Ba2Ca3Ti4Tl2O12 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(4) atoms. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Ca site, Ca(2) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. In the second Ti site, Ti(2) is bonded to one O(4) and four equivalent O(1) atoms to form distorted corner-sharing TiO5 square pyramids. Tl(1) is bonded to five equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing TlO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded to two equivalent Ca(1), two equivalent Ca(2), and two equivalent Ti(1) atoms to form a mixture of distorted face, corner, and edge-sharing OCa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the third O site, O(3) is bonded to one Ba(1) and five equivalent Tl(1) atoms to form a mixture of distorted corner and edge-sharing OBaTl5 octahedra. The corner-sharing octahedral tilt angles are 1°. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one Ti(2) atom.
Ba2Ca3Ti4Tl2O12 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(4) atoms. The Ba(1)-O(3) bond length is 2.41 Å. All Ba(1)-O(4) bond lengths are 2.92 Å. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All Ca(1)-O(1) bond lengths are 2.40 Å. All Ca(1)-O(2) bond lengths are 2.67 Å. In the second Ca site, Ca(2) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. All Ca(2)-O(2) bond lengths are 2.55 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Ti(1)-O(2) bond lengths are 1.97 Å. In the second Ti site, Ti(2) is bonded to one O(4) and four equivalent O(1) atoms to form distorted corner-sharing TiO5 square pyramids. The Ti(2)-O(4) bond length is 1.78 Å. All Ti(2)-O(1) bond lengths are 2.01 Å. Tl(1) is bonded to five equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing TlO5 square pyramids. There is one shorter (2.31 Å) and four longer (2.78 Å) Tl(1)-O(3) bond lengths. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Ti(2) atoms. In the second O site, O(2) is bonded to two equivalent Ca(1), two equivalent Ca(2), and two equivalent Ti(1) atoms to form a mixture of distorted face, corner, and edge-sharing OCa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the third O site, O(3) is bonded to one Ba(1) and five equivalent Tl(1) atoms to form a mixture of distorted corner and edge-sharing OBaTl5 octahedra. The corner-sharing octahedral tilt angles are 1°. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one Ti(2) atom.