TlSr2CaCu2O7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. Ca(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Cu(1) is bonded to one O(2) and four equivalent O(1) atoms to form CuO5 square pyramids that share  a cornercorner with one Tl(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. Tl(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and edges with four equivalent Tl(1)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Ca(1), and two equivalent Cu(1) atoms to form distorted OSr2Ca2Cu2 octahedra that share corners with two equivalent O(3)Sr2Tl4 octahedra, corners with four equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with three equivalent O(1)Sr2Ca2Cu2 octahedra, faces with two equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Cu(1), and one Tl(1) atom to form distorted OSr4TlCu octahedra that share corners with five equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, edges with four equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the third O site, O(3) is bonded to two equivalent Sr(1) and four equivalent Tl(1) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with eight equivalent O(2)Sr4TlCu octahedra. The corner-sharing octahedral tilt angles range from 0-43°.
TlSr2CaCu2O7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. The Sr(1)-O(3) bond length is 2.57 Å. All Sr(1)-O(1) bond lengths are 2.75 Å. All Sr(1)-O(2) bond lengths are 2.71 Å. Ca(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Ca(1)-O(1) bond lengths are 2.46 Å. Cu(1) is bonded to one O(2) and four equivalent O(1) atoms to form CuO5 square pyramids that share  a cornercorner with one Tl(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. The Cu(1)-O(2) bond length is 2.27 Å. All Cu(1)-O(1) bond lengths are 1.90 Å. Tl(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form TlO6 octahedra that share corners with four equivalent Tl(1)O6 octahedra, corners with two equivalent Cu(1)O5 square pyramids, and edges with four equivalent Tl(1)O6 octahedra. The corner-sharing octahedra are not tilted. Both Tl(1)-O(2) bond lengths are 2.12 Å. All Tl(1)-O(3) bond lengths are 2.67 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Ca(1), and two equivalent Cu(1) atoms to form distorted OSr2Ca2Cu2 octahedra that share corners with two equivalent O(3)Sr2Tl4 octahedra, corners with four equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with three equivalent O(1)Sr2Ca2Cu2 octahedra, faces with two equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Cu(1), and one Tl(1) atom to form distorted OSr4TlCu octahedra that share corners with five equivalent O(2)Sr4TlCu octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, edges with four equivalent O(2)Sr4TlCu octahedra, and faces with four equivalent O(1)Sr2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the third O site, O(3) is bonded to two equivalent Sr(1) and four equivalent Tl(1) atoms to form OSr2Tl4 octahedra that share corners with four equivalent O(3)Sr2Tl4 octahedra, corners with eight equivalent O(1)Sr2Ca2Cu2 octahedra, edges with four equivalent O(3)Sr2Tl4 octahedra, and edges with eight equivalent O(2)Sr4TlCu octahedra. The corner-sharing octahedral tilt angles range from 0-43°.