Tb3Ag3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to four equivalent Ga(1) and eight equivalent Ga(2) atoms to form TbGa12 cuboctahedra that share edges with two equivalent Ag(1)Tb4Ga4Ag4 cuboctahedra and faces with two equivalent Tb(1)Ga12 cuboctahedra. In the second Tb site, Tb(2) is bonded in a 14-coordinate geometry to two equivalent Ag(1), two equivalent Ag(2), four equivalent Ga(2), and six equivalent Ga(1) atoms. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded to four equivalent Tb(2), four equivalent Ag(2), and four equivalent Ga(1) atoms to form AgTb4Ga4Ag4 cuboctahedra that share edges with two equivalent Tb(1)Ga12 cuboctahedra and faces with two equivalent Ag(1)Tb4Ga4Ag4 cuboctahedra. In the second Ag site, Ag(2) is bonded in a 10-coordinate geometry to two equivalent Tb(2), two equivalent Ag(1), two equivalent Ga(2), and four equivalent Ga(1) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 10-coordinate geometry to one Tb(1), three equivalent Tb(2), one Ag(1), two equivalent Ag(2), and three equivalent Ga(2) atoms. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Tb(1), two equivalent Tb(2), one Ag(2), one Ga(2), and three equivalent Ga(1) atoms.
Tb3Ag3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to four equivalent Ga(1) and eight equivalent Ga(2) atoms to form TbGa12 cuboctahedra that share edges with two equivalent Ag(1)Tb4Ga4Ag4 cuboctahedra and faces with two equivalent Tb(1)Ga12 cuboctahedra. All Tb(1)-Ga(1) bond lengths are 3.26 Å. All Tb(1)-Ga(2) bond lengths are 3.26 Å. In the second Tb site, Tb(2) is bonded in a 14-coordinate geometry to two equivalent Ag(1), two equivalent Ag(2), four equivalent Ga(2), and six equivalent Ga(1) atoms. Both Tb(2)-Ag(1) bond lengths are 3.45 Å. Both Tb(2)-Ag(2) bond lengths are 3.21 Å. All Tb(2)-Ga(2) bond lengths are 3.10 Å. There are four shorter (3.15 Å) and two longer (3.34 Å) Tb(2)-Ga(1) bond lengths. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded to four equivalent Tb(2), four equivalent Ag(2), and four equivalent Ga(1) atoms to form AgTb4Ga4Ag4 cuboctahedra that share edges with two equivalent Tb(1)Ga12 cuboctahedra and faces with two equivalent Ag(1)Tb4Ga4Ag4 cuboctahedra. All Ag(1)-Ag(2) bond lengths are 2.85 Å. All Ag(1)-Ga(1) bond lengths are 2.80 Å. In the second Ag site, Ag(2) is bonded in a 10-coordinate geometry to two equivalent Tb(2), two equivalent Ag(1), two equivalent Ga(2), and four equivalent Ga(1) atoms. Both Ag(2)-Ga(2) bond lengths are 2.67 Å. All Ag(2)-Ga(1) bond lengths are 2.89 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 10-coordinate geometry to one Tb(1), three equivalent Tb(2), one Ag(1), two equivalent Ag(2), and three equivalent Ga(2) atoms. There are two shorter (2.63 Å) and one longer (2.73 Å) Ga(1)-Ga(2) bond length. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Tb(1), two equivalent Tb(2), one Ag(2), one Ga(2), and three equivalent Ga(1) atoms. The Ga(2)-Ga(2) bond length is 2.52 Å.