Sc3Fe2Si3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 9-coordinate geometry to four equivalent Fe(1), two equivalent Si(2), and three equivalent Si(1) atoms. In the second Sc site, Sc(2) is bonded in a 10-coordinate geometry to four equivalent Fe(1), two equivalent Si(1), and five equivalent Si(2) atoms. Fe(1) is bonded in a 10-coordinate geometry to two equivalent Sc(1), four equivalent Sc(2), one Si(1), and three equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent Sc(1), four equivalent Sc(2), and two equivalent Fe(1) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to one Sc(1), five equivalent Sc(2), three equivalent Fe(1), and one Si(2) atom.
Sc3Fe2Si3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 9-coordinate geometry to four equivalent Fe(1), two equivalent Si(2), and three equivalent Si(1) atoms. All Sc(1)-Fe(1) bond lengths are 3.02 Å. Both Sc(1)-Si(2) bond lengths are 2.70 Å. There are two shorter (2.72 Å) and one longer (3.07 Å) Sc(1)-Si(1) bond length. In the second Sc site, Sc(2) is bonded in a 10-coordinate geometry to four equivalent Fe(1), two equivalent Si(1), and five equivalent Si(2) atoms. There are a spread of Sc(2)-Fe(1) bond distances ranging from 2.81-2.95 Å. Both Sc(2)-Si(1) bond lengths are 2.80 Å. There are a spread of Sc(2)-Si(2) bond distances ranging from 2.80-3.10 Å. Fe(1) is bonded in a 10-coordinate geometry to two equivalent Sc(1), four equivalent Sc(2), one Si(1), and three equivalent Si(2) atoms. The Fe(1)-Si(1) bond length is 2.43 Å. There are two shorter (2.25 Å) and one longer (2.28 Å) Fe(1)-Si(2) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent Sc(1), four equivalent Sc(2), and two equivalent Fe(1) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to one Sc(1), five equivalent Sc(2), three equivalent Fe(1), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.55 Å.