ErIrGe2 crystallizes in the orthorhombic Immm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 15-coordinate geometry to six equivalent Ir(1), one Ge(3), two equivalent Ge(2), and six equivalent Ge(1) atoms. In the second Er site, Er(2) is bonded in a 14-coordinate geometry to four equivalent Ir(1), two equivalent Ge(1), four equivalent Ge(2), and four equivalent Ge(3) atoms. Ir(1) is bonded in a 10-coordinate geometry to two equivalent Er(2), three equivalent Er(1), one Ge(2), one Ge(3), and three equivalent Ge(1) atoms. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Er(2), three equivalent Er(1), three equivalent Ir(1), and one Ge(1) atom. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), four equivalent Er(2), two equivalent Ir(1), and one Ge(2) atom. In the third Ge site, Ge(3) is bonded in a 2-coordinate geometry to one Er(1), four equivalent Er(2), and two equivalent Ir(1) atoms.
ErIrGe2 crystallizes in the orthorhombic Immm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 15-coordinate geometry to six equivalent Ir(1), one Ge(3), two equivalent Ge(2), and six equivalent Ge(1) atoms. There are four shorter (3.21 Å) and two longer (3.25 Å) Er(1)-Ir(1) bond lengths. The Er(1)-Ge(3) bond length is 3.48 Å. Both Er(1)-Ge(2) bond lengths are 2.96 Å. There are four shorter (2.92 Å) and two longer (3.05 Å) Er(1)-Ge(1) bond lengths. In the second Er site, Er(2) is bonded in a 14-coordinate geometry to four equivalent Ir(1), two equivalent Ge(1), four equivalent Ge(2), and four equivalent Ge(3) atoms. All Er(2)-Ir(1) bond lengths are 3.14 Å. Both Er(2)-Ge(1) bond lengths are 3.36 Å. All Er(2)-Ge(2) bond lengths are 3.23 Å. All Er(2)-Ge(3) bond lengths are 3.35 Å. Ir(1) is bonded in a 10-coordinate geometry to two equivalent Er(2), three equivalent Er(1), one Ge(2), one Ge(3), and three equivalent Ge(1) atoms. The Ir(1)-Ge(2) bond length is 2.46 Å. The Ir(1)-Ge(3) bond length is 2.45 Å. There are two shorter (2.45 Å) and one longer (2.61 Å) Ir(1)-Ge(1) bond length. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Er(2), three equivalent Er(1), three equivalent Ir(1), and one Ge(1) atom. The Ge(1)-Ge(1) bond length is 2.69 Å. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), four equivalent Er(2), two equivalent Ir(1), and one Ge(2) atom. The Ge(2)-Ge(2) bond length is 2.44 Å. In the third Ge site, Ge(3) is bonded in a 2-coordinate geometry to one Er(1), four equivalent Er(2), and two equivalent Ir(1) atoms.