DOI: 10.17188/1206740
title: Materials Data on Ca(Sm2Se3)4 by Materials Project

description: Ca(Sm2Se3)4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Ca2+ is bonded to eight Se2- atoms to form distorted CaSe8 hexagonal bipyramids that share corners with eight SmSe8 hexagonal bipyramids, edges with four SmSe8 hexagonal bipyramids, and faces with eight SmSe8 hexagonal bipyramids. There are a spread of Ca–Se bond distances ranging from 2.99–3.20 Å. There are eight inequivalent Sm+2.75+ sites. In the first Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven SmSe8 hexagonal bipyramids, an edgeedge with one CaSe8 hexagonal bipyramid, edges with three SmSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.95–3.17 Å. In the second Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven SmSe8 hexagonal bipyramids, edges with four SmSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.96–3.17 Å. In the third Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share corners with two equivalent CaSe8 hexagonal bipyramids, corners with six SmSe8 hexagonal bipyramids, edges with four SmSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.95–3.17 Å. In the fourth Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share corners with two equivalent CaSe8 hexagonal bipyramids, corners with six SmSe8 hexagonal bipyramids, edges with four SmSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.96–3.17 Å. In the fifth Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven SmSe8 hexagonal bipyramids, an edgeedge with one CaSe8 hexagonal bipyramid, edges with three SmSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.98–3.18 Å. In the sixth Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share corners with eight SmSe8 hexagonal bipyramids, edges with two equivalent CaSe8 hexagonal bipyramids, edges with two SmSe8 hexagonal bipyramids, and faces with eight SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.97–3.18 Å. In the seventh Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share a cornercorner with one CaSe8 hexagonal bipyramid, corners with seven SmSe8 hexagonal bipyramids, edges with four SmSe8 hexagonal bipyramids, a faceface with one CaSe8 hexagonal bipyramid, and faces with seven SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.96–3.16 Å. In the eighth Sm+2.75+ site, Sm+2.75+ is bonded to eight Se2- atoms to form distorted SmSe8 hexagonal bipyramids that share corners with eight SmSe8 hexagonal bipyramids, edges with four SmSe8 hexagonal bipyramids, faces with two equivalent CaSe8 hexagonal bipyramids, and faces with six SmSe8 hexagonal bipyramids. There are a spread of Sm–Se bond distances ranging from 2.98–3.18 Å. There are twelve inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six Sm+2.75+ atoms to form a mixture of distorted edge, corner, and face-sharing SeSm6 octahedra. The corner-sharing octahedra tilt angles range from 17–51°. In the second Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form a mixture of distorted edge, corner, and face-sharing SeCaSm5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the third Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeCaSm5 octahedra, and faces with five SeSm6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the fourth Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeSm6 octahedra, and faces with five SeCaSm5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the fifth Se2- site, Se2- is bonded to six Sm+2.75+ atoms to form distorted SeSm6 octahedra that share corners with fifteen SeCaSm5 octahedra, edges with six SeSm6 octahedra, and faces with five SeSm6 octahedra. The corner-sharing octahedra tilt angles range from 17–51°. In the sixth Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeSm6 octahedra, and faces with five SeCaSm5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the seventh Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeSm6 octahedra, and faces with five SeCaSm5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the eighth Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeSm6 octahedra, and faces with five SeCaSm5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the ninth Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeCaSm5 octahedra, and faces with five SeCaSm5 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the tenth Se2- site, Se2- is bonded to six Sm+2.75+ atoms to form distorted SeSm6 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeCaSm5 octahedra, and faces with five SeSm6 octahedra. The corner-sharing octahedra tilt angles range from 16–51°. In the eleventh Se2- site, Se2- is bonded to one Ca2+ and five Sm+2.75+ atoms to form distorted SeCaSm5 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeCaSm5 octahedra, and faces with five SeSm6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°. In the twelfth Se2- site, Se2- is bonded to six Sm+2.75+ atoms to form distorted SeSm6 octahedra that share corners with fifteen SeSm6 octahedra, edges with six SeCaSm5 octahedra, and faces with five SeSm6 octahedra. The corner-sharing octahedra tilt angles range from 16–51°.