(CuCl)LaNb2O7 crystallizes in the orthorhombic Pmm2 space group. La(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form a mixture of face and corner-sharing LaO12 cuboctahedra. Nb(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms. Cu(1) is bonded in a distorted see-saw-like geometry to two equivalent O(4) and two equivalent Cl(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate 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 Nb(1) atoms to form distorted OLa2Nb2 trigonal pyramids that share corners with four equivalent O(3)La4Nb2 octahedra, corners with six equivalent O(2)La2Nb2 trigonal pyramids,  an edgeedge with one O(2)La2Nb2 trigonal pyramid, and faces with two equivalent O(3)La4Nb2 octahedra. The corner-sharing octahedral tilt angles are 59°. In the third O site, O(3) is bonded to four equivalent La(1) and two equivalent Nb(1) atoms to form OLa4Nb2 octahedra that share corners with four equivalent O(3)La4Nb2 octahedra, corners with eight equivalent O(2)La2Nb2 trigonal pyramids, edges with four equivalent O(3)La4Nb2 octahedra, and faces with four equivalent O(2)La2Nb2 trigonal pyramids. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded in a linear geometry to one Nb(1) and one Cu(1) atom. Cl(1) is bonded in a bent 120 degrees geometry to two equivalent Cu(1) atoms.
(CuCl)LaNb2O7 crystallizes in the orthorhombic Pmm2 space group. La(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form a mixture of face and corner-sharing LaO12 cuboctahedra. All La(1)-O(1) bond lengths are 2.68 Å. There are two shorter (2.67 Å) and two longer (2.68 Å) La(1)-O(2) bond lengths. There are two shorter (2.79 Å) and two longer (2.80 Å) La(1)-O(3) bond lengths. Nb(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms. The Nb(1)-O(3) bond length is 2.25 Å. The Nb(1)-O(4) bond length is 1.82 Å. There is one shorter (2.01 Å) and one longer (2.03 Å) Nb(1)-O(1) bond length. Both Nb(1)-O(2) bond lengths are 2.03 Å. Cu(1) is bonded in a distorted see-saw-like geometry to two equivalent O(4) and two equivalent Cl(1) atoms. Both Cu(1)-O(4) bond lengths are 1.86 Å. Both Cu(1)-Cl(1) bond lengths are 2.34 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate 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 Nb(1) atoms to form distorted OLa2Nb2 trigonal pyramids that share corners with four equivalent O(3)La4Nb2 octahedra, corners with six equivalent O(2)La2Nb2 trigonal pyramids,  an edgeedge with one O(2)La2Nb2 trigonal pyramid, and faces with two equivalent O(3)La4Nb2 octahedra. The corner-sharing octahedral tilt angles are 59°. In the third O site, O(3) is bonded to four equivalent La(1) and two equivalent Nb(1) atoms to form OLa4Nb2 octahedra that share corners with four equivalent O(3)La4Nb2 octahedra, corners with eight equivalent O(2)La2Nb2 trigonal pyramids, edges with four equivalent O(3)La4Nb2 octahedra, and faces with four equivalent O(2)La2Nb2 trigonal pyramids. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded in a linear geometry to one Nb(1) and one Cu(1) atom. Cl(1) is bonded in a bent 120 degrees geometry to two equivalent Cu(1) atoms.