Materials Data on Sr(AlGe)2 by Materials Project
Sr(AlGe)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Sr is bonded to six equivalent Ge atoms to form SrGe6 octahedra that share corners with twelve equivalent AlGe4 tetrahedra, edges with six equivalent SrGe6 octahedra, and edges with six equivalent AlGe4 tetrahedra. All Sr–Ge bond lengths are 3.19 Å. Al is bonded to four equivalent Ge atoms to form AlGe4 tetrahedra that share corners with six equivalent SrGe6 octahedra, corners with six equivalent AlGe4 tetrahedra, edges with three equivalent SrGe6 octahedra, and edges with three equivalent AlGe4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–50°. There are three shorter (2.58 Å) and one longer (2.65 Å) Al–Ge bond lengths. Ge is bonded to three equivalent Sr and four equivalent Al atoms to form a mixture of distorted corner and edge-sharing GeSr3Al4 pentagonal bipyramids.