Materials Data on NdAl4Ge2Au by Materials Project

Abstract

NdAuAl4Ge2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Nd is bonded to six equivalent Ge atoms to form NdGe6 octahedra that share corners with twelve AlGe3Au tetrahedra, edges with six equivalent NdGe6 octahedra, and edges with six equivalent AlGe3Au tetrahedra. All Nd–Ge bond lengths are 3.07 Å. Au is bonded in a body-centered cubic geometry to eight Al atoms. There are six shorter (2.59 Å) and two longer (2.61 Å) Au–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to one Au and three equivalent Ge atoms to form AlGe3Au tetrahedra that share corners with three equivalent NdGe6 octahedra, corners with ten AlGe3Au tetrahedra, edges with three equivalent NdGe6 octahedra, and edges with three equivalent AlGeAu3 tetrahedra. The corner-sharing octahedral tilt angles are 18°. All Al–Ge bond lengths are 2.60 Å. In the second Al site, Al is bonded to three equivalent Au and one Ge atom to form distorted AlGeAu3 tetrahedra that share corners with three equivalent NdGe6 octahedra, corners with twelve AlGe3Au tetrahedra, and edges with six AlGe3Au tetrahedra. The corner-sharing octahedral tilt angles are 54°. The Al–Ge bond length is 2.64 Å. Ge is bonded to three equivalent Nd and four Al atoms to form a mixture of distorted edge and corner-sharing GeNd3Al4 pentagonal bipyramids.