KTl(CoSe)4 crystallizes in the tetragonal P4/mmm space group. K(1) is bonded in a body-centered cubic geometry to eight equivalent Se(2) atoms. Co(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form a mixture of corner and edge-sharing CoSe4 tetrahedra. Tl(1) is bonded in a distorted 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 Co(1) and four equivalent Tl(1) atoms. In the second Se site, Se(2) is bonded in a 8-coordinate geometry to four equivalent K(1) and four equivalent Co(1) atoms.
KTl(CoSe)4 crystallizes in the tetragonal P4/mmm space group. K(1) is bonded in a body-centered cubic geometry to eight equivalent Se(2) atoms. All K(1)-Se(2) bond lengths are 3.41 Å. Co(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form a mixture of corner and edge-sharing CoSe4 tetrahedra. Both Co(1)-Se(1) bond lengths are 2.34 Å. Both Co(1)-Se(2) bond lengths are 2.35 Å. Tl(1) is bonded in a distorted body-centered cubic geometry to eight equivalent Se(1) atoms. All Tl(1)-Se(1) bond lengths are 3.42 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to four equivalent Co(1) and four equivalent Tl(1) atoms. In the second Se site, Se(2) is bonded in a 8-coordinate geometry to four equivalent K(1) and four equivalent Co(1) atoms.