HoFeAl crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 16-coordinate geometry to one Ho(1), three equivalent Ho(2), three equivalent Fe(1), four equivalent Fe(2), one Al(3), two equivalent Al(1), and two equivalent Al(2) atoms. In the second Ho site, Ho(2) is bonded in a 12-coordinate geometry to three equivalent Ho(1), two equivalent Fe(2), three equivalent Fe(1), one Al(1), two equivalent Al(3), and four equivalent Al(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent Ho(1), three equivalent Ho(2), two equivalent Fe(2), one Al(1), one Al(3), and two equivalent Al(2) atoms to form distorted FeHo6Al4Fe2 cuboctahedra that share corners with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with two equivalent Al(1)Ho6Fe6 cuboctahedra, corners with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, faces with two equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, faces with three equivalent Al(3)Ho6Al4Fe2 cuboctahedra, faces with three equivalent Al(1)Ho6Fe6 cuboctahedra, faces with six equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, and faces with six equivalent Al(2)Ho6Al4Fe2 cuboctahedra. In the second Fe site, Fe(2) is bonded to two equivalent Ho(2), four equivalent Ho(1), two equivalent Fe(1), two equivalent Fe(2), and two equivalent Al(1) atoms to form FeHo6Al2Fe4 cuboctahedra that share corners with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with six equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with two equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, edges with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with two equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, faces with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with four equivalent Al(1)Ho6Fe6 cuboctahedra, and faces with six equivalent Fe(1)Ho6Al4Fe2 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 Fe(1), and four equivalent Fe(2) atoms to form AlHo6Fe6 cuboctahedra that share corners with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(1)Ho6Fe6 cuboctahedra, corners with eight equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with two equivalent Al(1)Ho6Fe6 cuboctahedra, edges with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, and faces with eight equivalent Fe(2)Ho6Al2Fe4 cuboctahedra. In the second Al site, Al(2) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Fe(1), two equivalent Al(2), and two equivalent Al(3) atoms to form AlHo6Al4Fe2 cuboctahedra that share corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(1)Ho6Fe6 cuboctahedra, corners with six equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, edges with two equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with two equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with two equivalent Al(1)Ho6Fe6 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, and faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra. In the third Al site, Al(3) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Fe(1), and four equivalent Al(2) atoms to form AlHo6Al4Fe2 cuboctahedra that share corners with two equivalent Al(1)Ho6Fe6 cuboctahedra, corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with eight equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, edges with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, edges with four equivalent Al(1)Ho6Fe6 cuboctahedra, faces with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, and faces with eight equivalent Al(2)Ho6Al4Fe2 cuboctahedra.
HoFeAl crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 16-coordinate geometry to one Ho(1), three equivalent Ho(2), three equivalent Fe(1), four equivalent Fe(2), one Al(3), two equivalent Al(1), and two equivalent Al(2) atoms. The Ho(1)-Ho(1) bond length is 3.18 Å. There is one shorter (3.25 Å) and two longer (3.28 Å) Ho(1)-Ho(2) bond lengths. There is one shorter (3.09 Å) and two longer (3.18 Å) Ho(1)-Fe(1) bond lengths. There are two shorter (3.11 Å) and two longer (3.16 Å) Ho(1)-Fe(2) bond lengths. The Ho(1)-Al(3) bond length is 3.13 Å. Both Ho(1)-Al(1) bond lengths are 3.13 Å. Both Ho(1)-Al(2) bond lengths are 3.13 Å. In the second Ho site, Ho(2) is bonded in a 12-coordinate geometry to three equivalent Ho(1), two equivalent Fe(2), three equivalent Fe(1), one Al(1), two equivalent Al(3), and four equivalent Al(2) atoms. Both Ho(2)-Fe(2) bond lengths are 3.02 Å. There are two shorter (3.11 Å) and one longer (3.27 Å) Ho(2)-Fe(1) bond length. The Ho(2)-Al(1) bond length is 3.05 Å. Both Ho(2)-Al(3) bond lengths are 3.19 Å. There are two shorter (3.17 Å) and two longer (3.22 Å) Ho(2)-Al(2) bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent Ho(1), three equivalent Ho(2), two equivalent Fe(2), one Al(1), one Al(3), and two equivalent Al(2) atoms to form distorted FeHo6Al4Fe2 cuboctahedra that share corners with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with two equivalent Al(1)Ho6Fe6 cuboctahedra, corners with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, faces with two equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, faces with three equivalent Al(3)Ho6Al4Fe2 cuboctahedra, faces with three equivalent Al(1)Ho6Fe6 cuboctahedra, faces with six equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, and faces with six equivalent Al(2)Ho6Al4Fe2 cuboctahedra. Both Fe(1)-Fe(2) bond lengths are 2.52 Å. The Fe(1)-Al(1) bond length is 2.59 Å. The Fe(1)-Al(3) bond length is 2.69 Å. Both Fe(1)-Al(2) bond lengths are 2.74 Å. In the second Fe site, Fe(2) is bonded to two equivalent Ho(2), four equivalent Ho(1), two equivalent Fe(1), two equivalent Fe(2), and two equivalent Al(1) atoms to form FeHo6Al2Fe4 cuboctahedra that share corners with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with six equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with two equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, edges with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with two equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, faces with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with four equivalent Al(1)Ho6Fe6 cuboctahedra, and faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra. There is one shorter (2.66 Å) and one longer (2.73 Å) Fe(2)-Fe(2) bond length. There is one shorter (2.64 Å) and one longer (2.77 Å) Fe(2)-Al(1) bond length. 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 Fe(1), and four equivalent Fe(2) atoms to form AlHo6Fe6 cuboctahedra that share corners with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(1)Ho6Fe6 cuboctahedra, corners with eight equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with two equivalent Al(1)Ho6Fe6 cuboctahedra, edges with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, and faces with eight equivalent Fe(2)Ho6Al2Fe4 cuboctahedra. In the second Al site, Al(2) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Fe(1), two equivalent Al(2), and two equivalent Al(3) atoms to form AlHo6Al4Fe2 cuboctahedra that share corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(1)Ho6Fe6 cuboctahedra, corners with six equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, edges with two equivalent Al(2)Ho6Al4Fe2 cuboctahedra, edges with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with two equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with two equivalent Al(1)Ho6Fe6 cuboctahedra, faces with four equivalent Al(2)Ho6Al4Fe2 cuboctahedra, faces with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, and faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra. There is one shorter (2.63 Å) and one longer (2.76 Å) Al(2)-Al(2) bond length. There is one shorter (2.65 Å) and one longer (2.76 Å) Al(2)-Al(3) bond length. In the third Al site, Al(3) is bonded to two equivalent Ho(1), four equivalent Ho(2), two equivalent Fe(1), and four equivalent Al(2) atoms to form AlHo6Al4Fe2 cuboctahedra that share corners with two equivalent Al(1)Ho6Fe6 cuboctahedra, corners with four equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, corners with four equivalent Al(3)Ho6Al4Fe2 cuboctahedra, corners with eight equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, edges with two equivalent Al(3)Ho6Al4Fe2 cuboctahedra, edges with four equivalent Al(1)Ho6Fe6 cuboctahedra, faces with four equivalent Fe(2)Ho6Al2Fe4 cuboctahedra, faces with six equivalent Fe(1)Ho6Al4Fe2 cuboctahedra, and faces with eight equivalent Al(2)Ho6Al4Fe2 cuboctahedra.