Ca6Ge2O crystallizes in the cubic Fm-3m space group. Ca(1) is bonded in a single-bond geometry to four equivalent Ge(1) and one O(1) atom. Ge(1) is bonded to twelve equivalent Ca(1) atoms to form GeCa12 cuboctahedra that share corners with twelve equivalent Ge(1)Ca12 cuboctahedra, faces with six equivalent Ge(1)Ca12 cuboctahedra, and faces with four equivalent O(1)Ca6 octahedra. O(1) is bonded to six equivalent Ca(1) atoms to form OCa6 octahedra that share faces with eight equivalent Ge(1)Ca12 cuboctahedra.
Ca6Ge2O crystallizes in the cubic Fm-3m space group. Ca(1) is bonded in a single-bond geometry to four equivalent Ge(1) and one O(1) atom. All Ca(1)-Ge(1) bond lengths are 3.40 Å. The Ca(1)-O(1) bond length is 2.37 Å. Ge(1) is bonded to twelve equivalent Ca(1) atoms to form GeCa12 cuboctahedra that share corners with twelve equivalent Ge(1)Ca12 cuboctahedra, faces with six equivalent Ge(1)Ca12 cuboctahedra, and faces with four equivalent O(1)Ca6 octahedra. O(1) is bonded to six equivalent Ca(1) atoms to form OCa6 octahedra that share faces with eight equivalent Ge(1)Ca12 cuboctahedra.