Tb3Co2Ge4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to two equivalent Ge(1) and six equivalent Ge(2) atoms. In the second Tb site, Tb(2) is bonded in a 12-coordinate geometry to four equivalent Co(1), three equivalent Ge(2), and five equivalent Ge(1) atoms. Co(1) is bonded in a 8-coordinate geometry to four equivalent Tb(2), one Ge(2), and three equivalent Ge(1) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 10-coordinate geometry to one Tb(1), five equivalent Tb(2), three equivalent Co(1), and one Ge(1) atom. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Tb(1), three equivalent Tb(2), one Co(1), and two equivalent Ge(2) atoms.
Tb3Co2Ge4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to two equivalent Ge(1) and six equivalent Ge(2) atoms. Both Tb(1)-Ge(1) bond lengths are 3.07 Å. There are four shorter (2.99 Å) and two longer (3.38 Å) Tb(1)-Ge(2) bond lengths. In the second Tb site, Tb(2) is bonded in a 12-coordinate geometry to four equivalent Co(1), three equivalent Ge(2), and five equivalent Ge(1) atoms. There are a spread of Tb(2)-Co(1) bond distances ranging from 2.90-3.27 Å. All Tb(2)-Ge(2) bond lengths are 2.99 Å. There are a spread of Tb(2)-Ge(1) bond distances ranging from 3.09-3.29 Å. Co(1) is bonded in a 8-coordinate geometry to four equivalent Tb(2), one Ge(2), and three equivalent Ge(1) atoms. The Co(1)-Ge(2) bond length is 2.41 Å. There are two shorter (2.35 Å) and one longer (2.43 Å) Co(1)-Ge(1) bond length. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 10-coordinate geometry to one Tb(1), five equivalent Tb(2), three equivalent Co(1), and one Ge(1) atom. The Ge(1)-Ge(1) bond length is 3.05 Å. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Tb(1), three equivalent Tb(2), one Co(1), and two equivalent Ge(2) atoms. Both Ge(2)-Ge(2) bond lengths are 2.74 Å.