Materials Data on Ca(AlSn)2 by Materials Project

Abstract

Ca(AlSn)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ca is bonded to six equivalent Sn atoms to form CaSn6 octahedra that share corners with twelve equivalent AlSn4 tetrahedra, edges with six equivalent CaSn6 octahedra, and edges with six equivalent AlSn4 tetrahedra. All Ca–Sn bond lengths are 3.25 Å. Al is bonded to four equivalent Sn atoms to form AlSn4 tetrahedra that share corners with six equivalent CaSn6 octahedra, corners with six equivalent AlSn4 tetrahedra, edges with three equivalent CaSn6 octahedra, and edges with three equivalent AlSn4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–54°. There are three shorter (2.76 Å) and one longer (2.83 Å) Al–Sn bond lengths. Sn is bonded to three equivalent Ca and four equivalent Al atoms to form a mixture of distorted edge and corner-sharing SnCa3Al4 pentagonal bipyramids.