Tm3Ir3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to four equivalent Ga(1) and eight equivalent Ga(2) atoms to form distorted face-sharing TmGa12 cuboctahedra. In the second Tm site, Tm(2) is bonded in a 12-coordinate geometry to two equivalent Ir(1), two equivalent Ir(2), four equivalent Ga(1), and four equivalent Ga(2) atoms. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 8-coordinate geometry to four equivalent Tm(2) and four equivalent Ga(1) atoms. In the second Ir site, Ir(2) is bonded in a 8-coordinate geometry to two equivalent Tm(2), 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 9-coordinate geometry to one Tm(1), two equivalent Tm(2), one Ir(1), two equivalent Ir(2), and three equivalent Ga(2) atoms. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Tm(1), two equivalent Tm(2), one Ir(2), one Ga(2), and three equivalent Ga(1) atoms.
Tm3Ir3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to four equivalent Ga(1) and eight equivalent Ga(2) atoms to form distorted face-sharing TmGa12 cuboctahedra. All Tm(1)-Ga(1) bond lengths are 3.25 Å. All Tm(1)-Ga(2) bond lengths are 3.16 Å. In the second Tm site, Tm(2) is bonded in a 12-coordinate geometry to two equivalent Ir(1), two equivalent Ir(2), four equivalent Ga(1), and four equivalent Ga(2) atoms. Both Tm(2)-Ir(1) bond lengths are 2.96 Å. Both Tm(2)-Ir(2) bond lengths are 2.98 Å. All Tm(2)-Ga(1) bond lengths are 3.03 Å. All Tm(2)-Ga(2) bond lengths are 3.16 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 8-coordinate geometry to four equivalent Tm(2) and four equivalent Ga(1) atoms. All Ir(1)-Ga(1) bond lengths are 2.62 Å. In the second Ir site, Ir(2) is bonded in a 8-coordinate geometry to two equivalent Tm(2), two equivalent Ga(2), and four equivalent Ga(1) atoms. Both Ir(2)-Ga(2) bond lengths are 2.56 Å. All Ir(2)-Ga(1) bond lengths are 2.60 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 9-coordinate geometry to one Tm(1), two equivalent Tm(2), one Ir(1), two equivalent Ir(2), and three equivalent Ga(2) atoms. There are two shorter (2.67 Å) and one longer (2.68 Å) Ga(1)-Ga(2) bond length. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Tm(1), two equivalent Tm(2), one Ir(2), one Ga(2), and three equivalent Ga(1) atoms. The Ga(2)-Ga(2) bond length is 2.53 Å.