Materials Data on Sm3AlFeS7 by Materials Project

Abstract

Sm3FeAlS7 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. Sm3+ is bonded to seven S2- atoms to form distorted SmS7 pentagonal bipyramids that share a cornercorner with one FeS6 octahedra, corners with six equivalent SmS7 pentagonal bipyramids, corners with two equivalent AlS4 tetrahedra, an edgeedge with one FeS6 octahedra, edges with four equivalent SmS7 pentagonal bipyramids, an edgeedge with one AlS4 tetrahedra, and a faceface with one FeS6 octahedra. The corner-sharing octahedral tilt angles are 24°. There are a spread of Sm–S bond distances ranging from 2.83–3.01 Å. Fe2+ is bonded to six equivalent S2- atoms to form FeS6 octahedra that share corners with three equivalent SmS7 pentagonal bipyramids, edges with three equivalent SmS7 pentagonal bipyramids, faces with two equivalent FeS6 octahedra, and faces with three equivalent SmS7 pentagonal bipyramids. There are three shorter (2.46 Å) and three longer (2.56 Å) Fe–S bond lengths. Al3+ is bonded to four S2- atoms to form AlS4 tetrahedra that share corners with six equivalent SmS7 pentagonal bipyramids and edges with three equivalent SmS7 pentagonal bipyramids. There are one shorter (2.24 Å) and three longer (2.26 Å) Al–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Sm3+ and two equivalent Fe2+ atoms to form distorted SSm3Fe2 square pyramids that share corners with two equivalent SSm3Fe2 square pyramids, corners with three equivalent SSm3Al tetrahedra, edges with four equivalent SSm3Fe2 square pyramids, and faces with two equivalent SSm3Fe2 square pyramids. In the second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Sm3+ and one Al3+ atom. In the third S2- site, S2- is bonded to three equivalent Sm3+ and one Al3+ atom to form distorted corner-sharing SSm3Al tetrahedra.