DOI: 10.17188/1270140
title: Materials Data on KCu(BiS2)2 by Materials Project

description: KBi2CuS4 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. K1+ is bonded to seven S2- atoms to form distorted KS7 pentagonal bipyramids that share corners with eight BiS6 octahedra, corners with two equivalent CuS4 trigonal pyramids, edges with six BiS6 octahedra, edges with three equivalent CuS4 trigonal pyramids, and faces with two equivalent KS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 18–74°. There are a spread of K–S bond distances ranging from 3.26–3.43 Å. Cu1+ is bonded to four S2- atoms to form CuS4 trigonal pyramids that share corners with two BiS6 octahedra, corners with two equivalent KS7 pentagonal bipyramids, corners with two equivalent CuS4 trigonal pyramids, edges with four BiS6 octahedra, and edges with three equivalent KS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 3–15°. There are a spread of Cu–S bond distances ranging from 2.30–2.71 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with three equivalent BiS6 octahedra, corners with four equivalent KS7 pentagonal bipyramids, a cornercorner with one CuS4 trigonal pyramid, edges with five BiS6 octahedra, edges with three equivalent KS7 pentagonal bipyramids, and edges with two equivalent CuS4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 6–35°. There are a spread of Bi–S bond distances ranging from 2.71–3.13 Å. In the second Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with three equivalent BiS6 octahedra, corners with four equivalent KS7 pentagonal bipyramids, a cornercorner with one CuS4 trigonal pyramid, edges with five BiS6 octahedra, edges with three equivalent KS7 pentagonal bipyramids, and edges with two equivalent CuS4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 6–35°. There are a spread of Bi–S bond distances ranging from 2.69–3.08 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to one K1+ and four Bi3+ atoms to form SKBi4 square pyramids that share corners with eight SK2CuBi3 octahedra, edges with four SK2CuBi3 octahedra, and edges with two equivalent SKBi4 square pyramids. The corner-sharing octahedra tilt angles range from 0–82°. In the second S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent K1+, two equivalent Cu1+, and two Bi3+ atoms. In the third S2- site, S2- is bonded to two equivalent K1+, one Cu1+, and three Bi3+ atoms to form distorted SK2CuBi3 octahedra that share corners with two equivalent SK2CuBi3 octahedra, corners with six equivalent SKBi4 square pyramids, edges with four SK2CuBi3 octahedra, an edgeedge with one SKBi4 square pyramid, and a faceface with one SK2CuBi3 octahedra. The corner-sharing octahedral tilt angles are 65°. In the fourth S2- site, S2- is bonded to two equivalent K1+, one Cu1+, and three Bi3+ atoms to form distorted SK2CuBi3 octahedra that share corners with two equivalent SK2CuBi3 octahedra, corners with two equivalent SKBi4 square pyramids, edges with four SK2CuBi3 octahedra, edges with three equivalent SKBi4 square pyramids, and a faceface with one SK2CuBi3 octahedra. The corner-sharing octahedral tilt angles are 65°.