Nd3TaO7 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(2), two equivalent O(3), and four equivalent O(4) atoms. In the second Nd site, Nd(2) is bonded to one O(1), one O(2), one O(3), and four equivalent O(4) atoms to form distorted NdO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O6 octahedra,  a cornercorner with one Nd(2)O7 pentagonal bipyramid, edges with two equivalent Ta(1)O6 octahedra, and edges with three equivalent Nd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. Ta(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(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 36°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Nd(2) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form a mixture of edge and corner-sharing ONd4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form a mixture of edge and corner-sharing ONd4 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Nd(1), two equivalent Nd(2), and one Ta(1) atom.
Nd3TaO7 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(2), two equivalent O(3), and four equivalent O(4) atoms. Both Nd(1)-O(2) bond lengths are 2.42 Å. Both Nd(1)-O(3) bond lengths are 2.38 Å. All Nd(1)-O(4) bond lengths are 2.72 Å. In the second Nd site, Nd(2) is bonded to one O(1), one O(2), one O(3), and four equivalent O(4) atoms to form distorted NdO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O6 octahedra,  a cornercorner with one Nd(2)O7 pentagonal bipyramid, edges with two equivalent Ta(1)O6 octahedra, and edges with three equivalent Nd(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. The Nd(2)-O(1) bond length is 2.60 Å. The Nd(2)-O(2) bond length is 2.29 Å. The Nd(2)-O(3) bond length is 2.33 Å. There are two shorter (2.40 Å) and two longer (2.48 Å) Nd(2)-O(4) bond lengths. Ta(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(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 36°. Both Ta(1)-O(1) bond lengths are 2.02 Å. All Ta(1)-O(4) bond lengths are 1.99 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Nd(2) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form a mixture of edge and corner-sharing ONd4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form a mixture of edge and corner-sharing ONd4 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Nd(1), two equivalent Nd(2), and one Ta(1) atom.