CaGaGe crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to six equivalent Ge(1) atoms to form CaGe6 octahedra that share corners with six equivalent Ga(1)Ca3Ge3 octahedra, edges with six equivalent Ca(1)Ge6 octahedra, and edges with six equivalent Ga(1)Ca3Ge3 octahedra. The corner-sharing octahedral tilt angles are 22°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to six equivalent Ga(1) atoms. Ga(1) is bonded to three equivalent Ca(2) and three equivalent Ge(1) atoms to form distorted GaCa3Ge3 octahedra that share corners with three equivalent Ca(1)Ge6 octahedra, corners with six equivalent Ga(1)Ca3Ge3 octahedra, edges with three equivalent Ca(1)Ge6 octahedra, edges with six equivalent Ga(1)Ca3Ge3 octahedra, and  a faceface with one Ga(1)Ca3Ge3 octahedra. The corner-sharing octahedral tilt angles range from 22-48°. Ge(1) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Ga(1) atoms.
CaGaGe crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to six equivalent Ge(1) atoms to form CaGe6 octahedra that share corners with six equivalent Ga(1)Ca3Ge3 octahedra, edges with six equivalent Ca(1)Ge6 octahedra, and edges with six equivalent Ga(1)Ca3Ge3 octahedra. The corner-sharing octahedral tilt angles are 22°. All Ca(1)-Ge(1) bond lengths are 3.11 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to six equivalent Ga(1) atoms. All Ca(2)-Ga(1) bond lengths are 2.97 Å. Ga(1) is bonded to three equivalent Ca(2) and three equivalent Ge(1) atoms to form distorted GaCa3Ge3 octahedra that share corners with three equivalent Ca(1)Ge6 octahedra, corners with six equivalent Ga(1)Ca3Ge3 octahedra, edges with three equivalent Ca(1)Ge6 octahedra, edges with six equivalent Ga(1)Ca3Ge3 octahedra, and  a faceface with one Ga(1)Ca3Ge3 octahedra. The corner-sharing octahedral tilt angles range from 22-48°. All Ga(1)-Ge(1) bond lengths are 2.52 Å. Ge(1) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Ga(1) atoms.