KTl4(CoSe)10 crystallizes in the tetragonal I4/mmm space group. K(1) is bonded in a body-centered cubic geometry to eight equivalent Se(1) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Se(1) and two equivalent Se(5) atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. In the second Co site, Co(2) is bonded to four equivalent Se(2,4) atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. In the third Co site, Co(3) is bonded to four equivalent Se(3) atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted body-centered cubic geometry to four equivalent Se(2,4) and four equivalent Se(5) atoms. In the second Tl site, Tl(2) is bonded in a distorted body-centered cubic geometry to four equivalent Se(2,4) and four equivalent Se(3) atoms. There are four inequivalent Se sites. In the first Se site, Se(3) is bonded in a 4-coordinate geometry to four equivalent Co(3) and four equivalent Tl(2) atoms. In the second Se site, Se(5) is bonded in a 4-coordinate geometry to four equivalent Co(1) and four equivalent Tl(1) atoms. In the third Se site, Se(1) is bonded in a 8-coordinate geometry to four equivalent K(1) and four equivalent Co(1) atoms. In the fourth Se site, Se(2,4) is bonded in a 4-coordinate geometry to four equivalent Co(2) and four equivalent Tl(1) atoms.
KTl4(CoSe)10 crystallizes in the tetragonal I4/mmm space group. K(1) is bonded in a body-centered cubic geometry to eight equivalent Se(1) atoms. All K(1)-Se(1) bond lengths are 3.40 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent Se(1) and two equivalent Se(5) atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. Both Co(1)-Se(1) bond lengths are 2.34 Å. Both Co(1)-Se(5) bond lengths are 2.34 Å. In the second Co site, Co(2) is bonded to four equivalent Se(2,4) atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. All Co(2)-Se(2,4) bond lengths are 2.33 Å. In the third Co site, Co(3) is bonded to four equivalent Se(3) atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. All Co(3)-Se(3) bond lengths are 2.33 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a distorted body-centered cubic geometry to four equivalent Se(2,4) and four equivalent Se(5) atoms. All Tl(1)-Se(2,4) bond lengths are 3.41 Å. All Tl(1)-Se(5) bond lengths are 3.40 Å. In the second Tl site, Tl(2) is bonded in a distorted body-centered cubic geometry to four equivalent Se(2,4) and four equivalent Se(3) atoms. All Tl(2)-Se(2,4) bond lengths are 3.41 Å. All Tl(2)-Se(3) bond lengths are 3.41 Å. There are four inequivalent Se sites. In the first Se site, Se(3) is bonded in a 4-coordinate geometry to four equivalent Co(3) and four equivalent Tl(2) atoms. In the second Se site, Se(5) is bonded in a 4-coordinate geometry to four equivalent Co(1) and four equivalent Tl(1) atoms. In the third Se site, Se(1) is bonded in a 8-coordinate geometry to four equivalent K(1) and four equivalent Co(1) atoms. In the fourth Se site, Se(2,4) is bonded in a 4-coordinate geometry to four equivalent Co(2) and four equivalent Tl(1) atoms.