BaFe2Al9 crystallizes in the hexagonal P6/mmm space group. Ba(1) is bonded to twelve equivalent Al(2) atoms to form face-sharing BaAl12 cuboctahedra. Fe(1) is bonded in a 9-coordinate geometry to three equivalent Al(1) and six equivalent Al(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a linear geometry to two equivalent Fe(1) and eight equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), four equivalent Al(1), and four equivalent Al(2) atoms.
BaFe2Al9 crystallizes in the hexagonal P6/mmm space group. Ba(1) is bonded to twelve equivalent Al(2) atoms to form face-sharing BaAl12 cuboctahedra. All Ba(1)-Al(2) bond lengths are 3.59 Å. Fe(1) is bonded in a 9-coordinate geometry to three equivalent Al(1) and six equivalent Al(2) atoms. All Fe(1)-Al(1) bond lengths are 2.29 Å. All Fe(1)-Al(2) bond lengths are 2.53 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a linear geometry to two equivalent Fe(1) and eight equivalent Al(2) atoms. All Al(1)-Al(2) bond lengths are 2.83 Å. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), four equivalent Al(1), and four equivalent Al(2) atoms. There are two shorter (2.74 Å) and two longer (3.00 Å) Al(2)-Al(2) bond lengths.