Materials Data on Sm(AlSi)2 by Materials Project

Abstract

Al2Si2Sm crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Sm2+ is bonded to six equivalent Si4- atoms to form SmSi6 octahedra that share corners with twelve equivalent AlSi4 tetrahedra, edges with six equivalent SmSi6 octahedra, and edges with six equivalent AlSi4 tetrahedra. All Sm–Si bond lengths are 3.02 Å. Al3+ is bonded to four equivalent Si4- atoms to form AlSi4 tetrahedra that share corners with six equivalent SmSi6 octahedra, corners with six equivalent AlSi4 tetrahedra, edges with three equivalent SmSi6 octahedra, and edges with three equivalent AlSi4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–54°. There are three shorter (2.52 Å) and one longer (2.53 Å) Al–Si bond lengths. Si4- is bonded to three equivalent Sm2+ and four equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing SiSm3Al4 pentagonal bipyramids.