Sm12Al7Si crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to one Al(2), one Al(3), three equivalent Al(1), and one Si(1) atom. In the second Sm site, Sm(2) is bonded in a 5-coordinate geometry to two equivalent Al(1) and three equivalent Al(3) atoms. In the third Sm site, Sm(3) is bonded in a 4-coordinate geometry to two equivalent Al(3) and four equivalent Al(1) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to one Sm(2), two equivalent Sm(3), six equivalent Sm(1), and one Al(1) atom. In the second Al site, Al(2) is bonded in a body-centered cubic geometry to eight equivalent Sm(1) atoms. In the third Al site, Al(3) is bonded in a 9-coordinate geometry to two equivalent Sm(3), three equivalent Sm(2), and four equivalent Sm(1) atoms. Si(1) is bonded in a 8-coordinate geometry to eight equivalent Sm(1) atoms.
Sm12Al7Si crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to one Al(2), one Al(3), three equivalent Al(1), and one Si(1) atom. The Sm(1)-Al(2) bond length is 3.27 Å. The Sm(1)-Al(3) bond length is 3.12 Å. There are a spread of Sm(1)-Al(1) bond distances ranging from 3.18-3.44 Å. The Sm(1)-Si(1) bond length is 3.05 Å. In the second Sm site, Sm(2) is bonded in a 5-coordinate geometry to two equivalent Al(1) and three equivalent Al(3) atoms. Both Sm(2)-Al(1) bond lengths are 3.22 Å. There are two shorter (3.46 Å) and one longer (3.58 Å) Sm(2)-Al(3) bond length. In the third Sm site, Sm(3) is bonded in a 4-coordinate geometry to two equivalent Al(3) and four equivalent Al(1) atoms. Both Sm(3)-Al(3) bond lengths are 3.07 Å. There are two shorter (3.13 Å) and two longer (3.77 Å) Sm(3)-Al(1) bond lengths. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to one Sm(2), two equivalent Sm(3), six equivalent Sm(1), and one Al(1) atom. The Al(1)-Al(1) bond length is 2.79 Å. In the second Al site, Al(2) is bonded in a body-centered cubic geometry to eight equivalent Sm(1) atoms. In the third Al site, Al(3) is bonded in a 9-coordinate geometry to two equivalent Sm(3), three equivalent Sm(2), and four equivalent Sm(1) atoms. Si(1) is bonded in a 8-coordinate geometry to eight equivalent Sm(1) atoms.