Gd3MoO7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 7-coordinate geometry to one O(2), one O(4), one O(5), two equivalent O(6), and two equivalent O(7) atoms. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. In the third Gd site, Gd(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form distorted GdO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-45°. Mo(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form MoO6 octahedra that share corners with two equivalent Mo(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 30°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Gd(1), one Gd(2), one Gd(3), and one Mo(1) atom. In the second O site, O(6) is bonded to two equivalent Gd(1) and two equivalent Gd(3) atoms to form OGd4 tetrahedra that share corners with two equivalent O(2)Gd3Mo tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Mo trigonal pyramids,  an edgeedge with one O(2)Gd3Mo tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Mo trigonal pyramid. In the third O site, O(7) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(2)Gd3Mo tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra, corners with four equivalent O(7)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Mo trigonal pyramids,  an edgeedge with one O(2)Gd3Mo tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Mo trigonal pyramid. In the fourth O site, O(1) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), and two equivalent Mo(1) atoms. In the fifth O site, O(2) is bonded to one Gd(1), one Gd(2), one Gd(3), and one Mo(1) atom to form OGd3Mo tetrahedra that share corners with two equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and edges with two equivalent O(4)Gd3Mo trigonal pyramids. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Gd(2), one Gd(3), and one Mo(1) atom. In the seventh O site, O(4) is bonded to one Gd(1), one Gd(2), one Gd(3), and one Mo(1) atom to form distorted OGd3Mo trigonal pyramids that share corners with two equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and edges with two equivalent O(2)Gd3Mo tetrahedra.
Gd3MoO7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 7-coordinate geometry to one O(2), one O(4), one O(5), two equivalent O(6), and two equivalent O(7) atoms. The Gd(1)-O(2) bond length is 2.31 Å. The Gd(1)-O(4) bond length is 2.45 Å. The Gd(1)-O(5) bond length is 2.78 Å. There is one shorter (2.36 Å) and one longer (2.40 Å) Gd(1)-O(6) bond length. There is one shorter (2.34 Å) and one longer (2.36 Å) Gd(1)-O(7) 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(3), one O(4), one O(5), and two equivalent O(7) atoms. The Gd(2)-O(1) bond length is 2.69 Å. The Gd(2)-O(2) bond length is 2.35 Å. The Gd(2)-O(3) bond length is 2.35 Å. The Gd(2)-O(4) bond length is 2.36 Å. The Gd(2)-O(5) bond length is 2.41 Å. There is one shorter (2.27 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(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form distorted GdO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Gd(3)O7 pentagonal bipyramids, and edges with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-45°. The Gd(3)-O(1) bond length is 2.58 Å. The Gd(3)-O(2) bond length is 2.34 Å. The Gd(3)-O(3) bond length is 2.41 Å. The Gd(3)-O(4) bond length is 2.41 Å. The Gd(3)-O(5) bond length is 2.40 Å. There is one shorter (2.23 Å) and one longer (2.26 Å) Gd(3)-O(6) bond length. Mo(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form MoO6 octahedra that share corners with two equivalent Mo(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 30°. The Mo(1)-O(2) bond length is 2.08 Å. The Mo(1)-O(3) bond length is 1.88 Å. The Mo(1)-O(4) bond length is 1.99 Å. The Mo(1)-O(5) bond length is 1.93 Å. There is one shorter (1.93 Å) and one longer (1.94 Å) Mo(1)-O(1) bond length. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Gd(1), one Gd(2), one Gd(3), and one Mo(1) atom. In the second O site, O(6) is bonded to two equivalent Gd(1) and two equivalent Gd(3) atoms to form OGd4 tetrahedra that share corners with two equivalent O(2)Gd3Mo tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra, corners with four equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Mo trigonal pyramids,  an edgeedge with one O(2)Gd3Mo tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Mo trigonal pyramid. In the third O site, O(7) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(2)Gd3Mo tetrahedra, corners with two equivalent O(6)Gd4 tetrahedra, corners with four equivalent O(7)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Mo trigonal pyramids,  an edgeedge with one O(2)Gd3Mo tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Mo trigonal pyramid. In the fourth O site, O(1) is bonded in a 4-coordinate geometry to one Gd(2), one Gd(3), and two equivalent Mo(1) atoms. In the fifth O site, O(2) is bonded to one Gd(1), one Gd(2), one Gd(3), and one Mo(1) atom to form OGd3Mo tetrahedra that share corners with two equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and edges with two equivalent O(4)Gd3Mo trigonal pyramids. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Gd(2), one Gd(3), and one Mo(1) atom. In the seventh O site, O(4) is bonded to one Gd(1), one Gd(2), one Gd(3), and one Mo(1) atom to form distorted OGd3Mo trigonal pyramids that share corners with two equivalent O(6)Gd4 tetrahedra, corners with two equivalent O(7)Gd4 tetrahedra,  an edgeedge with one O(6)Gd4 tetrahedra,  an edgeedge with one O(7)Gd4 tetrahedra, and edges with two equivalent O(2)Gd3Mo tetrahedra.