La3NbO7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded to one O(1), two equivalent O(2), and four equivalent O(3) atoms to form distorted LaO7 pentagonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with three equivalent La(1)O7 pentagonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with two equivalent La(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. In the second La site, La(2) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. Nb(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent La(1)O7 pentagonal bipyramids, and edges with four equivalent La(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 29°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent La(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded to two equivalent La(1) and two equivalent La(2) atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(2), two equivalent La(1), and one Nb(1) atom.
La3NbO7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded to one O(1), two equivalent O(2), and four equivalent O(3) atoms to form distorted LaO7 pentagonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with three equivalent La(1)O7 pentagonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with two equivalent La(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. The La(1)-O(1) bond length is 2.73 Å. There is one shorter (2.34 Å) and one longer (2.35 Å) La(1)-O(2) bond length. There are two shorter (2.49 Å) and two longer (2.51 Å) La(1)-O(3) bond lengths. In the second La site, La(2) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. All La(2)-O(2) bond lengths are 2.44 Å. All La(2)-O(3) bond lengths are 2.77 Å. Nb(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent La(1)O7 pentagonal bipyramids, and edges with four equivalent La(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 29°. Both Nb(1)-O(1) bond lengths are 2.02 Å. All Nb(1)-O(3) bond lengths are 2.01 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent La(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded to two equivalent La(1) and two equivalent La(2) atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(2), two equivalent La(1), and one Nb(1) atom.