IrHg3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Ir(1) is bonded to four equivalent Hg(2) and eight equivalent Hg(1) atoms to form IrHg12 cuboctahedra that share corners with four equivalent Ir(1)Hg12 cuboctahedra, corners with eight equivalent Hg(2)Hg8Ir4 cuboctahedra, edges with eight equivalent Ir(1)Hg12 cuboctahedra, edges with sixteen equivalent Hg(1)Hg8Ir4 cuboctahedra, faces with four equivalent Ir(1)Hg12 cuboctahedra, faces with six equivalent Hg(2)Hg8Ir4 cuboctahedra, and faces with eight equivalent Hg(1)Hg8Ir4 cuboctahedra. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to four equivalent Ir(1), four equivalent Hg(1), and four equivalent Hg(2) atoms to form HgHg8Ir4 cuboctahedra that share corners with twelve equivalent Hg(1)Hg8Ir4 cuboctahedra, edges with eight equivalent Ir(1)Hg12 cuboctahedra, edges with eight equivalent Hg(1)Hg8Ir4 cuboctahedra, edges with eight equivalent Hg(2)Hg8Ir4 cuboctahedra, faces with four equivalent Ir(1)Hg12 cuboctahedra, faces with four equivalent Hg(2)Hg8Ir4 cuboctahedra, and faces with ten equivalent Hg(1)Hg8Ir4 cuboctahedra. In the second Hg site, Hg(2) is bonded to four equivalent Ir(1) and eight equivalent Hg(1) atoms to form distorted HgHg8Ir4 cuboctahedra that share corners with four equivalent Hg(2)Hg8Ir4 cuboctahedra, corners with eight equivalent Ir(1)Hg12 cuboctahedra, edges with eight equivalent Hg(2)Hg8Ir4 cuboctahedra, edges with sixteen equivalent Hg(1)Hg8Ir4 cuboctahedra, faces with four equivalent Hg(2)Hg8Ir4 cuboctahedra, faces with six equivalent Ir(1)Hg12 cuboctahedra, and faces with eight equivalent Hg(1)Hg8Ir4 cuboctahedra.
IrHg3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Ir(1) is bonded to four equivalent Hg(2) and eight equivalent Hg(1) atoms to form IrHg12 cuboctahedra that share corners with four equivalent Ir(1)Hg12 cuboctahedra, corners with eight equivalent Hg(2)Hg8Ir4 cuboctahedra, edges with eight equivalent Ir(1)Hg12 cuboctahedra, edges with sixteen equivalent Hg(1)Hg8Ir4 cuboctahedra, faces with four equivalent Ir(1)Hg12 cuboctahedra, faces with six equivalent Hg(2)Hg8Ir4 cuboctahedra, and faces with eight equivalent Hg(1)Hg8Ir4 cuboctahedra. All Ir(1)-Hg(2) bond lengths are 2.94 Å. All Ir(1)-Hg(1) bond lengths are 3.10 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to four equivalent Ir(1), four equivalent Hg(1), and four equivalent Hg(2) atoms to form HgHg8Ir4 cuboctahedra that share corners with twelve equivalent Hg(1)Hg8Ir4 cuboctahedra, edges with eight equivalent Ir(1)Hg12 cuboctahedra, edges with eight equivalent Hg(1)Hg8Ir4 cuboctahedra, edges with eight equivalent Hg(2)Hg8Ir4 cuboctahedra, faces with four equivalent Ir(1)Hg12 cuboctahedra, faces with four equivalent Hg(2)Hg8Ir4 cuboctahedra, and faces with ten equivalent Hg(1)Hg8Ir4 cuboctahedra. All Hg(1)-Hg(1) bond lengths are 2.94 Å. All Hg(1)-Hg(2) bond lengths are 3.10 Å. In the second Hg site, Hg(2) is bonded to four equivalent Ir(1) and eight equivalent Hg(1) atoms to form distorted HgHg8Ir4 cuboctahedra that share corners with four equivalent Hg(2)Hg8Ir4 cuboctahedra, corners with eight equivalent Ir(1)Hg12 cuboctahedra, edges with eight equivalent Hg(2)Hg8Ir4 cuboctahedra, edges with sixteen equivalent Hg(1)Hg8Ir4 cuboctahedra, faces with four equivalent Hg(2)Hg8Ir4 cuboctahedra, faces with six equivalent Ir(1)Hg12 cuboctahedra, and faces with eight equivalent Hg(1)Hg8Ir4 cuboctahedra.