DOE OSTI2020
Sm3CrS6 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are three inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sm–S bond distances ranging from 2.82–3.04 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sm–S bond distances ranging from 2.82–3.10 Å. In the third Sm3+ site, Sm3+ is bonded to seven S2- atoms to form distorted SmS7 pentagonal bipyramids that share a cornercorner with one CrS6 octahedra, edges with two equivalent CrS6 octahedra, and edges with two equivalent SmS7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are a spread of Sm–S bond distances ranging from 2.77–2.90 Å. There are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six S2- atoms to form CrS6 octahedra that share edges with two equivalent CrS6 octahedra and edges with four equivalent SmS7 pentagonal bipyramids. There are two shorter (2.41 Å) and four longer (2.49 Å) Cr–S bond lengths. In the second Cr3+ site, Cr3+ is bonded to six S2- atoms to form CrS6 octahedra that share corners with two equivalent SmS7 pentagonal bipyramids and edges with two equivalent CrS6 octahedra. There are two shorter (2.35 Å) and four longer (2.51 Å) Cr–S bond lengths. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to five Sm3+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to three Sm3+ and two equivalent Cr3+ atoms. In the third S2- site, S2- is bonded to three Sm3+ and one Cr3+ atom to form distorted SSm3Cr trigonal pyramids that share corners with four SSm5 trigonal bipyramids, corners with three equivalent SSm3Cr trigonal pyramids, and a faceface with one SSm5 trigonal bipyramid. In the fourth S2- site, S2- is bonded to five Sm3+ atoms to form distorted SSm5 trigonal bipyramids that share corners with four equivalent SSm4Cr trigonal bipyramids, corners with two equivalent SSm3Cr trigonal pyramids, edges with three SSm5 trigonal bipyramids, and a faceface with one SSm3Cr trigonal pyramid. In the fifth S2- site, S2- is bonded to four Sm3+ and one Cr3+ atom to form distorted SSm4Cr trigonal bipyramids that share corners with five SSm5 trigonal bipyramids, corners with two equivalent SSm3Cr trigonal pyramids, and edges with three SSm5 trigonal bipyramids. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to three Sm3+ and two equivalent Cr3+ atoms.