MgNd4Ti4Ta4O24 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(13), one O(2), one O(20), one O(22), one O(5), and one O(8) atom. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to one O(1), one O(11), one O(13), one O(17), one O(19), one O(21), one O(23), and one O(5) 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 27-44°. 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 29-44°. 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 distorted 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 23-45°. 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 29-52°. 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 29-52°. 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 23-44°. 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 29-44°. 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 27-45°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Nd(1), one Ti(1), and one Ta(4) atom. In the second O site, O(2) is bonded to one Mg(1), one Nd(2), one Ti(4), and one Ta(1) atom to form distorted ONdMgTaTi tetrahedra that share  a cornercorner with one O(20)Nd2MgTaTi trigonal bipyramid,  a cornercorner with one O(22)Nd2MgTaTi trigonal bipyramid, corners with two equivalent O(11)NdMgTaTi trigonal pyramids,  an edgeedge with one O(18)Nd2TaTi tetrahedra,  an edgeedge with one O(24)Nd2TaTi tetrahedra,  an edgeedge with one O(20)Nd2MgTaTi trigonal bipyramid, and  an edgeedge with one O(22)Nd2MgTaTi trigonal bipyramid. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar 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 4-coordinate geometry to one Mg(1), one Nd(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 4-coordinate geometry to one Mg(1), 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 to one Mg(1), one Nd(1), one Ti(4), and one Ta(3) atom to form distorted ONdMgTaTi trigonal pyramids that share  a cornercorner with one O(24)Nd2TaTi tetrahedra, corners with two equivalent O(2)NdMgTaTi tetrahedra,  a cornercorner with one O(22)Nd2MgTaTi trigonal bipyramid,  a cornercorner with one O(19)Nd2TaTi trigonal pyramid,  a cornercorner with one O(23)Nd2TaTi trigonal pyramid, corners with two equivalent O(17)Nd2TaTi trigonal pyramids,  an edgeedge with one O(21)Nd2TaTi tetrahedra, and  an edgeedge with one O(20)Nd2MgTaTi trigonal bipyramid. 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 distorted rectangular see-saw-like 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 distorted T-shaped 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 distorted ONd2TaTi trigonal pyramids that share corners with two equivalent O(19)Nd2TaTi trigonal pyramids, corners with two equivalent O(23)Nd2TaTi trigonal pyramids, corners with two equivalent O(11)NdMgTaTi trigonal pyramids, and edges with two equivalent O(21)Nd2TaTi tetrahedra. 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 distorted ONd2TaTi tetrahedra that share corners with two equivalent O(24)Nd2TaTi tetrahedra, corners with two equivalent O(20)Nd2MgTaTi trigonal bipyramids,  an edgeedge with one O(2)NdMgTaTi tetrahedra, and edges with two equivalent O(22)Nd2MgTaTi trigonal bipyramids. 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 distorted ONd2TaTi trigonal pyramids that share corners with two equivalent O(21)Nd2TaTi tetrahedra,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid, corners with two equivalent O(17)Nd2TaTi trigonal pyramids, and edges with two equivalent O(23)Nd2TaTi trigonal pyramids. In the twentieth O site, O(20) is bonded to one Mg(1), one Nd(2), one Nd(4), one Ti(4), and one Ta(2) atom to form distorted ONd2MgTaTi trigonal bipyramids that share  a cornercorner with one O(2)NdMgTaTi tetrahedra, corners with two equivalent O(18)Nd2TaTi tetrahedra,  a cornercorner with one O(22)Nd2MgTaTi trigonal bipyramid,  an edgeedge with one O(2)NdMgTaTi tetrahedra, edges with two equivalent O(24)Nd2TaTi tetrahedra,  an edgeedge with one O(22)Nd2MgTaTi trigonal bipyramid, and  an edgeedge with one O(11)NdMgTaTi trigonal pyramid. 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 distorted ONd2TaTi tetrahedra that share corners with two equivalent O(19)Nd2TaTi trigonal pyramids, corners with two equivalent O(23)Nd2TaTi trigonal pyramids,  an edgeedge with one O(11)NdMgTaTi trigonal pyramid, and edges with two equivalent O(17)Nd2TaTi trigonal pyramids. In the twenty-second O site, O(22) is bonded to one Mg(1), one Nd(2), one Nd(4), one Ti(3), and one Ta(1) atom to form distorted ONd2MgTaTi trigonal bipyramids that share  a cornercorner with one O(2)NdMgTaTi tetrahedra, corners with two equivalent O(24)Nd2TaTi tetrahedra,  a cornercorner with one O(20)Nd2MgTaTi trigonal bipyramid,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid,  an edgeedge with one O(2)NdMgTaTi tetrahedra, edges with two equivalent O(18)Nd2TaTi tetrahedra, and  an edgeedge with one O(20)Nd2MgTaTi trigonal bipyramid. 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 distorted ONd2TaTi trigonal pyramids that share corners with two equivalent O(21)Nd2TaTi tetrahedra,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid, corners with two equivalent O(17)Nd2TaTi trigonal pyramids, and edges with two equivalent O(19)Nd2TaTi 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 distorted ONd2TaTi tetrahedra that share corners with two equivalent O(18)Nd2TaTi tetrahedra, corners with two equivalent O(22)Nd2MgTaTi trigonal bipyramids,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid,  an edgeedge with one O(2)NdMgTaTi tetrahedra, and edges with two equivalent O(20)Nd2MgTaTi trigonal bipyramids.
MgNd4Ti4Ta4O24 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(13), one O(2), one O(20), one O(22), one O(5), and one O(8) atom. The Mg(1)-O(10) bond length is 2.68 Å. The Mg(1)-O(11) bond length is 2.24 Å. The Mg(1)-O(13) bond length is 2.06 Å. The Mg(1)-O(2) bond length is 2.15 Å. The Mg(1)-O(20) bond length is 2.49 Å. The Mg(1)-O(22) bond length is 2.26 Å. The Mg(1)-O(5) bond length is 2.19 Å. The Mg(1)-O(8) bond length is 2.56 Å. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to one O(1), one O(11), one O(13), one O(17), one O(19), one O(21), one O(23), and one O(5) atom. The Nd(1)-O(1) bond length is 2.48 Å. The Nd(1)-O(11) bond length is 2.61 Å. The Nd(1)-O(13) bond length is 2.43 Å. The Nd(1)-O(17) bond length is 2.50 Å. The Nd(1)-O(19) bond length is 2.43 Å. The Nd(1)-O(21) bond length is 2.45 Å. The Nd(1)-O(23) bond length is 2.49 Å. The Nd(1)-O(5) bond length is 2.56 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 2.40 Å. The Nd(2)-O(14) bond length is 2.37 Å. The Nd(2)-O(18) bond length is 2.52 Å. The Nd(2)-O(2) bond length is 2.44 Å. The Nd(2)-O(20) bond length is 2.53 Å. The Nd(2)-O(22) bond length is 2.53 Å. The Nd(2)-O(24) bond length is 2.55 Å. The Nd(2)-O(6) bond length is 2.42 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 2.42 Å. The Nd(3)-O(17) bond length is 2.44 Å. The Nd(3)-O(19) bond length is 2.53 Å. The Nd(3)-O(21) bond length is 2.51 Å. The Nd(3)-O(23) bond length is 2.45 Å. The Nd(3)-O(3) bond length is 2.46 Å. The Nd(3)-O(7) bond length is 2.50 Å. The Nd(3)-O(9) bond length is 2.51 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 2.49 Å. The Nd(4)-O(16) bond length is 2.47 Å. The Nd(4)-O(18) bond length is 2.52 Å. The Nd(4)-O(20) bond length is 2.55 Å. The Nd(4)-O(22) bond length is 2.62 Å. The Nd(4)-O(24) bond length is 2.49 Å. The Nd(4)-O(4) bond length is 2.39 Å. The Nd(4)-O(8) bond length is 2.56 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 27-44°. The Ti(1)-O(1) bond length is 1.97 Å. The Ti(1)-O(15) bond length is 2.00 Å. The Ti(1)-O(17) bond length is 2.20 Å. The Ti(1)-O(21) bond length is 2.03 Å. The Ti(1)-O(6) bond length is 1.89 Å. The Ti(1)-O(7) bond length is 2.01 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 29-44°. The Ti(2)-O(13) bond length is 2.08 Å. The Ti(2)-O(19) bond length is 2.08 Å. The Ti(2)-O(23) bond length is 1.95 Å. The Ti(2)-O(3) bond length is 1.93 Å. The Ti(2)-O(5) bond length is 2.08 Å. The Ti(2)-O(8) bond length is 1.96 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 distorted 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 23-45°. The Ti(3)-O(12) bond length is 2.00 Å. The Ti(3)-O(14) bond length is 2.00 Å. The Ti(3)-O(18) bond length is 2.00 Å. The Ti(3)-O(22) bond length is 2.43 Å. The Ti(3)-O(4) bond length is 1.98 Å. The Ti(3)-O(9) bond length is 1.86 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 29-52°. The Ti(4)-O(10) bond length is 2.01 Å. The Ti(4)-O(11) bond length is 1.97 Å. The Ti(4)-O(16) bond length is 2.02 Å. The Ti(4)-O(2) bond length is 2.08 Å. The Ti(4)-O(20) bond length is 2.06 Å. The Ti(4)-O(24) bond length is 2.07 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 29-52°. The Ta(1)-O(16) bond length is 1.97 Å. The Ta(1)-O(18) bond length is 2.07 Å. The Ta(1)-O(2) bond length is 2.08 Å. The Ta(1)-O(22) bond length is 2.05 Å. The Ta(1)-O(5) bond length is 1.97 Å. The Ta(1)-O(8) bond length is 1.99 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 23-44°. The Ta(2)-O(14) bond length is 2.02 Å. The Ta(2)-O(20) bond length is 2.22 Å. The Ta(2)-O(24) bond length is 2.01 Å. The Ta(2)-O(4) bond length is 1.98 Å. The Ta(2)-O(6) bond length is 2.01 Å. The Ta(2)-O(7) bond length is 1.91 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 29-44°. The Ta(3)-O(10) bond length is 1.94 Å. The Ta(3)-O(11) bond length is 2.05 Å. The Ta(3)-O(13) bond length is 2.09 Å. The Ta(3)-O(17) bond length is 1.97 Å. The Ta(3)-O(21) bond length is 2.08 Å. The Ta(3)-O(3) bond length is 1.94 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 27-45°. The Ta(4)-O(1) bond length is 1.98 Å. The Ta(4)-O(12) bond length is 1.92 Å. The Ta(4)-O(15) bond length is 2.00 Å. The Ta(4)-O(19) bond length is 2.01 Å. The Ta(4)-O(23) bond length is 2.16 Å. The Ta(4)-O(9) bond length is 2.02 Å. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Nd(1), one Ti(1), and one Ta(4) atom. In the second O site, O(2) is bonded to one Mg(1), one Nd(2), one Ti(4), and one Ta(1) atom to form distorted ONdMgTaTi tetrahedra that share  a cornercorner with one O(20)Nd2MgTaTi trigonal bipyramid,  a cornercorner with one O(22)Nd2MgTaTi trigonal bipyramid, corners with two equivalent O(11)NdMgTaTi trigonal pyramids,  an edgeedge with one O(18)Nd2TaTi tetrahedra,  an edgeedge with one O(24)Nd2TaTi tetrahedra,  an edgeedge with one O(20)Nd2MgTaTi trigonal bipyramid, and  an edgeedge with one O(22)Nd2MgTaTi trigonal bipyramid. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar 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 4-coordinate geometry to one Mg(1), one Nd(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 4-coordinate geometry to one Mg(1), 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 to one Mg(1), one Nd(1), one Ti(4), and one Ta(3) atom to form distorted ONdMgTaTi trigonal pyramids that share  a cornercorner with one O(24)Nd2TaTi tetrahedra, corners with two equivalent O(2)NdMgTaTi tetrahedra,  a cornercorner with one O(22)Nd2MgTaTi trigonal bipyramid,  a cornercorner with one O(19)Nd2TaTi trigonal pyramid,  a cornercorner with one O(23)Nd2TaTi trigonal pyramid, corners with two equivalent O(17)Nd2TaTi trigonal pyramids,  an edgeedge with one O(21)Nd2TaTi tetrahedra, and  an edgeedge with one O(20)Nd2MgTaTi trigonal bipyramid. 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 distorted rectangular see-saw-like 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 distorted T-shaped 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 distorted ONd2TaTi trigonal pyramids that share corners with two equivalent O(19)Nd2TaTi trigonal pyramids, corners with two equivalent O(23)Nd2TaTi trigonal pyramids, corners with two equivalent O(11)NdMgTaTi trigonal pyramids, and edges with two equivalent O(21)Nd2TaTi tetrahedra. 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 distorted ONd2TaTi tetrahedra that share corners with two equivalent O(24)Nd2TaTi tetrahedra, corners with two equivalent O(20)Nd2MgTaTi trigonal bipyramids,  an edgeedge with one O(2)NdMgTaTi tetrahedra, and edges with two equivalent O(22)Nd2MgTaTi trigonal bipyramids. 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 distorted ONd2TaTi trigonal pyramids that share corners with two equivalent O(21)Nd2TaTi tetrahedra,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid, corners with two equivalent O(17)Nd2TaTi trigonal pyramids, and edges with two equivalent O(23)Nd2TaTi trigonal pyramids. In the twentieth O site, O(20) is bonded to one Mg(1), one Nd(2), one Nd(4), one Ti(4), and one Ta(2) atom to form distorted ONd2MgTaTi trigonal bipyramids that share  a cornercorner with one O(2)NdMgTaTi tetrahedra, corners with two equivalent O(18)Nd2TaTi tetrahedra,  a cornercorner with one O(22)Nd2MgTaTi trigonal bipyramid,  an edgeedge with one O(2)NdMgTaTi tetrahedra, edges with two equivalent O(24)Nd2TaTi tetrahedra,  an edgeedge with one O(22)Nd2MgTaTi trigonal bipyramid, and  an edgeedge with one O(11)NdMgTaTi trigonal pyramid. 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 distorted ONd2TaTi tetrahedra that share corners with two equivalent O(19)Nd2TaTi trigonal pyramids, corners with two equivalent O(23)Nd2TaTi trigonal pyramids,  an edgeedge with one O(11)NdMgTaTi trigonal pyramid, and edges with two equivalent O(17)Nd2TaTi trigonal pyramids. In the twenty-second O site, O(22) is bonded to one Mg(1), one Nd(2), one Nd(4), one Ti(3), and one Ta(1) atom to form distorted ONd2MgTaTi trigonal bipyramids that share  a cornercorner with one O(2)NdMgTaTi tetrahedra, corners with two equivalent O(24)Nd2TaTi tetrahedra,  a cornercorner with one O(20)Nd2MgTaTi trigonal bipyramid,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid,  an edgeedge with one O(2)NdMgTaTi tetrahedra, edges with two equivalent O(18)Nd2TaTi tetrahedra, and  an edgeedge with one O(20)Nd2MgTaTi trigonal bipyramid. 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 distorted ONd2TaTi trigonal pyramids that share corners with two equivalent O(21)Nd2TaTi tetrahedra,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid, corners with two equivalent O(17)Nd2TaTi trigonal pyramids, and edges with two equivalent O(19)Nd2TaTi 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 distorted ONd2TaTi tetrahedra that share corners with two equivalent O(18)Nd2TaTi tetrahedra, corners with two equivalent O(22)Nd2MgTaTi trigonal bipyramids,  a cornercorner with one O(11)NdMgTaTi trigonal pyramid,  an edgeedge with one O(2)NdMgTaTi tetrahedra, and edges with two equivalent O(20)Nd2MgTaTi trigonal bipyramids.