Gd3SbO7 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 hexagonal pyramids that share  a cornercorner with one Sb(1)O6 octahedra,  a cornercorner with one Sb(2)O6 octahedra,  a cornercorner with one Gd(3)O7 pentagonal bipyramid, edges with two equivalent Gd(1)O7 hexagonal pyramids,  an edgeedge with one Sb(1)O6 octahedra, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-49°. In the second Gd site, Gd(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), 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 Gd(1)O7 hexagonal pyramid,  a cornercorner with one Sb(1)O6 octahedra,  a cornercorner with one Sb(2)O6 octahedra, edges with two equivalent Gd(1)O7 hexagonal pyramids,  an edgeedge with one Sb(1)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 44-45°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form SbO6 octahedra that share corners with two equivalent Gd(1)O7 hexagonal pyramids, corners with two equivalent Sb(2)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, edges with two equivalent Gd(1)O7 hexagonal pyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. In the second Sb site, Sb(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form SbO6 octahedra that share corners with two equivalent Gd(1)O7 hexagonal pyramids, corners with two equivalent Sb(1)O6 octahedra, 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 39°. 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 Sb(2) atom to form distorted OGd3Sb trigonal pyramids that share  a cornercorner with one O(6)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Sb tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra,  a cornercorner with one O(1)Gd3Sb trigonal pyramid, corners with four equivalent O(3)Gd3Sb trigonal pyramids,  an edgeedge with one O(4)Gd3Sb tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Sb 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 Sb(1) atom. In the third O site, O(3) is bonded to one Gd(1), two equivalent Gd(3), and one Sb(1) atom to form distorted OGd3Sb trigonal pyramids that share  a cornercorner with one O(4)Gd3Sb tetrahedra,  a cornercorner with one O(7)Gd4 tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3Sb trigonal pyramid, corners with four equivalent O(1)Gd3Sb trigonal pyramids,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3Sb trigonal pyramid. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one Sb(2) atom to form distorted OGd3Sb tetrahedra that share  a cornercorner with one O(4)Gd3Sb tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3Sb trigonal pyramid, corners with two equivalent O(1)Gd3Sb trigonal pyramids,  an edgeedge with one O(4)Gd3Sb tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Sb trigonal pyramid. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), one Sb(1), and one Sb(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 three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Sb tetrahedra,  a cornercorner with one O(1)Gd3Sb trigonal pyramid, corners with two equivalent O(3)Gd3Sb trigonal pyramids,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra,  an edgeedge with one O(1)Gd3Sb trigonal pyramid, and  an edgeedge with one O(3)Gd3Sb 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 corners with three equivalent O(4)Gd3Sb tetrahedra, corners with three equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3Sb trigonal pyramid, corners with two equivalent O(1)Gd3Sb trigonal pyramids,  an edgeedge with one O(4)Gd3Sb tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra,  an edgeedge with one O(1)Gd3Sb trigonal pyramid, and  an edgeedge with one O(3)Gd3Sb trigonal pyramid.
Gd3SbO7 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 hexagonal pyramids that share  a cornercorner with one Sb(1)O6 octahedra,  a cornercorner with one Sb(2)O6 octahedra,  a cornercorner with one Gd(3)O7 pentagonal bipyramid, edges with two equivalent Gd(1)O7 hexagonal pyramids,  an edgeedge with one Sb(1)O6 octahedra, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-49°. The Gd(1)-O(3) bond length is 2.49 Å. The Gd(1)-O(4) bond length is 2.36 Å. The Gd(1)-O(7) bond length is 2.31 Å. There is one shorter (2.36 Å) and one longer (2.50 Å) Gd(1)-O(2) bond length. There is one shorter (2.31 Å) and one longer (2.36 Å) Gd(1)-O(6) bond length. In the second Gd site, Gd(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(4), and two equivalent O(7) atoms. The Gd(2)-O(1) bond length is 2.56 Å. The Gd(2)-O(2) bond length is 2.71 Å. The Gd(2)-O(5) bond length is 2.91 Å. The Gd(2)-O(6) bond length is 2.29 Å. There is one shorter (2.46 Å) and one longer (2.62 Å) Gd(2)-O(4) bond length. There is one shorter (2.25 Å) and one longer (2.29 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 Gd(1)O7 hexagonal pyramid,  a cornercorner with one Sb(1)O6 octahedra,  a cornercorner with one Sb(2)O6 octahedra, edges with two equivalent Gd(1)O7 hexagonal pyramids,  an edgeedge with one Sb(1)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 44-45°. The Gd(3)-O(5) bond length is 2.45 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 (2.33 Å) and one longer (2.41 Å) Gd(3)-O(1) bond length. There is one shorter (2.33 Å) and one longer (2.42 Å) Gd(3)-O(3) bond length. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form SbO6 octahedra that share corners with two equivalent Gd(1)O7 hexagonal pyramids, corners with two equivalent Sb(2)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, edges with two equivalent Gd(1)O7 hexagonal pyramids, and edges with two equivalent Gd(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. Both Sb(1)-O(2) bond lengths are 1.98 Å. Both Sb(1)-O(3) bond lengths are 1.97 Å. Both Sb(1)-O(5) bond lengths are 2.02 Å. In the second Sb site, Sb(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form SbO6 octahedra that share corners with two equivalent Gd(1)O7 hexagonal pyramids, corners with two equivalent Sb(1)O6 octahedra, 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 39°. Both Sb(2)-O(1) bond lengths are 1.96 Å. Both Sb(2)-O(4) bond lengths are 2.03 Å. Both Sb(2)-O(5) bond lengths are 2.01 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 Sb(2) atom to form distorted OGd3Sb trigonal pyramids that share  a cornercorner with one O(6)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Sb tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra,  a cornercorner with one O(1)Gd3Sb trigonal pyramid, corners with four equivalent O(3)Gd3Sb trigonal pyramids,  an edgeedge with one O(4)Gd3Sb tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Sb 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 Sb(1) atom. In the third O site, O(3) is bonded to one Gd(1), two equivalent Gd(3), and one Sb(1) atom to form distorted OGd3Sb trigonal pyramids that share  a cornercorner with one O(4)Gd3Sb tetrahedra,  a cornercorner with one O(7)Gd4 tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3Sb trigonal pyramid, corners with four equivalent O(1)Gd3Sb trigonal pyramids,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(3)Gd3Sb trigonal pyramid. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one Sb(2) atom to form distorted OGd3Sb tetrahedra that share  a cornercorner with one O(4)Gd3Sb tetrahedra, corners with three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3Sb trigonal pyramid, corners with two equivalent O(1)Gd3Sb trigonal pyramids,  an edgeedge with one O(4)Gd3Sb tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(1)Gd3Sb trigonal pyramid. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), one Sb(1), and one Sb(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 three equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Sb tetrahedra,  a cornercorner with one O(1)Gd3Sb trigonal pyramid, corners with two equivalent O(3)Gd3Sb trigonal pyramids,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra,  an edgeedge with one O(1)Gd3Sb trigonal pyramid, and  an edgeedge with one O(3)Gd3Sb 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 corners with three equivalent O(4)Gd3Sb tetrahedra, corners with three equivalent O(6)Gd4 tetrahedra,  a cornercorner with one O(3)Gd3Sb trigonal pyramid, corners with two equivalent O(1)Gd3Sb trigonal pyramids,  an edgeedge with one O(4)Gd3Sb tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra,  an edgeedge with one O(1)Gd3Sb trigonal pyramid, and  an edgeedge with one O(3)Gd3Sb trigonal pyramid.