CaGe2 crystallizes in the trigonal R-3m space group. Ca(1) is bonded in a 7-coordinate geometry to three equivalent Ge(2) and four equivalent Ge(1) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(2) is bonded to three equivalent Ca(1) and three equivalent Ge(2) atoms to form distorted edge-sharing GeCa3Ge3 octahedra. In the second Ge site, Ge(1) is bonded in a 7-coordinate geometry to four equivalent Ca(1) and three equivalent Ge(1) atoms.
CaGe2 crystallizes in the trigonal R-3m space group. Ca(1) is bonded in a 7-coordinate geometry to three equivalent Ge(2) and four equivalent Ge(1) atoms. All Ca(1)-Ge(2) bond lengths are 3.04 Å. There are three shorter (3.11 Å) and one longer (3.18 Å) Ca(1)-Ge(1) bond length. There are two inequivalent Ge sites. In the first Ge site, Ge(2) is bonded to three equivalent Ca(1) and three equivalent Ge(2) atoms to form distorted edge-sharing GeCa3Ge3 octahedra. All Ge(2)-Ge(2) bond lengths are 2.56 Å. In the second Ge site, Ge(1) is bonded in a 7-coordinate geometry to four equivalent Ca(1) and three equivalent Ge(1) atoms. All Ge(1)-Ge(1) bond lengths are 2.60 Å.