HoNiAl crystallizes in the orthorhombic Amm2 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 Ho(2), two equivalent Ni(1), three equivalent Ni(2), one Al(3), two equivalent Al(1), and four equivalent Al(2) atoms. In the second Ho site, Ho(2) is bonded in a 16-coordinate geometry to one Ho(2), three equivalent Ho(1), three equivalent Ni(2), four equivalent Ni(1), one Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Ni(1), two equivalent Ni(2), and two equivalent Al(3) atoms to form distorted NiHo6Al2Ni4 cuboctahedra that share corners with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with six equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with two equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, edges with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, faces with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with two equivalent Al(2)Ho6Al4Ni2 cuboctahedra, faces with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with four equivalent Al(3)Ho6Ni6 cuboctahedra, and faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra. In the second Ni site, Ni(2) is bonded to three equivalent Ho(1), three equivalent Ho(2), two equivalent Ni(1), one Al(1), one Al(3), and two equivalent Al(2) atoms to form distorted NiHo6Al4Ni2 cuboctahedra that share corners with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with two equivalent Al(3)Ho6Ni6 cuboctahedra, corners with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, faces with two equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, faces with three equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with three equivalent Al(3)Ho6Ni6 cuboctahedra, faces with six equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, and faces with six equivalent Al(2)Ho6Al4Ni2 cuboctahedra. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Ho(2), four equivalent Ho(1), two equivalent Ni(2), and four equivalent Al(2) atoms to form distorted AlHo6Al4Ni2 cuboctahedra that share corners with two equivalent Al(3)Ho6Ni6 cuboctahedra, corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with eight equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, edges with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, edges with four equivalent Al(3)Ho6Ni6 cuboctahedra, faces with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, and faces with eight equivalent Al(2)Ho6Al4Ni2 cuboctahedra. In the second Al site, Al(2) is bonded to two equivalent Ho(2), four equivalent Ho(1), two equivalent Ni(2), two equivalent Al(1), and two equivalent Al(2) atoms to form distorted AlHo6Al4Ni2 cuboctahedra that share corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(3)Ho6Ni6 cuboctahedra, corners with six equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, edges with two equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with two equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with two equivalent Al(3)Ho6Ni6 cuboctahedra, faces with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, and faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra. In the third Al site, Al(3) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Ni(2), and four equivalent Ni(1) atoms to form distorted AlHo6Ni6 cuboctahedra that share corners with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(3)Ho6Ni6 cuboctahedra, corners with eight equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with two equivalent Al(3)Ho6Ni6 cuboctahedra, edges with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, and faces with eight equivalent Ni(1)Ho6Al2Ni4 cuboctahedra.
HoNiAl crystallizes in the orthorhombic Amm2 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 Ho(2), two equivalent Ni(1), three equivalent Ni(2), one Al(3), two equivalent Al(1), and four equivalent Al(2) atoms. There is one shorter (3.15 Å) and two longer (3.25 Å) Ho(1)-Ho(2) bond lengths. Both Ho(1)-Ni(1) bond lengths are 2.93 Å. There is one shorter (3.05 Å) and two longer (3.11 Å) Ho(1)-Ni(2) bond lengths. The Ho(1)-Al(3) bond length is 3.09 Å. Both Ho(1)-Al(1) bond lengths are 3.25 Å. There are two shorter (3.18 Å) and two longer (3.22 Å) Ho(1)-Al(2) bond lengths. In the second Ho site, Ho(2) is bonded in a 16-coordinate geometry to one Ho(2), three equivalent Ho(1), three equivalent Ni(2), four equivalent Ni(1), one Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. The Ho(2)-Ho(2) bond length is 3.15 Å. There is one shorter (3.13 Å) and two longer (3.16 Å) Ho(2)-Ni(2) bond lengths. There are two shorter (2.98 Å) and two longer (3.18 Å) Ho(2)-Ni(1) bond lengths. The Ho(2)-Al(1) bond length is 3.13 Å. Both Ho(2)-Al(2) bond lengths are 3.16 Å. Both Ho(2)-Al(3) bond lengths are 3.14 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Ni(1), two equivalent Ni(2), and two equivalent Al(3) atoms to form distorted NiHo6Al2Ni4 cuboctahedra that share corners with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with six equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with two equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, edges with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, faces with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with two equivalent Al(2)Ho6Al4Ni2 cuboctahedra, faces with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with four equivalent Al(3)Ho6Ni6 cuboctahedra, and faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra. There is one shorter (2.64 Å) and one longer (2.76 Å) Ni(1)-Ni(1) bond length. Both Ni(1)-Ni(2) bond lengths are 2.76 Å. There is one shorter (2.53 Å) and one longer (2.77 Å) Ni(1)-Al(3) bond length. In the second Ni site, Ni(2) is bonded to three equivalent Ho(1), three equivalent Ho(2), two equivalent Ni(1), one Al(1), one Al(3), and two equivalent Al(2) atoms to form distorted NiHo6Al4Ni2 cuboctahedra that share corners with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with two equivalent Al(3)Ho6Ni6 cuboctahedra, corners with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, faces with two equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, faces with three equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with three equivalent Al(3)Ho6Ni6 cuboctahedra, faces with six equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, and faces with six equivalent Al(2)Ho6Al4Ni2 cuboctahedra. The Ni(2)-Al(1) bond length is 2.58 Å. The Ni(2)-Al(3) bond length is 2.57 Å. Both Ni(2)-Al(2) bond lengths are 2.57 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Ho(2), four equivalent Ho(1), two equivalent Ni(2), and four equivalent Al(2) atoms to form distorted AlHo6Al4Ni2 cuboctahedra that share corners with two equivalent Al(3)Ho6Ni6 cuboctahedra, corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with eight equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, edges with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, edges with four equivalent Al(3)Ho6Ni6 cuboctahedra, faces with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, and faces with eight equivalent Al(2)Ho6Al4Ni2 cuboctahedra. There are two shorter (2.64 Å) and two longer (2.65 Å) Al(1)-Al(2) bond lengths. In the second Al site, Al(2) is bonded to two equivalent Ho(2), four equivalent Ho(1), two equivalent Ni(2), two equivalent Al(1), and two equivalent Al(2) atoms to form distorted AlHo6Al4Ni2 cuboctahedra that share corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(3)Ho6Ni6 cuboctahedra, corners with six equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, edges with two equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with four equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with two equivalent Ni(1)Ho6Al2Ni4 cuboctahedra, faces with two equivalent Al(3)Ho6Ni6 cuboctahedra, faces with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, and faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra. There is one shorter (2.68 Å) and one longer (2.72 Å) Al(2)-Al(2) bond length. In the third Al site, Al(3) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Ni(2), and four equivalent Ni(1) atoms to form distorted AlHo6Ni6 cuboctahedra that share corners with two equivalent Al(1)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, corners with four equivalent Al(3)Ho6Ni6 cuboctahedra, corners with eight equivalent Al(2)Ho6Al4Ni2 cuboctahedra, edges with two equivalent Al(3)Ho6Ni6 cuboctahedra, edges with four equivalent Al(1)Ho6Al4Ni2 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Ni2 cuboctahedra, faces with six equivalent Ni(2)Ho6Al4Ni2 cuboctahedra, and faces with eight equivalent Ni(1)Ho6Al2Ni4 cuboctahedra.