DOI: 10.17188/1685519
title: Materials Data on Cs2Bi4Se7 by Materials Project

description: Cs2Bi4Se7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.58–3.91 Å. In the second Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Cs–Se bond distances ranging from 3.61–3.84 Å. There are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–7°. There are a spread of Bi–Se bond distances ranging from 2.83–3.19 Å. In the second Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Bi–Se bond distances ranging from 2.89–3.08 Å. In the third Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–11°. There are a spread of Bi–Se bond distances ranging from 2.82–3.22 Å. In the fourth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 11°. There are a spread of Bi–Se bond distances ranging from 2.87–3.09 Å. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to three Cs1+ and three equivalent Bi3+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent Cs1+ and two equivalent Bi3+ atoms. In the third Se2- site, Se2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form SeCs2Bi3 square pyramids that share a cornercorner with one SeBi6 octahedra, corners with six SeCs2Bi3 trigonal bipyramids, edges with four SeCs3Bi3 octahedra, edges with two equivalent SeCs2Bi3 square pyramids, and edges with two SeCs2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth Se2- site, Se2- is bonded to three Cs1+ and three Bi3+ atoms to form distorted SeCs3Bi3 octahedra that share corners with two equivalent SeBi6 octahedra, corners with five SeCs2Bi3 trigonal bipyramids, edges with five SeBi6 octahedra, and edges with two equivalent SeCs2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 6°. In the fifth Se2- site, Se2- is bonded to two equivalent Cs1+ and three Bi3+ atoms to form distorted SeCs2Bi3 trigonal bipyramids that share corners with three SeBi6 octahedra, corners with four equivalent SeCs2Bi3 square pyramids, an edgeedge with one SeCs2Bi3 square pyramid, and edges with four SeCs2Bi3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 2–41°. In the sixth Se2- site, Se2- is bonded to one Cs1+ and four Bi3+ atoms to form SeCsBi4 trigonal bipyramids that share corners with three equivalent SeCs3Bi3 octahedra, corners with two equivalent SeCs2Bi3 square pyramids, corners with two equivalent SeCsBi4 trigonal bipyramids, edges with two equivalent SeBi6 octahedra, an edgeedge with one SeCs2Bi3 square pyramid, and edges with two equivalent SeCs2Bi3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 8–34°. In the seventh Se2- site, Se2- is bonded to six Bi3+ atoms to form SeBi6 octahedra that share corners with two equivalent SeCs3Bi3 octahedra, a cornercorner with one SeCs2Bi3 square pyramid, a cornercorner with one SeCs2Bi3 trigonal bipyramid, edges with seven SeCs3Bi3 octahedra, edges with two equivalent SeCs2Bi3 square pyramids, and edges with two equivalent SeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°.