BaTiCuAlO5 crystallizes in the tetragonal P4mm space group. Ba(1) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(3) atoms. Ti(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted corner-sharing TiO5 square pyramids. Cu(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. Al(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ti(1) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ba(1), two equivalent Cu(1), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one Ti(1) atom.
BaTiCuAlO5 crystallizes in the tetragonal P4mm space group. Ba(1) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(3) atoms. All Ba(1)-O(2) bond lengths are 2.99 Å. All Ba(1)-O(3) bond lengths are 2.79 Å. Ti(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted corner-sharing TiO5 square pyramids. The Ti(1)-O(3) bond length is 1.83 Å. All Ti(1)-O(1) bond lengths are 1.96 Å. Cu(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Cu(1)-O(2) bond lengths are 1.93 Å. Al(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All Al(1)-O(1) bond lengths are 2.43 Å. All Al(1)-O(2) bond lengths are 2.18 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ti(1) and two equivalent Al(1) atoms. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Ba(1), two equivalent Cu(1), and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one Ti(1) atom.