Ir3Cr crystallizes in the trigonal R-3m space group. Cr(1) is bonded to six equivalent Ir(1) atoms to form distorted CrIr6 cuboctahedra that share corners with six equivalent Ir(2)Ir12 cuboctahedra, edges with six equivalent Cr(1)Ir6 cuboctahedra, and edges with six equivalent Ir(2)Ir12 cuboctahedra. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to three equivalent Cr(1) and three equivalent Ir(2) atoms to form distorted IrCr3Ir3 cuboctahedra that share corners with six equivalent Ir(1)Cr3Ir3 cuboctahedra, corners with six equivalent Ir(2)Ir12 cuboctahedra, edges with six equivalent Ir(2)Ir12 cuboctahedra, and edges with twelve equivalent Ir(1)Cr3Ir3 cuboctahedra. In the second Ir site, Ir(2) is bonded to six equivalent Ir(1) and six equivalent Ir(2) atoms to form IrIr12 cuboctahedra that share corners with six equivalent Cr(1)Ir6 cuboctahedra, corners with six equivalent Ir(2)Ir12 cuboctahedra, corners with twelve equivalent Ir(1)Cr3Ir3 cuboctahedra, edges with six equivalent Cr(1)Ir6 cuboctahedra, edges with six equivalent Ir(2)Ir12 cuboctahedra, edges with twelve equivalent Ir(1)Cr3Ir3 cuboctahedra, and faces with six equivalent Ir(2)Ir12 cuboctahedra.
Ir3Cr crystallizes in the trigonal R-3m space group. Cr(1) is bonded to six equivalent Ir(1) atoms to form distorted CrIr6 cuboctahedra that share corners with six equivalent Ir(2)Ir12 cuboctahedra, edges with six equivalent Cr(1)Ir6 cuboctahedra, and edges with six equivalent Ir(2)Ir12 cuboctahedra. All Cr(1)-Ir(1) bond lengths are 2.60 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to three equivalent Cr(1) and three equivalent Ir(2) atoms to form distorted IrCr3Ir3 cuboctahedra that share corners with six equivalent Ir(1)Cr3Ir3 cuboctahedra, corners with six equivalent Ir(2)Ir12 cuboctahedra, edges with six equivalent Ir(2)Ir12 cuboctahedra, and edges with twelve equivalent Ir(1)Cr3Ir3 cuboctahedra. All Ir(1)-Ir(2) bond lengths are 2.80 Å. In the second Ir site, Ir(2) is bonded to six equivalent Ir(1) and six equivalent Ir(2) atoms to form IrIr12 cuboctahedra that share corners with six equivalent Cr(1)Ir6 cuboctahedra, corners with six equivalent Ir(2)Ir12 cuboctahedra, corners with twelve equivalent Ir(1)Cr3Ir3 cuboctahedra, edges with six equivalent Cr(1)Ir6 cuboctahedra, edges with six equivalent Ir(2)Ir12 cuboctahedra, edges with twelve equivalent Ir(1)Cr3Ir3 cuboctahedra, and faces with six equivalent Ir(2)Ir12 cuboctahedra. All Ir(2)-Ir(2) bond lengths are 2.71 Å.