Al3FeSi2 crystallizes in the orthorhombic Pbcn space group. Fe(1) is bonded in a 10-coordinate geometry to two equivalent Al(1), four equivalent Al(2), and four equivalent Si(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to two equivalent Fe(1), four equivalent Al(2), and four equivalent Si(1) atoms. In the second Al site, Al(2) is bonded in a 9-coordinate geometry to two equivalent Fe(1), one Al(2), two equivalent Al(1), and four equivalent Si(1) atoms. Si(1) is bonded in a 9-coordinate geometry to two equivalent Fe(1), two equivalent Al(1), four equivalent Al(2), and one Si(1) atom.
Al3FeSi2 crystallizes in the orthorhombic Pbcn space group. Fe(1) is bonded in a 10-coordinate geometry to two equivalent Al(1), four equivalent Al(2), and four equivalent Si(1) atoms. Both Fe(1)-Al(1) bond lengths are 2.37 Å. There are two shorter (2.56 Å) and two longer (2.59 Å) Fe(1)-Al(2) bond lengths. There are two shorter (2.44 Å) and two longer (2.46 Å) Fe(1)-Si(1) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to two equivalent Fe(1), four equivalent Al(2), and four equivalent Si(1) atoms. There are two shorter (2.66 Å) and two longer (2.71 Å) Al(1)-Al(2) bond lengths. There are two shorter (2.67 Å) and two longer (2.72 Å) Al(1)-Si(1) bond lengths. In the second Al site, Al(2) is bonded in a 9-coordinate geometry to two equivalent Fe(1), one Al(2), two equivalent Al(1), and four equivalent Si(1) atoms. The Al(2)-Al(2) bond length is 2.75 Å. There are a spread of Al(2)-Si(1) bond distances ranging from 2.60-2.77 Å. Si(1) is bonded in a 9-coordinate geometry to two equivalent Fe(1), two equivalent Al(1), four equivalent Al(2), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.68 Å.