Ba2Ti2TlAlO7 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(1) atoms. Ti(1) is bonded in a 5-coordinate geometry to one O(1) and four equivalent O(2) atoms. Tl(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. Al(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one Ti(1) atom. In the second O site, O(2) is bonded to two equivalent Ti(1) and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OTi2Al2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ba(1) and four equivalent Tl(1) atoms to form a mixture of edge and corner-sharing OBa2Tl4 octahedra. The corner-sharing octahedra are not tilted.
Ba2Ti2TlAlO7 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(1) atoms. The Ba(1)-O(3) bond length is 2.54 Å. There are three shorter (2.89 Å) and one longer (2.90 Å) Ba(1)-O(1) bond length. Ti(1) is bonded in a 5-coordinate geometry to one O(1) and four equivalent O(2) atoms. The Ti(1)-O(1) bond length is 1.80 Å. There are two shorter (1.99 Å) and two longer (2.00 Å) Ti(1)-O(2) bond lengths. Tl(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. All Tl(1)-O(3) bond lengths are 2.63 Å. Al(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. There are four shorter (2.20 Å) and four longer (2.27 Å) Al(1)-O(2) bond lengths. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one Ti(1) atom. In the second O site, O(2) is bonded to two equivalent Ti(1) and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OTi2Al2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ba(1) and four equivalent Tl(1) atoms to form a mixture of edge and corner-sharing OBa2Tl4 octahedra. The corner-sharing octahedra are not tilted.