Materials Data on Sr(AlSi)2 by Materials Project

Abstract

Al2Si2Sr crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Sr2+ is bonded to six equivalent Si4- atoms to form SrSi6 octahedra that share corners with twelve equivalent AlSi4 tetrahedra, edges with six equivalent SrSi6 octahedra, and edges with six equivalent AlSi4 tetrahedra. All Sr–Si bond lengths are 3.18 Å. Al3+ is bonded to four equivalent Si4- atoms to form AlSi4 tetrahedra that share corners with six equivalent SrSi6 octahedra, corners with six equivalent AlSi4 tetrahedra, edges with three equivalent SrSi6 octahedra, and edges with three equivalent AlSi4 tetrahedra. The corner-sharing octahedra tilt angles range from 24–50°. There are three shorter (2.54 Å) and one longer (2.60 Å) Al–Si bond lengths. Si4- is bonded to three equivalent Sr2+ and four equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing SiSr3Al4 pentagonal bipyramids.