HoNi3 crystallizes in the trigonal R-3m space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 12-coordinate geometry to three equivalent Ni(2) and nine equivalent Ni(1) atoms. In the second Ho site, Ho(2) is bonded in a distorted hexagonal planar geometry to six equivalent Ni(3) and twelve equivalent Ni(1) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Ho(2), three equivalent Ho(1), one Ni(2), two equivalent Ni(3), and four equivalent Ni(1) atoms to form distorted NiHo5Ni7 cuboctahedra that share corners with two equivalent Ni(2)Ho6Ni6 cuboctahedra, corners with fifteen equivalent Ni(1)Ho5Ni7 cuboctahedra, edges with eight equivalent Ni(1)Ho5Ni7 cuboctahedra, faces with three equivalent Ni(2)Ho6Ni6 cuboctahedra, and faces with eleven equivalent Ni(1)Ho5Ni7 cuboctahedra. In the second Ni site, Ni(2) is bonded to six equivalent Ho(1) and six equivalent Ni(1) atoms to form NiHo6Ni6 cuboctahedra that share corners with twelve equivalent Ni(1)Ho5Ni7 cuboctahedra, edges with six equivalent Ni(2)Ho6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(1)Ho5Ni7 cuboctahedra. In the third Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Ho(2) and six equivalent Ni(1) atoms.
HoNi3 crystallizes in the trigonal R-3m space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 12-coordinate geometry to three equivalent Ni(2) and nine equivalent Ni(1) atoms. All Ho(1)-Ni(2) bond lengths are 2.91 Å. There are six shorter (2.81 Å) and three longer (3.05 Å) Ho(1)-Ni(1) bond lengths. In the second Ho site, Ho(2) is bonded in a distorted hexagonal planar geometry to six equivalent Ni(3) and twelve equivalent Ni(1) atoms. All Ho(2)-Ni(3) bond lengths are 2.83 Å. All Ho(2)-Ni(1) bond lengths are 3.14 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Ho(2), three equivalent Ho(1), one Ni(2), two equivalent Ni(3), and four equivalent Ni(1) atoms to form distorted NiHo5Ni7 cuboctahedra that share corners with two equivalent Ni(2)Ho6Ni6 cuboctahedra, corners with fifteen equivalent Ni(1)Ho5Ni7 cuboctahedra, edges with eight equivalent Ni(1)Ho5Ni7 cuboctahedra, faces with three equivalent Ni(2)Ho6Ni6 cuboctahedra, and faces with eleven equivalent Ni(1)Ho5Ni7 cuboctahedra. The Ni(1)-Ni(2) bond length is 2.49 Å. There is one shorter (2.41 Å) and one longer (2.42 Å) Ni(1)-Ni(3) bond length. There are two shorter (2.44 Å) and two longer (2.46 Å) Ni(1)-Ni(1) bond lengths. In the second Ni site, Ni(2) is bonded to six equivalent Ho(1) and six equivalent Ni(1) atoms to form NiHo6Ni6 cuboctahedra that share corners with twelve equivalent Ni(1)Ho5Ni7 cuboctahedra, edges with six equivalent Ni(2)Ho6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(1)Ho5Ni7 cuboctahedra. In the third Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Ho(2) and six equivalent Ni(1) atoms.