Gd3TaO7 crystallizes in the triclinic P-1 space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(3), one O(4), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O6 octahedra, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 49-51°. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(6), two equivalent O(4), and two equivalent O(7) atoms. In the third Gd site, Gd(3) is bonded to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 44°. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form TaO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Gd(1)O7 pentagonal bipyramids, corners with two equivalent Gd(3)O7 pentagonal bipyramids, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. In the second Ta site, Ta(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Gd(1)O7 pentagonal bipyramids, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Gd(2), two equivalent Gd(3), and one Ta(2) atom to form distorted OGd3Ta trigonal pyramids that share  a cornercorner with one O(6)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Ta tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(3)Gd3Ta tetrahedra,  a cornercorner with one O(1)Gd3Ta trigonal pyramid,  an edgeedge with one O(4)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Gd(2), two equivalent Gd(1), and one Ta(1) atom. In the third O site, O(3) is bonded to one Gd(1), two equivalent Gd(3), and one Ta(1) atom to form distorted OGd3Ta tetrahedra that share  a cornercorner with one O(3)Gd3Ta tetrahedra,  a cornercorner with one O(4)Gd3Ta tetrahedra,  a cornercorner with one O(7)Gd4 tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra, corners with four equivalent O(1)Gd3Ta trigonal pyramids,  an edgeedge with one O(3)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra, and  an edgeedge with one O(7)Gd4 tetrahedra. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one Ta(2) atom to form distorted OGd3Ta tetrahedra that share  a cornercorner with one O(3)Gd3Ta tetrahedra,  a cornercorner with one O(4)Gd3Ta tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(1)Gd3Ta trigonal pyramids,  an edgeedge with one O(4)Gd3Ta tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Gd(3), one Ta(1), and one Ta(2) atom. In the sixth O site, O(6) is bonded to one Gd(2), one Gd(3), and two equivalent Gd(1) atoms to form OGd4 tetrahedra that share corners with two equivalent O(3)Gd3Ta tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Ta tetrahedra,  a cornercorner with one O(1)Gd3Ta trigonal pyramid,  an edgeedge with one O(3)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid. In the seventh O site, O(7) is bonded to one Gd(1), one Gd(3), and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share  a cornercorner with one O(3)Gd3Ta tetrahedra, corners with three equivalent O(4)Gd3Ta tetrahedra, corners with three equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(1)Gd3Ta trigonal pyramids,  an edgeedge with one O(3)Gd3Ta tetrahedra,  an edgeedge with one O(4)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid.
Gd3TaO7 crystallizes in the triclinic P-1 space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(3), one O(4), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Gd(3)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O6 octahedra, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 49-51°. The Gd(1)-O(3) bond length is 2.46 Å. The Gd(1)-O(4) bond length is 2.40 Å. The Gd(1)-O(7) bond length is 2.32 Å. There is one shorter (2.39 Å) and one longer (2.48 Å) Gd(1)-O(2) bond length. There is one shorter (2.32 Å) and one longer (2.36 Å) Gd(1)-O(6) bond length. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(6), two equivalent O(4), and two equivalent O(7) atoms. The Gd(2)-O(1) bond length is 2.44 Å. The Gd(2)-O(2) bond length is 2.70 Å. The Gd(2)-O(6) bond length is 2.30 Å. There is one shorter (2.44 Å) and one longer (2.61 Å) Gd(2)-O(4) bond length. There is one shorter (2.24 Å) and one longer (2.30 Å) Gd(2)-O(7) bond length. In the third Gd site, Gd(3) is bonded to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Gd(1)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 44°. The Gd(3)-O(5) bond length is 2.44 Å. The Gd(3)-O(6) bond length is 2.22 Å. The Gd(3)-O(7) bond length is 2.22 Å. There is one shorter (2.34 Å) and one longer (2.43 Å) Gd(3)-O(1) bond length. There is one shorter (2.32 Å) and one longer (2.41 Å) Gd(3)-O(3) bond length. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form TaO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Gd(1)O7 pentagonal bipyramids, corners with two equivalent Gd(3)O7 pentagonal bipyramids, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. Both Ta(1)-O(2) bond lengths are 2.01 Å. Both Ta(1)-O(3) bond lengths are 1.98 Å. Both Ta(1)-O(5) bond lengths are 1.99 Å. In the second Ta site, Ta(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Gd(1)O7 pentagonal bipyramids, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. Both Ta(2)-O(1) bond lengths are 1.97 Å. Both Ta(2)-O(4) bond lengths are 2.04 Å. Both Ta(2)-O(5) bond lengths are 1.97 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Gd(2), two equivalent Gd(3), and one Ta(2) atom to form distorted OGd3Ta trigonal pyramids that share  a cornercorner with one O(6)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Ta tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(3)Gd3Ta tetrahedra,  a cornercorner with one O(1)Gd3Ta trigonal pyramid,  an edgeedge with one O(4)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Gd(2), two equivalent Gd(1), and one Ta(1) atom. In the third O site, O(3) is bonded to one Gd(1), two equivalent Gd(3), and one Ta(1) atom to form distorted OGd3Ta tetrahedra that share  a cornercorner with one O(3)Gd3Ta tetrahedra,  a cornercorner with one O(4)Gd3Ta tetrahedra,  a cornercorner with one O(7)Gd4 tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra, corners with four equivalent O(1)Gd3Ta trigonal pyramids,  an edgeedge with one O(3)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra, and  an edgeedge with one O(7)Gd4 tetrahedra. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one Ta(2) atom to form distorted OGd3Ta tetrahedra that share  a cornercorner with one O(3)Gd3Ta tetrahedra,  a cornercorner with one O(4)Gd3Ta tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(1)Gd3Ta trigonal pyramids,  an edgeedge with one O(4)Gd3Ta tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Gd(3), one Ta(1), and one Ta(2) atom. In the sixth O site, O(6) is bonded to one Gd(2), one Gd(3), and two equivalent Gd(1) atoms to form OGd4 tetrahedra that share corners with two equivalent O(3)Gd3Ta tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Ta tetrahedra,  a cornercorner with one O(1)Gd3Ta trigonal pyramid,  an edgeedge with one O(3)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid. In the seventh O site, O(7) is bonded to one Gd(1), one Gd(3), and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share  a cornercorner with one O(3)Gd3Ta tetrahedra, corners with three equivalent O(4)Gd3Ta tetrahedra, corners with three equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(1)Gd3Ta trigonal pyramids,  an edgeedge with one O(3)Gd3Ta tetrahedra,  an edgeedge with one O(4)Gd3Ta tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Ta trigonal pyramid.