TbCoGa5 crystallizes in the tetragonal P4/mmm space group. Tb(1) is bonded to four equivalent Ga(2) and eight equivalent Ga(1) atoms to form a mixture of face and corner-sharing TbGa12 cuboctahedra. Co(1) is bonded in a body-centered cubic geometry to eight equivalent Ga(1) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 11-coordinate geometry to two equivalent Tb(1), two equivalent Co(1), two equivalent Ga(2), and five equivalent Ga(1) atoms. In the second Ga site, Ga(2) is bonded in a distorted square co-planar geometry to four equivalent Tb(1) and eight equivalent Ga(1) atoms.
TbCoGa5 crystallizes in the tetragonal P4/mmm space group. Tb(1) is bonded to four equivalent Ga(2) and eight equivalent Ga(1) atoms to form a mixture of face and corner-sharing TbGa12 cuboctahedra. All Tb(1)-Ga(2) bond lengths are 2.95 Å. All Tb(1)-Ga(1) bond lengths are 2.97 Å. Co(1) is bonded in a body-centered cubic geometry to eight equivalent Ga(1) atoms. All Co(1)-Ga(1) bond lengths are 2.45 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 11-coordinate geometry to two equivalent Tb(1), two equivalent Co(1), two equivalent Ga(2), and five equivalent Ga(1) atoms. Both Ga(1)-Ga(2) bond lengths are 2.97 Å. There is one shorter (2.55 Å) and four longer (2.95 Å) Ga(1)-Ga(1) bond lengths. In the second Ga site, Ga(2) is bonded in a distorted square co-planar geometry to four equivalent Tb(1) and eight equivalent Ga(1) atoms.