DOE OSTI2020
Ir3Rh is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded to eight Ir and four equivalent Rh atoms to form IrIr8Rh4 cuboctahedra that share corners with twelve equivalent IrIr8Rh4 cuboctahedra, edges with eight equivalent RhIr12 cuboctahedra, edges with sixteen IrIr8Rh4 cuboctahedra, faces with four equivalent RhIr12 cuboctahedra, and faces with fourteen IrIr8Rh4 cuboctahedra. All Ir–Ir bond lengths are 2.74 Å. All Ir–Rh bond lengths are 2.74 Å. In the second Ir site, Ir is bonded to eight equivalent Ir and four equivalent Rh atoms to form IrIr8Rh4 cuboctahedra that share corners with four equivalent IrIr8Rh4 cuboctahedra, corners with eight equivalent RhIr12 cuboctahedra, edges with twenty-four IrIr8Rh4 cuboctahedra, faces with six equivalent RhIr12 cuboctahedra, and faces with twelve IrIr8Rh4 cuboctahedra. All Ir–Rh bond lengths are 2.74 Å. Rh is bonded to twelve Ir atoms to form RhIr12 cuboctahedra that share corners with four equivalent RhIr12 cuboctahedra, corners with eight equivalent IrIr8Rh4 cuboctahedra, edges with eight equivalent RhIr12 cuboctahedra, edges with sixteen equivalent IrIr8Rh4 cuboctahedra, faces with four equivalent RhIr12 cuboctahedra, and faces with fourteen IrIr8Rh4 cuboctahedra.