Gd3NbO7 crystallizes in the monoclinic Pc space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(2), one O(4), one O(5), one O(7), and two equivalent O(1) atoms to form distorted GdO6 octahedra that share corners with two equivalent Gd(1)O6 octahedra and corners with two equivalent Nb(1)O5 tetrahedra. The corner-sharing octahedral tilt angles are 64°. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(6), two equivalent O(2), and two equivalent O(4) atoms. In the third Gd site, Gd(3) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(4), one O(6), two equivalent O(5), and two equivalent O(7) atoms. Nb(1) is bonded to one O(2), one O(3), one O(7), and two equivalent O(6) atoms to form distorted NbO5 tetrahedra that share corners with two equivalent Gd(1)O6 octahedra and corners with two equivalent Nb(1)O5 tetrahedra. The corner-sharing octahedral tilt angles range from 60-63°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Gd(2), one Gd(3), and two equivalent Gd(1) atoms to form corner-sharing OGd4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Gd(1), two equivalent Gd(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Gd(2), one Gd(3), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Gd(1), one Gd(3), and two equivalent Gd(2) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Gd(1) and two equivalent Gd(3) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), and two equivalent Nb(1) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Gd(1), two equivalent Gd(3), and one Nb(1) atom.
Gd3NbO7 crystallizes in the monoclinic Pc space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(2), one O(4), one O(5), one O(7), and two equivalent O(1) atoms to form distorted GdO6 octahedra that share corners with two equivalent Gd(1)O6 octahedra and corners with two equivalent Nb(1)O5 tetrahedra. The corner-sharing octahedral tilt angles are 64°. The Gd(1)-O(2) bond length is 2.44 Å. The Gd(1)-O(4) bond length is 2.24 Å. The Gd(1)-O(5) bond length is 2.22 Å. The Gd(1)-O(7) bond length is 2.52 Å. Both Gd(1)-O(1) bond lengths are 2.26 Å. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(6), two equivalent O(2), and two equivalent O(4) atoms. The Gd(2)-O(1) bond length is 2.31 Å. The Gd(2)-O(3) bond length is 2.61 Å. The Gd(2)-O(6) bond length is 2.32 Å. There is one shorter (2.58 Å) and one longer (2.66 Å) Gd(2)-O(2) bond length. There is one shorter (2.17 Å) and one longer (2.41 Å) Gd(2)-O(4) bond length. In the third Gd site, Gd(3) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(4), one O(6), two equivalent O(5), and two equivalent O(7) atoms. The Gd(3)-O(1) bond length is 2.31 Å. The Gd(3)-O(3) bond length is 2.30 Å. The Gd(3)-O(4) bond length is 3.19 Å. The Gd(3)-O(6) bond length is 2.82 Å. There is one shorter (2.18 Å) and one longer (2.32 Å) Gd(3)-O(5) bond length. There is one shorter (2.52 Å) and one longer (2.67 Å) Gd(3)-O(7) bond length. Nb(1) is bonded to one O(2), one O(3), one O(7), and two equivalent O(6) atoms to form distorted NbO5 tetrahedra that share corners with two equivalent Gd(1)O6 octahedra and corners with two equivalent Nb(1)O5 tetrahedra. The corner-sharing octahedral tilt angles range from 60-63°. The Nb(1)-O(2) bond length is 1.93 Å. The Nb(1)-O(3) bond length is 1.91 Å. The Nb(1)-O(7) bond length is 1.92 Å. There is one shorter (1.91 Å) and one longer (2.56 Å) Nb(1)-O(6) bond length. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Gd(2), one Gd(3), and two equivalent Gd(1) atoms to form corner-sharing OGd4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Gd(1), two equivalent Gd(2), and one Nb(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Gd(2), one Gd(3), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Gd(1), one Gd(3), and two equivalent Gd(2) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Gd(1) and two equivalent Gd(3) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), and two equivalent Nb(1) atoms. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Gd(1), two equivalent Gd(3), and one Nb(1) atom.