CaAl2Ge2 crystallizes in the trigonal P-3m1 space group. Ca(1) is bonded to six equivalent Ge(1) atoms to form CaGe6 octahedra that share corners with twelve equivalent Al(1)Ge4 tetrahedra, edges with six equivalent Ca(1)Ge6 octahedra, and edges with six equivalent Al(1)Ge4 tetrahedra. Al(1) is bonded to four equivalent Ge(1) atoms to form AlGe4 tetrahedra that share corners with six equivalent Ca(1)Ge6 octahedra, corners with six equivalent Al(1)Ge4 tetrahedra, edges with three equivalent Ca(1)Ge6 octahedra, and edges with three equivalent Al(1)Ge4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-52°. Ge(1) is bonded to three equivalent Ca(1) and four equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing GeCa3Al4 pentagonal bipyramids.
CaAl2Ge2 crystallizes in the trigonal P-3m1 space group. Ca(1) is bonded to six equivalent Ge(1) atoms to form CaGe6 octahedra that share corners with twelve equivalent Al(1)Ge4 tetrahedra, edges with six equivalent Ca(1)Ge6 octahedra, and edges with six equivalent Al(1)Ge4 tetrahedra. All Ca(1)-Ge(1) bond lengths are 3.05 Å. Al(1) is bonded to four equivalent Ge(1) atoms to form AlGe4 tetrahedra that share corners with six equivalent Ca(1)Ge6 octahedra, corners with six equivalent Al(1)Ge4 tetrahedra, edges with three equivalent Ca(1)Ge6 octahedra, and edges with three equivalent Al(1)Ge4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-52°. There are three shorter (2.53 Å) and one longer (2.62 Å) Al(1)-Ge(1) bond length. Ge(1) is bonded to three equivalent Ca(1) and four equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing GeCa3Al4 pentagonal bipyramids.