Materials Data on K5CuSb2 by Materials Project
K5CuSb2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 12-coordinate geometry to eight K1+ and six equivalent Sb3- atoms. There are six shorter (3.74 Å) and two longer (3.84 Å) K–K bond lengths. All K–Sb bond lengths are 4.11 Å. In the second K1+ site, K1+ is bonded in a distorted trigonal non-coplanar geometry to one K1+ and three equivalent Sb3- atoms. All K–Sb bond lengths are 3.82 Å. In the third K1+ site, K1+ is bonded to three equivalent K1+ and four equivalent Sb3- atoms to form a mixture of distorted corner, edge, and face-sharing KK3Sb4 tetrahedra. There are three shorter (3.55 Å) and one longer (3.64 Å) K–Sb bond lengths. Cu1+ is bonded in a linear geometry to two equivalent Sb3- atoms. Both Cu–Sb bond lengths are 2.51 Å. Sb3- is bonded in a 8-coordinate geometry to ten K1+ and one Cu1+ atom.