TlCu4Se3 crystallizes in the tetragonal P4/mmm space group. Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form a mixture of distorted corner and edge-sharing CuSe4 tetrahedra. Tl(1) is bonded in a body-centered cubic geometry to eight equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to four equivalent Cu(1) and four equivalent Tl(1) atoms. In the second Se site, Se(2) is bonded in a body-centered cubic geometry to eight equivalent Cu(1) atoms.
TlCu4Se3 crystallizes in the tetragonal P4/mmm space group. Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form a mixture of distorted corner and edge-sharing CuSe4 tetrahedra. Both Cu(1)-Se(1) bond lengths are 2.43 Å. Both Cu(1)-Se(2) bond lengths are 2.53 Å. Tl(1) is bonded in a body-centered cubic geometry to eight equivalent Se(1) atoms. All Tl(1)-Se(1) bond lengths are 3.36 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to four equivalent Cu(1) and four equivalent Tl(1) atoms. In the second Se site, Se(2) is bonded in a body-centered cubic geometry to eight equivalent Cu(1) atoms.