CoGe crystallizes in the monoclinic C2/m space group. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 4-coordinate geometry to two equivalent Co(2) and two equivalent Ge(2) atoms. In the second Co site, Co(2) is bonded to two equivalent Co(1), two equivalent Ge(1), and two equivalent Ge(2) atoms to form distorted corner-sharing CoCo2Ge4 octahedra. The corner-sharing octahedra are not tilted. In the third Co site, Co(3) is bonded in a 2-coordinate geometry to two equivalent Ge(1) and four equivalent Ge(2) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 3-coordinate geometry to one Co(2), two equivalent Co(3), and two equivalent Ge(2) atoms. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Co(1), one Co(2), four equivalent Co(3), and two equivalent Ge(1) atoms.
CoGe crystallizes in the monoclinic C2/m space group. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 4-coordinate geometry to two equivalent Co(2) and two equivalent Ge(2) atoms. Both Co(1)-Co(2) bond lengths are 2.21 Å. Both Co(1)-Ge(2) bond lengths are 2.42 Å. In the second Co site, Co(2) is bonded to two equivalent Co(1), two equivalent Ge(1), and two equivalent Ge(2) atoms to form distorted corner-sharing CoCo2Ge4 octahedra. The corner-sharing octahedra are not tilted. Both Co(2)-Ge(1) bond lengths are 2.28 Å. Both Co(2)-Ge(2) bond lengths are 2.35 Å. In the third Co site, Co(3) is bonded in a 2-coordinate geometry to two equivalent Ge(1) and four equivalent Ge(2) atoms. Both Co(3)-Ge(1) bond lengths are 2.34 Å. There are two shorter (2.86 Å) and two longer (2.89 Å) Co(3)-Ge(2) bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 3-coordinate geometry to one Co(2), two equivalent Co(3), and two equivalent Ge(2) atoms. Both Ge(1)-Ge(2) bond lengths are 2.56 Å. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Co(1), one Co(2), four equivalent Co(3), and two equivalent Ge(1) atoms.