Materials Data on Cs(Bi2Te3)2 by Materials Project
CsBi4Te6 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten Te2- atoms. There are a spread of Cs–Te bond distances ranging from 3.88–4.29 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine Te2- atoms. There are a spread of Cs–Te bond distances ranging from 3.80–4.21 Å. There are eight inequivalent Bi+2.75+ sites. In the first Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, a cornercorner with one BiTe5 square pyramid, and edges with seven BiTe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Bi–Te bond distances ranging from 3.03–3.45 Å. In the second Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing BiTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Bi–Te bond distances ranging from 3.14–3.27 Å. In the third Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, a cornercorner with one BiTe5 square pyramid, and edges with eleven BiTe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Bi–Te bond distances ranging from 3.09–3.32 Å. In the fourth Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, edges with seven BiTe6 octahedra, and edges with four BiTe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Bi–Te bond distances ranging from 3.04–3.44 Å. In the fifth Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing BiTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–15°. There are a spread of Bi–Te bond distances ranging from 3.04–3.45 Å. In the sixth Bi+2.75+ site, Bi+2.75+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three BiTe6 octahedra, edges with five BiTe6 octahedra, and edges with two equivalent BiTe5 square pyramids. The corner-sharing octahedra tilt angles range from 7–15°. There are a spread of Bi–Te bond distances ranging from 3.00–3.40 Å. In the seventh Bi+2.75+ site, Bi+2.75+ is bonded to five Te2- atoms to form BiTe5 square pyramids that share a cornercorner with one BiTe6 octahedra, corners with two equivalent BiTe5 square pyramids, edges with two equivalent BiTe6 octahedra, and edges with three BiTe5 square pyramids. The corner-sharing octahedral tilt angles are 10°. There are a spread of Bi–Te bond distances ranging from 3.06–3.45 Å. In the eighth Bi+2.75+ site, Bi+2.75+ is bonded to five Te2- atoms to form BiTe5 square pyramids that share a cornercorner with one BiTe6 octahedra, corners with two equivalent BiTe5 square pyramids, edges with four BiTe6 octahedra, and edges with three BiTe5 square pyramids. The corner-sharing octahedral tilt angles are 6°. There are a spread of Bi–Te bond distances ranging from 3.09–3.55 Å. There are twelve inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six Bi+2.75+ atoms to form TeBi6 octahedra that share a cornercorner with one TeBi6 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, edges with eight TeBi6 octahedra, and edges with three TeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 7°. In the second Te2- site, Te2- is bonded to one Cs1+ and four Bi+2.75+ atoms to form distorted TeCsBi4 trigonal bipyramids that share corners with three TeCs2Bi4 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, and edges with three TeBi6 octahedra. The corner-sharing octahedra tilt angles range from 7–13°. In the third Te2- site, Te2- is bonded in a 7-coordinate geometry to three Cs1+, two equivalent Bi+2.75+, and two equivalent Te2- atoms. Both Te–Te bond lengths are 3.58 Å. In the fourth Te2- site, Te2- is bonded to two equivalent Cs1+ and four Bi+2.75+ atoms to form TeCs2Bi4 octahedra that share corners with two equivalent TeBi6 octahedra, corners with four TeCsBi4 trigonal bipyramids, and edges with seven TeBi6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the fifth Te2- site, Te2- is bonded to six Bi+2.75+ atoms to form TeBi6 octahedra that share corners with four TeBi6 octahedra, edges with nine TeBi6 octahedra, and edges with two equivalent TeCsBi4 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 1–7°. In the sixth Te2- site, Te2- is bonded to six Bi+2.75+ atoms to form TeBi6 octahedra that share a cornercorner with one TeBi6 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, edges with four TeBi6 octahedra, and edges with three TeCsBi4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°. In the seventh Te2- site, Te2- is bonded to one Cs1+ and four Bi+2.75+ atoms to form distorted TeCsBi4 trigonal bipyramids that share corners with five TeBi6 octahedra, corners with two equivalent TeCsBi4 trigonal bipyramids, and edges with five TeBi6 octahedra. The corner-sharing octahedra tilt angles range from 5–35°. In the eighth Te2- site, Te2- is bonded in a 7-coordinate geometry to three Cs1+, two equivalent Bi+2.75+, and two equivalent Te2- atoms. In the ninth Te2- site, Te2- is bonded in a 7-coordinate geometry to three equivalent Cs1+, two equivalent Bi+2.75+, and two equivalent Te2- atoms. Both Te–Te bond lengths are 3.67 Å. In the tenth Te2- site, Te2- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Bi+2.75+ atoms. In the eleventh Te2- site, Te2- is bonded in a 6-coordinate geometry to four equivalent Cs1+ and two equivalent Bi+2.75+ atoms. In the twelfth Te2- site, Te2- is bonded in a 5-coordinate geometry to five Bi+2.75+ atoms.