Tb(Co2B)6 crystallizes in the trigonal R-3m space group. Tb(1) is bonded to six equivalent Co(2), twelve equivalent Co(1), and six equivalent B(1) atoms to form distorted edge-sharing TbCo18B6 cuboctahedra. There are two inequivalent Co sites. In the first Co site, Co(2) is bonded in a distorted T-shaped geometry to one Tb(1) and three equivalent B(1) atoms. In the second Co site, Co(1) is bonded in a 4-coordinate geometry to two equivalent Tb(1) and four equivalent B(1) atoms. B(1) is bonded in a 7-coordinate geometry to one Tb(1), three equivalent Co(2), and four equivalent Co(1) atoms.
Tb(Co2B)6 crystallizes in the trigonal R-3m space group. Tb(1) is bonded to six equivalent Co(2), twelve equivalent Co(1), and six equivalent B(1) atoms to form distorted edge-sharing TbCo18B6 cuboctahedra. All Tb(1)-Co(2) bond lengths are 3.07 Å. All Tb(1)-Co(1) bond lengths are 3.21 Å. All Tb(1)-B(1) bond lengths are 3.00 Å. There are two inequivalent Co sites. In the first Co site, Co(2) is bonded in a distorted T-shaped geometry to one Tb(1) and three equivalent B(1) atoms. There is one shorter (2.09 Å) and two longer (2.11 Å) Co(2)-B(1) bond lengths. In the second Co site, Co(1) is bonded in a 4-coordinate geometry to two equivalent Tb(1) and four equivalent B(1) atoms. There are two shorter (2.01 Å) and two longer (2.02 Å) Co(1)-B(1) bond lengths. B(1) is bonded in a 7-coordinate geometry to one Tb(1), three equivalent Co(2), and four equivalent Co(1) atoms.