Ta3Co5B2 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a body-centered cubic geometry to eight equivalent Co(2) atoms. In the second Ta site, Ta(2) is bonded in a 13-coordinate geometry to two equivalent Co(1), eight equivalent Co(2), and three equivalent B(1) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to four equivalent Ta(2), four equivalent Co(2), and four equivalent B(1) atoms to form distorted face-sharing CoTa4Co4B4 cuboctahedra. In the second Co site, Co(2) is bonded in a 12-coordinate geometry to two equivalent Ta(1), four equivalent Ta(2), one Co(1), three equivalent Co(2), and two equivalent B(1) atoms. B(1) is bonded in a 9-coordinate geometry to three equivalent Ta(2), two equivalent Co(1), and four equivalent Co(2) atoms.
Ta3Co5B2 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a body-centered cubic geometry to eight equivalent Co(2) atoms. All Ta(1)-Co(2) bond lengths are 2.53 Å. In the second Ta site, Ta(2) is bonded in a 13-coordinate geometry to two equivalent Co(1), eight equivalent Co(2), and three equivalent B(1) atoms. Both Ta(2)-Co(1) bond lengths are 2.64 Å. There are four shorter (2.72 Å) and four longer (2.76 Å) Ta(2)-Co(2) bond lengths. There is one shorter (2.46 Å) and two longer (2.51 Å) Ta(2)-B(1) bond lengths. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to four equivalent Ta(2), four equivalent Co(2), and four equivalent B(1) atoms to form distorted face-sharing CoTa4Co4B4 cuboctahedra. All Co(1)-Co(2) bond lengths are 2.42 Å. All Co(1)-B(1) bond lengths are 2.15 Å. In the second Co site, Co(2) is bonded in a 12-coordinate geometry to two equivalent Ta(1), four equivalent Ta(2), one Co(1), three equivalent Co(2), and two equivalent B(1) atoms. There is one shorter (2.49 Å) and two longer (2.74 Å) Co(2)-Co(2) bond lengths. Both Co(2)-B(1) bond lengths are 2.15 Å. B(1) is bonded in a 9-coordinate geometry to three equivalent Ta(2), two equivalent Co(1), and four equivalent Co(2) atoms.