Tb3Ga2 crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 4-coordinate geometry to two equivalent Ga(3) and four equivalent Ga(4) atoms. In the second Tb site, Tb(2) is bonded in a 5-coordinate geometry to two equivalent Ga(4) and three equivalent Ga(3) atoms. In the third Tb site, Tb(3) is bonded in a 6-coordinate geometry to one Ga(1), one Ga(2), one Ga(3), and three equivalent Ga(4) atoms. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 8-coordinate geometry to eight equivalent Tb(3) atoms. In the second Ga site, Ga(2) is bonded in a body-centered cubic geometry to eight equivalent Tb(3) atoms. In the third Ga site, Ga(3) is bonded in a 9-coordinate geometry to two equivalent Tb(1), three equivalent Tb(2), and four equivalent Tb(3) atoms. In the fourth Ga site, Ga(4) is bonded in a 10-coordinate geometry to one Tb(2), two equivalent Tb(1), six equivalent Tb(3), and one Ga(4) atom.
Tb3Ga2 crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 4-coordinate geometry to two equivalent Ga(3) and four equivalent Ga(4) atoms. Both Tb(1)-Ga(3) bond lengths are 2.92 Å. There are two shorter (3.05 Å) and two longer (3.70 Å) Tb(1)-Ga(4) bond lengths. In the second Tb site, Tb(2) is bonded in a 5-coordinate geometry to two equivalent Ga(4) and three equivalent Ga(3) atoms. Both Tb(2)-Ga(4) bond lengths are 3.00 Å. There are two shorter (3.37 Å) and one longer (3.55 Å) Tb(2)-Ga(3) bond length. In the third Tb site, Tb(3) is bonded in a 6-coordinate geometry to one Ga(1), one Ga(2), one Ga(3), and three equivalent Ga(4) atoms. The Tb(3)-Ga(1) bond length is 3.01 Å. The Tb(3)-Ga(2) bond length is 3.20 Å. The Tb(3)-Ga(3) bond length is 2.97 Å. There are a spread of Tb(3)-Ga(4) bond distances ranging from 3.08-3.34 Å. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 8-coordinate geometry to eight equivalent Tb(3) atoms. In the second Ga site, Ga(2) is bonded in a body-centered cubic geometry to eight equivalent Tb(3) atoms. In the third Ga site, Ga(3) is bonded in a 9-coordinate geometry to two equivalent Tb(1), three equivalent Tb(2), and four equivalent Tb(3) atoms. In the fourth Ga site, Ga(4) is bonded in a 10-coordinate geometry to one Tb(2), two equivalent Tb(1), six equivalent Tb(3), and one Ga(4) atom. The Ga(4)-Ga(4) bond length is 2.77 Å.