La2O3MgO is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form corner-sharing MgO6 octahedra. The corner-sharing octahedra are not tilted. La(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Mg(1) and five equivalent La(1) atoms to form distorted OLa5Mg octahedra that share corners with five equivalent O(2)La5Mg octahedra, corners with twelve equivalent O(1)La4Mg2 octahedra, edges with eight equivalent O(2)La5Mg octahedra, and faces with four equivalent O(1)La4Mg2 octahedra. The corner-sharing octahedral tilt angles range from 0-50°. In the second O site, O(1) is bonded to two equivalent Mg(1) and four equivalent La(1) atoms to form distorted OLa4Mg2 octahedra that share corners with two equivalent O(1)La4Mg2 octahedra, corners with twelve equivalent O(2)La5Mg octahedra, edges with two equivalent O(1)La4Mg2 octahedra, faces with four equivalent O(1)La4Mg2 octahedra, and faces with four equivalent O(2)La5Mg octahedra. The corner-sharing octahedral tilt angles range from 0-50°.
La2O3MgO is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form corner-sharing MgO6 octahedra. The corner-sharing octahedra are not tilted. Both Mg(1)-O(2) bond lengths are 2.24 Å. All Mg(1)-O(1) bond lengths are 1.97 Å. La(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. All La(1)-O(1) bond lengths are 2.61 Å. There is one shorter (2.31 Å) and four longer (2.83 Å) La(1)-O(2) bond lengths. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Mg(1) and five equivalent La(1) atoms to form distorted OLa5Mg octahedra that share corners with five equivalent O(2)La5Mg octahedra, corners with twelve equivalent O(1)La4Mg2 octahedra, edges with eight equivalent O(2)La5Mg octahedra, and faces with four equivalent O(1)La4Mg2 octahedra. The corner-sharing octahedral tilt angles range from 0-50°. In the second O site, O(1) is bonded to two equivalent Mg(1) and four equivalent La(1) atoms to form distorted OLa4Mg2 octahedra that share corners with two equivalent O(1)La4Mg2 octahedra, corners with twelve equivalent O(2)La5Mg octahedra, edges with two equivalent O(1)La4Mg2 octahedra, faces with four equivalent O(1)La4Mg2 octahedra, and faces with four equivalent O(2)La5Mg octahedra. The corner-sharing octahedral tilt angles range from 0-50°.