Co3Ge2 crystallizes in the hexagonal P-6m2 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 11-coordinate geometry to two equivalent Co(1), three equivalent Co(2), three equivalent Ge(1), and three equivalent Ge(2) atoms. In the second Co site, Co(2) is bonded to six equivalent Co(1), two equivalent Ge(1), and three equivalent Ge(2) atoms to form a mixture of distorted corner and face-sharing CoCo6Ge5 trigonal bipyramids. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to two equivalent Co(2) and six equivalent Co(1) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Co(2) and six equivalent Co(1) atoms.
Co3Ge2 crystallizes in the hexagonal P-6m2 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 11-coordinate geometry to two equivalent Co(1), three equivalent Co(2), three equivalent Ge(1), and three equivalent Ge(2) atoms. There is one shorter (2.35 Å) and one longer (2.49 Å) Co(1)-Co(1) bond length. All Co(1)-Co(2) bond lengths are 2.58 Å. All Co(1)-Ge(1) bond lengths are 2.54 Å. All Co(1)-Ge(2) bond lengths are 2.58 Å. In the second Co site, Co(2) is bonded to six equivalent Co(1), two equivalent Ge(1), and three equivalent Ge(2) atoms to form a mixture of distorted corner and face-sharing CoCo6Ge5 trigonal bipyramids. Both Co(2)-Ge(1) bond lengths are 2.42 Å. All Co(2)-Ge(2) bond lengths are 2.25 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to two equivalent Co(2) and six equivalent Co(1) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Co(2) and six equivalent Co(1) atoms.