CeAuAl4Ge2 crystallizes in the trigonal R-3m space group. Ce(1) is bonded to six equivalent Ge(1) atoms to form CeGe6 octahedra that share corners with six equivalent Al(1)Ge3Au tetrahedra, corners with six equivalent Al(2)GeAu3 tetrahedra, edges with six equivalent Ce(1)Ge6 octahedra, and edges with six equivalent Al(1)Ge3Au tetrahedra. Au(1) is bonded in a body-centered cubic geometry to two equivalent Al(1) and six equivalent Al(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one Au(1) and three equivalent Ge(1) atoms to form AlGe3Au tetrahedra that share corners with three equivalent Ce(1)Ge6 octahedra, corners with three equivalent Al(2)GeAu3 tetrahedra, corners with seven equivalent Al(1)Ge3Au tetrahedra, edges with three equivalent Ce(1)Ge6 octahedra, and edges with three equivalent Al(2)GeAu3 tetrahedra. The corner-sharing octahedral tilt angles are 18°. In the second Al site, Al(2) is bonded to three equivalent Au(1) and one Ge(1) atom to form distorted AlGeAu3 tetrahedra that share corners with three equivalent Ce(1)Ge6 octahedra, corners with three equivalent Al(1)Ge3Au tetrahedra, corners with nine equivalent Al(2)GeAu3 tetrahedra, edges with three equivalent Al(1)Ge3Au tetrahedra, and edges with three equivalent Al(2)GeAu3 tetrahedra. The corner-sharing octahedral tilt angles are 54°. Ge(1) is bonded to three equivalent Ce(1), one Al(2), and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing GeCe3Al4 pentagonal bipyramids.
CeAuAl4Ge2 crystallizes in the trigonal R-3m space group. Ce(1) is bonded to six equivalent Ge(1) atoms to form CeGe6 octahedra that share corners with six equivalent Al(1)Ge3Au tetrahedra, corners with six equivalent Al(2)GeAu3 tetrahedra, edges with six equivalent Ce(1)Ge6 octahedra, and edges with six equivalent Al(1)Ge3Au tetrahedra. All Ce(1)-Ge(1) bond lengths are 3.05 Å. Au(1) is bonded in a body-centered cubic geometry to two equivalent Al(1) and six equivalent Al(2) atoms. Both Au(1)-Al(1) bond lengths are 2.63 Å. All Au(1)-Al(2) bond lengths are 2.59 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one Au(1) and three equivalent Ge(1) atoms to form AlGe3Au tetrahedra that share corners with three equivalent Ce(1)Ge6 octahedra, corners with three equivalent Al(2)GeAu3 tetrahedra, corners with seven equivalent Al(1)Ge3Au tetrahedra, edges with three equivalent Ce(1)Ge6 octahedra, and edges with three equivalent Al(2)GeAu3 tetrahedra. The corner-sharing octahedral tilt angles are 18°. All Al(1)-Ge(1) bond lengths are 2.60 Å. In the second Al site, Al(2) is bonded to three equivalent Au(1) and one Ge(1) atom to form distorted AlGeAu3 tetrahedra that share corners with three equivalent Ce(1)Ge6 octahedra, corners with three equivalent Al(1)Ge3Au tetrahedra, corners with nine equivalent Al(2)GeAu3 tetrahedra, edges with three equivalent Al(1)Ge3Au tetrahedra, and edges with three equivalent Al(2)GeAu3 tetrahedra. The corner-sharing octahedral tilt angles are 54°. The Al(2)-Ge(1) bond length is 2.64 Å. Ge(1) is bonded to three equivalent Ce(1), one Al(2), and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing GeCe3Al4 pentagonal bipyramids.