Ho12Al7Si crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 4-coordinate geometry to two equivalent Al(1) and four equivalent Al(3) atoms. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to one Al(1), one Al(2), three equivalent Al(3), and one Si(1) atom. In the third Ho site, Ho(3) is bonded in a 5-coordinate geometry to two equivalent Al(3) and three equivalent Al(1) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to two equivalent Ho(1), three equivalent Ho(3), and four equivalent Ho(2) atoms. In the second Al site, Al(2) is bonded in a body-centered cubic geometry to eight equivalent Ho(2) atoms. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to one Ho(3), two equivalent Ho(1), six equivalent Ho(2), and one Al(3) atom. Si(1) is bonded in a 8-coordinate geometry to eight equivalent Ho(2) atoms.
Ho12Al7Si crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 4-coordinate geometry to two equivalent Al(1) and four equivalent Al(3) atoms. Both Ho(1)-Al(1) bond lengths are 2.96 Å. There are two shorter (3.05 Å) and two longer (3.70 Å) Ho(1)-Al(3) bond lengths. In the second Ho site, Ho(2) is bonded in a 6-coordinate geometry to one Al(1), one Al(2), three equivalent Al(3), and one Si(1) atom. The Ho(2)-Al(1) bond length is 3.02 Å. The Ho(2)-Al(2) bond length is 3.20 Å. There are a spread of Ho(2)-Al(3) bond distances ranging from 3.11-3.31 Å. The Ho(2)-Si(1) bond length is 3.00 Å. In the third Ho site, Ho(3) is bonded in a 5-coordinate geometry to two equivalent Al(3) and three equivalent Al(1) atoms. Both Ho(3)-Al(3) bond lengths are 3.09 Å. There are two shorter (3.40 Å) and one longer (3.48 Å) Ho(3)-Al(1) bond length. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to two equivalent Ho(1), three equivalent Ho(3), and four equivalent Ho(2) atoms. In the second Al site, Al(2) is bonded in a body-centered cubic geometry to eight equivalent Ho(2) atoms. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to one Ho(3), two equivalent Ho(1), six equivalent Ho(2), and one Al(3) atom. The Al(3)-Al(3) bond length is 2.75 Å. Si(1) is bonded in a 8-coordinate geometry to eight equivalent Ho(2) atoms.