ErHo3 is Copper-derived structured and crystallizes in the tetragonal I4/mmm space group. Er(1) is bonded to four equivalent Ho(2) and eight equivalent Ho(1) atoms to form ErHo12 cuboctahedra that share corners with four equivalent Er(1)Ho12 cuboctahedra, corners with eight equivalent Ho(2)Ho8Er4 cuboctahedra, edges with eight equivalent Er(1)Ho12 cuboctahedra, edges with sixteen equivalent Ho(1)Ho8Er4 cuboctahedra, faces with four equivalent Er(1)Ho12 cuboctahedra, faces with six equivalent Ho(2)Ho8Er4 cuboctahedra, and faces with eight equivalent Ho(1)Ho8Er4 cuboctahedra. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to four equivalent Er(1), four equivalent Ho(1), and four equivalent Ho(2) atoms to form HoHo8Er4 cuboctahedra that share corners with twelve equivalent Ho(1)Ho8Er4 cuboctahedra, edges with eight equivalent Er(1)Ho12 cuboctahedra, edges with eight equivalent Ho(1)Ho8Er4 cuboctahedra, edges with eight equivalent Ho(2)Ho8Er4 cuboctahedra, faces with four equivalent Er(1)Ho12 cuboctahedra, faces with four equivalent Ho(2)Ho8Er4 cuboctahedra, and faces with ten equivalent Ho(1)Ho8Er4 cuboctahedra. In the second Ho site, Ho(2) is bonded to four equivalent Er(1) and eight equivalent Ho(1) atoms to form HoHo8Er4 cuboctahedra that share corners with four equivalent Ho(2)Ho8Er4 cuboctahedra, corners with eight equivalent Er(1)Ho12 cuboctahedra, edges with eight equivalent Ho(2)Ho8Er4 cuboctahedra, edges with sixteen equivalent Ho(1)Ho8Er4 cuboctahedra, faces with four equivalent Ho(2)Ho8Er4 cuboctahedra, faces with six equivalent Er(1)Ho12 cuboctahedra, and faces with eight equivalent Ho(1)Ho8Er4 cuboctahedra.
ErHo3 is Copper-derived structured and crystallizes in the tetragonal I4/mmm space group. Er(1) is bonded to four equivalent Ho(2) and eight equivalent Ho(1) atoms to form ErHo12 cuboctahedra that share corners with four equivalent Er(1)Ho12 cuboctahedra, corners with eight equivalent Ho(2)Ho8Er4 cuboctahedra, edges with eight equivalent Er(1)Ho12 cuboctahedra, edges with sixteen equivalent Ho(1)Ho8Er4 cuboctahedra, faces with four equivalent Er(1)Ho12 cuboctahedra, faces with six equivalent Ho(2)Ho8Er4 cuboctahedra, and faces with eight equivalent Ho(1)Ho8Er4 cuboctahedra. All Er(1)-Ho(2) bond lengths are 3.52 Å. All Er(1)-Ho(1) bond lengths are 3.52 Å. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to four equivalent Er(1), four equivalent Ho(1), and four equivalent Ho(2) atoms to form HoHo8Er4 cuboctahedra that share corners with twelve equivalent Ho(1)Ho8Er4 cuboctahedra, edges with eight equivalent Er(1)Ho12 cuboctahedra, edges with eight equivalent Ho(1)Ho8Er4 cuboctahedra, edges with eight equivalent Ho(2)Ho8Er4 cuboctahedra, faces with four equivalent Er(1)Ho12 cuboctahedra, faces with four equivalent Ho(2)Ho8Er4 cuboctahedra, and faces with ten equivalent Ho(1)Ho8Er4 cuboctahedra. All Ho(1)-Ho(1) bond lengths are 3.52 Å. All Ho(1)-Ho(2) bond lengths are 3.52 Å. In the second Ho site, Ho(2) is bonded to four equivalent Er(1) and eight equivalent Ho(1) atoms to form HoHo8Er4 cuboctahedra that share corners with four equivalent Ho(2)Ho8Er4 cuboctahedra, corners with eight equivalent Er(1)Ho12 cuboctahedra, edges with eight equivalent Ho(2)Ho8Er4 cuboctahedra, edges with sixteen equivalent Ho(1)Ho8Er4 cuboctahedra, faces with four equivalent Ho(2)Ho8Er4 cuboctahedra, faces with six equivalent Er(1)Ho12 cuboctahedra, and faces with eight equivalent Ho(1)Ho8Er4 cuboctahedra.