KCr5Se8 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 10-coordinate geometry to two equivalent Se(1), four equivalent Se(2), and four equivalent Se(3) atoms. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of edge and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Cr site, Cr(2) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(4) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. In the third Cr site, Cr(3) is bonded to one Se(1), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one Cr(2), one Cr(3), and two equivalent Cr(1) atoms. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent K(1), one Cr(1), and two equivalent Cr(2) atoms. In the third Se site, Se(3) is bonded in a 3-coordinate geometry to two equivalent K(1) and three equivalent Cr(3) atoms. In the fourth Se site, Se(4) is bonded to two equivalent Cr(3) and three equivalent Cr(2) atoms to form distorted edge-sharing SeCr5 trigonal bipyramids.
KCr5Se8 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 10-coordinate geometry to two equivalent Se(1), four equivalent Se(2), and four equivalent Se(3) atoms. Both K(1)-Se(1) bond lengths are 3.77 Å. All K(1)-Se(2) bond lengths are 3.54 Å. All K(1)-Se(3) bond lengths are 3.76 Å. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of edge and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. Both Cr(1)-Se(2) bond lengths are 2.53 Å. All Cr(1)-Se(1) bond lengths are 2.53 Å. In the second Cr site, Cr(2) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(4) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. The Cr(2)-Se(1) bond length is 2.53 Å. Both Cr(2)-Se(2) bond lengths are 2.50 Å. There is one shorter (2.56 Å) and two longer (2.65 Å) Cr(2)-Se(4) bond lengths. In the third Cr site, Cr(3) is bonded to one Se(1), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of edge, face, and corner-sharing CrSe6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. The Cr(3)-Se(1) bond length is 2.57 Å. Both Cr(3)-Se(4) bond lengths are 2.65 Å. There is one shorter (2.49 Å) and two longer (2.50 Å) Cr(3)-Se(3) bond lengths. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one Cr(2), one Cr(3), and two equivalent Cr(1) atoms. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent K(1), one Cr(1), and two equivalent Cr(2) atoms. In the third Se site, Se(3) is bonded in a 3-coordinate geometry to two equivalent K(1) and three equivalent Cr(3) atoms. In the fourth Se site, Se(4) is bonded to two equivalent Cr(3) and three equivalent Cr(2) atoms to form distorted edge-sharing SeCr5 trigonal bipyramids.