EuAl3Si crystallizes in the tetragonal I4mm space group. Eu(1) is bonded in a 16-coordinate geometry to four equivalent Al(2), eight equivalent Al(1), and four equivalent Si(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 2-coordinate geometry to four equivalent Eu(1), two equivalent Al(2), and two equivalent Si(1) atoms. In the second Al site, Al(2) is bonded in a distorted single-bond geometry to four equivalent Eu(1), four equivalent Al(1), and one Si(1) atom. Si(1) is bonded in a 9-coordinate geometry to four equivalent Eu(1), one Al(2), and four equivalent Al(1) atoms.
EuAl3Si crystallizes in the tetragonal I4mm space group. Eu(1) is bonded in a 16-coordinate geometry to four equivalent Al(2), eight equivalent Al(1), and four equivalent Si(1) atoms. All Eu(1)-Al(2) bond lengths are 3.32 Å. There are four shorter (3.45 Å) and four longer (3.50 Å) Eu(1)-Al(1) bond lengths. All Eu(1)-Si(1) bond lengths are 3.32 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 2-coordinate geometry to four equivalent Eu(1), two equivalent Al(2), and two equivalent Si(1) atoms. Both Al(1)-Al(2) bond lengths are 2.63 Å. Both Al(1)-Si(1) bond lengths are 2.60 Å. In the second Al site, Al(2) is bonded in a distorted single-bond geometry to four equivalent Eu(1), four equivalent Al(1), and one Si(1) atom. The Al(2)-Si(1) bond length is 2.52 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent Eu(1), one Al(2), and four equivalent Al(1) atoms.