Nd3SbO7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. In the second Nd site, Nd(2) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted NdO7 pentagonal bipyramids that share corners with two equivalent Sb(1)O6 octahedra,  a cornercorner with one Nd(2)O7 pentagonal bipyramid, edges with two equivalent Sb(1)O6 octahedra, and edges with three equivalent Nd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Nd(2)O7 pentagonal bipyramids, and edges with four equivalent Nd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Nd(1), two equivalent Nd(2), and one Sb(1) atom. In the second O site, O(2) is bonded to two equivalent Nd(2) and two equivalent Sb(1) atoms to form distorted ONd2Sb2 trigonal pyramids that share corners with two equivalent O(3)Nd4 tetrahedra, corners with two equivalent O(2)Nd2Sb2 trigonal pyramids, and  an edgeedge with one O(4)Nd4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(3)Nd4 tetrahedra, corners with four equivalent O(4)Nd4 tetrahedra, corners with two equivalent O(2)Nd2Sb2 trigonal pyramids, and  an edgeedge with one O(4)Nd4 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(4)Nd4 tetrahedra, corners with four equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and  an edgeedge with one O(2)Nd2Sb2 trigonal pyramid.
Nd3SbO7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Both Nd(1)-O(3) bond lengths are 2.39 Å. Both Nd(1)-O(4) bond lengths are 2.42 Å. All Nd(1)-O(1) bond lengths are 2.72 Å. In the second Nd site, Nd(2) is bonded to one O(2), one O(3), one O(4), and four equivalent O(1) atoms to form distorted NdO7 pentagonal bipyramids that share corners with two equivalent Sb(1)O6 octahedra,  a cornercorner with one Nd(2)O7 pentagonal bipyramid, edges with two equivalent Sb(1)O6 octahedra, and edges with three equivalent Nd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. The Nd(2)-O(2) bond length is 2.59 Å. The Nd(2)-O(3) bond length is 2.33 Å. The Nd(2)-O(4) bond length is 2.30 Å. There are two shorter (2.40 Å) and two longer (2.48 Å) Nd(2)-O(1) bond lengths. Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Nd(2)O7 pentagonal bipyramids, and edges with four equivalent Nd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. Both Sb(1)-O(2) bond lengths are 2.04 Å. All Sb(1)-O(1) bond lengths are 1.98 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Nd(1), two equivalent Nd(2), and one Sb(1) atom. In the second O site, O(2) is bonded to two equivalent Nd(2) and two equivalent Sb(1) atoms to form distorted ONd2Sb2 trigonal pyramids that share corners with two equivalent O(3)Nd4 tetrahedra, corners with two equivalent O(2)Nd2Sb2 trigonal pyramids, and  an edgeedge with one O(4)Nd4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(3)Nd4 tetrahedra, corners with four equivalent O(4)Nd4 tetrahedra, corners with two equivalent O(2)Nd2Sb2 trigonal pyramids, and  an edgeedge with one O(4)Nd4 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(4)Nd4 tetrahedra, corners with four equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and  an edgeedge with one O(2)Nd2Sb2 trigonal pyramid.