Er3Ir3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to four equivalent Ga(1) and eight equivalent Ga(2) atoms to form distorted face-sharing ErGa12 cuboctahedra. In the second Er site, Er(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 Er(2) and four equivalent Ga(1) atoms. In the second Ir site, Ir(2) is bonded in a 8-coordinate geometry to two equivalent Er(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 Er(1), two equivalent Er(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 Er(1), two equivalent Er(2), one Ir(2), one Ga(2), and three equivalent Ga(1) atoms.
Er3Ir3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to four equivalent Ga(1) and eight equivalent Ga(2) atoms to form distorted face-sharing ErGa12 cuboctahedra. All Er(1)-Ga(1) bond lengths are 3.23 Å. All Er(1)-Ga(2) bond lengths are 3.18 Å. In the second Er site, Er(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 Er(2)-Ir(1) bond lengths are 2.96 Å. Both Er(2)-Ir(2) bond lengths are 2.99 Å. All Er(2)-Ga(1) bond lengths are 3.03 Å. All Er(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 Er(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 Er(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 Er(1), two equivalent Er(2), one Ir(1), two equivalent Ir(2), and three equivalent Ga(2) atoms. There are two shorter (2.67 Å) and one longer (2.69 Å) Ga(1)-Ga(2) bond length. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(2), one Ir(2), one Ga(2), and three equivalent Ga(1) atoms. The Ga(2)-Ga(2) bond length is 2.54 Å.