Materials Data on Eu(AlGe)2 by Materials Project
EuAl2Ge2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Eu is bonded to six equivalent Ge atoms to form EuGe6 octahedra that share corners with twelve equivalent AlGe4 tetrahedra, edges with six equivalent EuGe6 octahedra, and edges with six equivalent AlGe4 tetrahedra. All Eu–Ge bond lengths are 3.10 Å. Al is bonded to four equivalent Ge atoms to form AlGe4 tetrahedra that share corners with six equivalent EuGe6 octahedra, corners with six equivalent AlGe4 tetrahedra, edges with three equivalent EuGe6 octahedra, and edges with three equivalent AlGe4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–52°. There are three shorter (2.57 Å) and one longer (2.63 Å) Al–Ge bond lengths. Ge is bonded to three equivalent Eu and four equivalent Al atoms to form a mixture of distorted corner and edge-sharing GeEu3Al4 pentagonal bipyramids.