) bond length is 2.01 Å. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(16), one O(18), one O(2), one O(22), one O(5), and one O(8) atom to form TaO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and  an edgeedge with one Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-53°. The Ta(1)-O(16) bond length is 1.95 Å. The Ta(1)-O(18) bond length is 2.08 Å. The Ta(1)-O(2) bond length is 2.07 Å. The Ta(1)-O(22) bond length is 1.99 Å. The Ta(1)-O(5) bond length is 1.97 Å. The Ta(1)-O(8) bond length is 2.06 Å. In the second Ta site, Ta(2) is bonded to one O(14), one O(20), one O(24), one O(4), one O(6), and one O(7) atom to form TaO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and  an edgeedge with one Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. The Ta(2)-O(14) bond length is 2.01 Å. The Ta(2)-O(20) bond length is 2.17 Å. The Ta(2)-O(24) bond length is 2.05 Å. The Ta(2)-O(4) bond length is 1.99 Å. The Ta(2)-O(6) bond length is 1.97 Å. The Ta(2)-O(7) bond length is 1.92 Å. In the third Ta site, Ta(3) is bonded to one O(10), one O(11), one O(13), one O(17), one O(21), and one O(3) atom to form TaO6 octahedra that share corners with two equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and  an edgeedge with one Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-53°. The Ta(3)-O(10) bond length is 1.94 Å. The Ta(3)-O(11) bond length is 1.97 Å. The Ta(3)-O(13) bond length is 2.13 Å. The Ta(3)-O(17) bond length is 2.03 Å. The Ta(3)-O(21) bond length is 2.16 Å. The Ta(3)-O(3) bond length is 1.93 Å. In the fourth Ta site, Ta(4) is bonded to one O(1), one O(12), one O(15), one O(19), one O(23), and one O(9) atom to form TaO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and  an edgeedge with one Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-48°. The Ta(4)-O(1) bond length is 2.01 Å. The Ta(4)-O(12) bond length is 1.93 Å. The Ta(4)-O(15) bond length is 1.97 Å. The Ta(4)-O(19) bond length is 1.99 Å. The Ta(4)-O(23) bond length is 2.16 Å. The Ta(4)-O(9) bond length is 2.00 Å. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nd(1), one Ti(1), and one Ta(4) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(2), one Ti(4), and one Ta(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(2), and one Ta(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Nd(4), one Ti(3), and one Ta(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Ti(2), and one Ta(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Nd(2), one Ti(1), and one Ta(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(1), and one Ta(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Nd(4), one Ti(2), and one Ta(1) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(3), and one Ta(4) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(4), one Ti(4), and one Ta(3) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Mg(1), one Ti(4), and one Ta(3) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Nd(2), one Ti(3), and one Ta(4) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Mg(1), one Nd(1), one Ti(2), and one Ta(3) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Nd(2), one Ti(3), and one Ta(2) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Nd(3), one Ti(1), and one Ta(4) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Nd(4), one Ti(4), and one Ta(1) atom. In the seventeenth O site, O(17) is bonded to one Nd(1), one Nd(3), one Ti(1), and one Ta(3) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the eighteenth O site, O(18) is bonded to one Nd(2), one Nd(4), one Ti(3), and one Ta(1) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra. In the nineteenth O site, O(19) is bonded to one Nd(1), one Nd(3), one Ti(2), and one Ta(4) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra. In the twentieth O site, O(20) is bonded to one Nd(2), one Nd(4), one Ti(4), and one Ta(2) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the twenty-first O site, O(21) is bonded to one Nd(1), one Nd(3), one Ti(1), and one Ta(3) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra. In the twenty-second O site, O(22) is bonded to one Nd(2), one Nd(4), one Ti(3), and one Ta(1) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the twenty-third O site, O(23) is bonded to one Nd(1), one Nd(3), one Ti(2), and one Ta(4) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi trigonal pyramids. In the twenty-fourth O site, O(24) is bonded to one Nd(2), one Nd(4), one Ti(4), and one Ta(2) atom to form a mixture of distorted edge and corner-sharing ONd2TaTi tetrahedra.