HoNiCu4 crystallizes in the hexagonal P-6m2 space group. Ho(1) is bonded in a distorted hexagonal planar geometry to three equivalent Ni(1), three equivalent Cu(1), and twelve equivalent Cu(2) atoms. Ni(1) is bonded to three equivalent Ho(1), three equivalent Cu(1), and six equivalent Cu(2) atoms to form distorted NiHo3Cu9 cuboctahedra that share corners with nine equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, corners with twelve equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, edges with six equivalent Ni(1)Ho3Cu9 cuboctahedra, faces with two equivalent Ni(1)Ho3Cu9 cuboctahedra, faces with three equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, and faces with eighteen equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Ho(1), three equivalent Ni(1), and six equivalent Cu(2) atoms to form distorted CuHo3Cu6Ni3 cuboctahedra that share corners with nine equivalent Ni(1)Ho3Cu9 cuboctahedra, corners with twelve equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, edges with six equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, faces with two equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, faces with three equivalent Ni(1)Ho3Cu9 cuboctahedra, and faces with eighteen equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra. In the second Cu site, Cu(2) is bonded to four equivalent Ho(1), two equivalent Ni(1), two equivalent Cu(1), and four equivalent Cu(2) atoms to form CuHo4Cu6Ni2 cuboctahedra that share corners with four equivalent Ni(1)Ho3Cu9 cuboctahedra, corners with four equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, corners with sixteen equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, edges with ten equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, faces with six equivalent Ni(1)Ho3Cu9 cuboctahedra, faces with six equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, and faces with ten equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra.
HoNiCu4 crystallizes in the hexagonal P-6m2 space group. Ho(1) is bonded in a distorted hexagonal planar geometry to three equivalent Ni(1), three equivalent Cu(1), and twelve equivalent Cu(2) atoms. All Ho(1)-Ni(1) bond lengths are 2.83 Å. All Ho(1)-Cu(1) bond lengths are 2.83 Å. All Ho(1)-Cu(2) bond lengths are 3.17 Å. Ni(1) is bonded to three equivalent Ho(1), three equivalent Cu(1), and six equivalent Cu(2) atoms to form distorted NiHo3Cu9 cuboctahedra that share corners with nine equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, corners with twelve equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, edges with six equivalent Ni(1)Ho3Cu9 cuboctahedra, faces with two equivalent Ni(1)Ho3Cu9 cuboctahedra, faces with three equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, and faces with eighteen equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra. All Ni(1)-Cu(1) bond lengths are 2.83 Å. All Ni(1)-Cu(2) bond lengths are 2.46 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Ho(1), three equivalent Ni(1), and six equivalent Cu(2) atoms to form distorted CuHo3Cu6Ni3 cuboctahedra that share corners with nine equivalent Ni(1)Ho3Cu9 cuboctahedra, corners with twelve equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, edges with six equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, faces with two equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, faces with three equivalent Ni(1)Ho3Cu9 cuboctahedra, and faces with eighteen equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra. All Cu(1)-Cu(2) bond lengths are 2.47 Å. In the second Cu site, Cu(2) is bonded to four equivalent Ho(1), two equivalent Ni(1), two equivalent Cu(1), and four equivalent Cu(2) atoms to form CuHo4Cu6Ni2 cuboctahedra that share corners with four equivalent Ni(1)Ho3Cu9 cuboctahedra, corners with four equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, corners with sixteen equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, edges with ten equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra, faces with six equivalent Ni(1)Ho3Cu9 cuboctahedra, faces with six equivalent Cu(1)Ho3Cu6Ni3 cuboctahedra, and faces with ten equivalent Cu(2)Ho4Cu6Ni2 cuboctahedra. There are two shorter (2.44 Å) and two longer (2.47 Å) Cu(2)-Cu(2) bond lengths.