GdIr3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 12-coordinate geometry to three equivalent Ir(2), three equivalent Ir(4), and six equivalent Ir(1) atoms. In the second Gd site, Gd(2) is bonded in a distorted hexagonal planar geometry to four equivalent Ir(2), six equivalent Ir(3), and eight equivalent Ir(1) atoms. There are four inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to two equivalent Gd(2), three equivalent Gd(1), one Ir(4), two equivalent Ir(1), two equivalent Ir(2), and two equivalent Ir(3) atoms to form distorted IrGd5Ir7 cuboctahedra that share corners with two equivalent Ir(4)Gd6Ir6 cuboctahedra, corners with four equivalent Ir(2)Gd5Ir7 cuboctahedra, corners with eleven equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with two equivalent Ir(2)Gd5Ir7 cuboctahedra, edges with six equivalent Ir(1)Gd5Ir7 cuboctahedra, faces with three equivalent Ir(4)Gd6Ir6 cuboctahedra, faces with five equivalent Ir(2)Gd5Ir7 cuboctahedra, and faces with six equivalent Ir(1)Gd5Ir7 cuboctahedra. In the second Ir site, Ir(2) is bonded to two equivalent Gd(2), three equivalent Gd(1), one Ir(4), two equivalent Ir(3), and four equivalent Ir(1) atoms to form distorted IrGd5Ir7 cuboctahedra that share corners with two equivalent Ir(4)Gd6Ir6 cuboctahedra, corners with seven equivalent Ir(2)Gd5Ir7 cuboctahedra, corners with eight equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with four equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with four equivalent Ir(2)Gd5Ir7 cuboctahedra,  a faceface with one Ir(2)Gd5Ir7 cuboctahedra, faces with three equivalent Ir(4)Gd6Ir6 cuboctahedra, and faces with ten equivalent Ir(1)Gd5Ir7 cuboctahedra. In the third Ir site, Ir(3) is bonded in a 9-coordinate geometry to three equivalent Gd(2), two equivalent Ir(2), and four equivalent Ir(1) atoms. In the fourth Ir site, Ir(4) is bonded to six equivalent Gd(1), two equivalent Ir(2), and four equivalent Ir(1) atoms to form IrGd6Ir6 cuboctahedra that share corners with four equivalent Ir(2)Gd5Ir7 cuboctahedra, corners with eight equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with six equivalent Ir(4)Gd6Ir6 cuboctahedra, faces with six equivalent Ir(2)Gd5Ir7 cuboctahedra, and faces with twelve equivalent Ir(1)Gd5Ir7 cuboctahedra.
GdIr3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded in a 12-coordinate geometry to three equivalent Ir(2), three equivalent Ir(4), and six equivalent Ir(1) atoms. There are two shorter (3.07 Å) and one longer (3.33 Å) Gd(1)-Ir(2) bond length. There is one shorter (3.16 Å) and two longer (3.17 Å) Gd(1)-Ir(4) bond lengths. There are a spread of Gd(1)-Ir(1) bond distances ranging from 3.07-3.34 Å. In the second Gd site, Gd(2) is bonded in a distorted hexagonal planar geometry to four equivalent Ir(2), six equivalent Ir(3), and eight equivalent Ir(1) atoms. All Gd(2)-Ir(2) bond lengths are 3.43 Å. All Gd(2)-Ir(3) bond lengths are 3.08 Å. There are four shorter (3.42 Å) and four longer (3.44 Å) Gd(2)-Ir(1) bond lengths. There are four inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to two equivalent Gd(2), three equivalent Gd(1), one Ir(4), two equivalent Ir(1), two equivalent Ir(2), and two equivalent Ir(3) atoms to form distorted IrGd5Ir7 cuboctahedra that share corners with two equivalent Ir(4)Gd6Ir6 cuboctahedra, corners with four equivalent Ir(2)Gd5Ir7 cuboctahedra, corners with eleven equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with two equivalent Ir(2)Gd5Ir7 cuboctahedra, edges with six equivalent Ir(1)Gd5Ir7 cuboctahedra, faces with three equivalent Ir(4)Gd6Ir6 cuboctahedra, faces with five equivalent Ir(2)Gd5Ir7 cuboctahedra, and faces with six equivalent Ir(1)Gd5Ir7 cuboctahedra. The Ir(1)-Ir(4) bond length is 2.71 Å. There is one shorter (2.64 Å) and one longer (2.70 Å) Ir(1)-Ir(1) bond length. There is one shorter (2.66 Å) and one longer (2.68 Å) Ir(1)-Ir(2) bond length. There is one shorter (2.63 Å) and one longer (2.66 Å) Ir(1)-Ir(3) bond length. In the second Ir site, Ir(2) is bonded to two equivalent Gd(2), three equivalent Gd(1), one Ir(4), two equivalent Ir(3), and four equivalent Ir(1) atoms to form distorted IrGd5Ir7 cuboctahedra that share corners with two equivalent Ir(4)Gd6Ir6 cuboctahedra, corners with seven equivalent Ir(2)Gd5Ir7 cuboctahedra, corners with eight equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with four equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with four equivalent Ir(2)Gd5Ir7 cuboctahedra,  a faceface with one Ir(2)Gd5Ir7 cuboctahedra, faces with three equivalent Ir(4)Gd6Ir6 cuboctahedra, and faces with ten equivalent Ir(1)Gd5Ir7 cuboctahedra. The Ir(2)-Ir(4) bond length is 2.72 Å. There is one shorter (2.63 Å) and one longer (2.67 Å) Ir(2)-Ir(3) bond length. In the third Ir site, Ir(3) is bonded in a 9-coordinate geometry to three equivalent Gd(2), two equivalent Ir(2), and four equivalent Ir(1) atoms. In the fourth Ir site, Ir(4) is bonded to six equivalent Gd(1), two equivalent Ir(2), and four equivalent Ir(1) atoms to form IrGd6Ir6 cuboctahedra that share corners with four equivalent Ir(2)Gd5Ir7 cuboctahedra, corners with eight equivalent Ir(1)Gd5Ir7 cuboctahedra, edges with six equivalent Ir(4)Gd6Ir6 cuboctahedra, faces with six equivalent Ir(2)Gd5Ir7 cuboctahedra, and faces with twelve equivalent Ir(1)Gd5Ir7 cuboctahedra.