Bi2LaTaO7 crystallizes in the orthorhombic Imma space group. La(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. Ta(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra and corners with four equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-56°. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to two equivalent O(4) and four equivalent O(3) atoms to form BiO6 octahedra that share corners with two equivalent Bi(1)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-68°. In the second Bi site, Bi(2) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to two equivalent La(1) and two equivalent Bi(2) atoms to form OLa2Bi2 tetrahedra that share corners with two equivalent O(4)Bi4 tetrahedra, corners with four equivalent O(2)La2Bi2 tetrahedra, and  an edgeedge with one O(4)Bi4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(1), one Ta(1), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form OBi4 tetrahedra that share corners with two equivalent O(2)La2Bi2 tetrahedra, corners with four equivalent O(4)Bi4 tetrahedra, and  an edgeedge with one O(2)La2Bi2 tetrahedra.
Bi2LaTaO7 crystallizes in the orthorhombic Imma space group. La(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(3) atoms. Both La(1)-O(2) bond lengths are 2.36 Å. All La(1)-O(3) bond lengths are 2.50 Å. Ta(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra and corners with four equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-56°. Both Ta(1)-O(1) bond lengths are 1.97 Å. All Ta(1)-O(3) bond lengths are 2.02 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to two equivalent O(4) and four equivalent O(3) atoms to form BiO6 octahedra that share corners with two equivalent Bi(1)O6 octahedra and corners with four equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-68°. Both Bi(1)-O(4) bond lengths are 2.35 Å. All Bi(1)-O(3) bond lengths are 2.41 Å. In the second Bi site, Bi(2) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms. Both Bi(2)-O(2) bond lengths are 2.44 Å. Both Bi(2)-O(4) bond lengths are 2.45 Å. All Bi(2)-O(3) bond lengths are 2.78 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to two equivalent La(1) and two equivalent Bi(2) atoms to form OLa2Bi2 tetrahedra that share corners with two equivalent O(4)Bi4 tetrahedra, corners with four equivalent O(2)La2Bi2 tetrahedra, and  an edgeedge with one O(4)Bi4 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(1), one Ta(1), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form OBi4 tetrahedra that share corners with two equivalent O(2)La2Bi2 tetrahedra, corners with four equivalent O(4)Bi4 tetrahedra, and  an edgeedge with one O(2)La2Bi2 tetrahedra.