Ho2FeGa8 crystallizes in the tetragonal P4/mmm space group. Ho(1) is bonded to four equivalent Ga(1), four equivalent Ga(2), and four equivalent Ga(3) atoms to form HoGa12 cuboctahedra that share corners with eight equivalent Ho(1)Ga12 cuboctahedra, edges with four equivalent Ga(2)Ho4Ga8 cuboctahedra, faces with four equivalent Ga(2)Ho4Ga8 cuboctahedra, and faces with five equivalent Ho(1)Ga12 cuboctahedra. Fe(1) is bonded in a body-centered cubic geometry to eight equivalent Ga(3) atoms. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a distorted square co-planar geometry to four equivalent Ho(1) and four equivalent Ga(2) atoms. In the second Ga site, Ga(2) is bonded to four equivalent Ho(1), four equivalent Ga(1), and four equivalent Ga(3) atoms to form distorted GaHo4Ga8 cuboctahedra that share corners with eight equivalent Ga(2)Ho4Ga8 cuboctahedra, edges with four equivalent Ho(1)Ga12 cuboctahedra, faces with four equivalent Ho(1)Ga12 cuboctahedra, and faces with five equivalent Ga(2)Ho4Ga8 cuboctahedra. In the third Ga site, Ga(3) is bonded in a 11-coordinate geometry to two equivalent Ho(1), two equivalent Fe(1), two equivalent Ga(2), and five equivalent Ga(3) atoms.
Ho2FeGa8 crystallizes in the tetragonal P4/mmm space group. Ho(1) is bonded to four equivalent Ga(1), four equivalent Ga(2), and four equivalent Ga(3) atoms to form HoGa12 cuboctahedra that share corners with eight equivalent Ho(1)Ga12 cuboctahedra, edges with four equivalent Ga(2)Ho4Ga8 cuboctahedra, faces with four equivalent Ga(2)Ho4Ga8 cuboctahedra, and faces with five equivalent Ho(1)Ga12 cuboctahedra. All Ho(1)-Ga(1) bond lengths are 3.03 Å. All Ho(1)-Ga(2) bond lengths are 3.00 Å. All Ho(1)-Ga(3) bond lengths are 2.99 Å. Fe(1) is bonded in a body-centered cubic geometry to eight equivalent Ga(3) atoms. All Fe(1)-Ga(3) bond lengths are 2.47 Å. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a distorted square co-planar geometry to four equivalent Ho(1) and four equivalent Ga(2) atoms. All Ga(1)-Ga(2) bond lengths are 3.07 Å. In the second Ga site, Ga(2) is bonded to four equivalent Ho(1), four equivalent Ga(1), and four equivalent Ga(3) atoms to form distorted GaHo4Ga8 cuboctahedra that share corners with eight equivalent Ga(2)Ho4Ga8 cuboctahedra, edges with four equivalent Ho(1)Ga12 cuboctahedra, faces with four equivalent Ho(1)Ga12 cuboctahedra, and faces with five equivalent Ga(2)Ho4Ga8 cuboctahedra. All Ga(2)-Ga(3) bond lengths are 2.95 Å. In the third Ga site, Ga(3) is bonded in a 11-coordinate geometry to two equivalent Ho(1), two equivalent Fe(1), two equivalent Ga(2), and five equivalent Ga(3) atoms. There is one shorter (2.54 Å) and four longer (3.00 Å) Ga(3)-Ga(3) bond lengths.