Materials Data on Er(AlGe)2 by Materials Project

Abstract

Al2ErGe2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Er is bonded to six equivalent Ge atoms to form distorted ErGe6 octahedra that share corners with twelve equivalent AlGe4 tetrahedra, edges with six equivalent ErGe6 octahedra, and edges with six equivalent AlGe4 tetrahedra. All Er–Ge bond lengths are 2.98 Å. Al is bonded to four equivalent Ge atoms to form distorted AlGe4 tetrahedra that share corners with six equivalent ErGe6 octahedra, corners with six equivalent AlGe4 tetrahedra, edges with three equivalent ErGe6 octahedra, and edges with three equivalent AlGe4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–56°. There are three shorter (2.55 Å) and one longer (2.57 Å) Al–Ge bond lengths. Ge is bonded to three equivalent Er and four equivalent Al atoms to form a mixture of distorted corner and edge-sharing GeEr3Al4 pentagonal bipyramids.