Sc3(FeSi3)2 crystallizes in the orthorhombic Cmce space group. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 8-coordinate geometry to one Si(6), two equivalent Si(2), two equivalent Si(3), and three equivalent Si(5) atoms. In the second Sc site, Sc(2) is bonded in a 7-coordinate geometry to two equivalent Fe(2), one Si(1), one Si(6), two equivalent Si(2), and three equivalent Si(4) atoms. In the third Sc site, Sc(3) is bonded in a 12-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), one Si(4), one Si(6), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to two equivalent Sc(3), one Si(1), one Si(5), two equivalent Si(2), and two equivalent Si(3) atoms. In the second Fe site, Fe(2) is bonded to two equivalent Sc(2), two equivalent Sc(3), two equivalent Fe(2), two equivalent Si(1), two equivalent Si(4), and two equivalent Si(6) atoms to form a mixture of distorted face and corner-sharing FeSc4Fe2Si6 cuboctahedra. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Sc(2), two equivalent Sc(3), one Fe(1), two equivalent Fe(2), and one Si(5) atom. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Sc(1), two equivalent Sc(2), two equivalent Sc(3), two equivalent Fe(1), and two equivalent Si(2) atoms. In the third Si site, Si(6) is bonded in a 5-coordinate geometry to one Sc(1), one Sc(2), one Sc(3), and two equivalent Fe(2) atoms. In the fourth Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Sc(1), two equivalent Sc(3), two equivalent Fe(1), and two equivalent Si(3) atoms. In the fifth Si site, Si(4) is bonded in a 6-coordinate geometry to one Sc(3), three equivalent Sc(2), two equivalent Fe(2), and one Si(5) atom. In the sixth Si site, Si(5) is bonded in a 6-coordinate geometry to three equivalent Sc(1), one Fe(1), one Si(1), and one Si(4) atom.
Sc3(FeSi3)2 crystallizes in the orthorhombic Cmce space group. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 8-coordinate geometry to one Si(6), two equivalent Si(2), two equivalent Si(3), and three equivalent Si(5) atoms. The Sc(1)-Si(6) bond length is 2.71 Å. Both Sc(1)-Si(2) bond lengths are 2.80 Å. Both Sc(1)-Si(3) bond lengths are 2.92 Å. All Sc(1)-Si(5) bond lengths are 2.76 Å. In the second Sc site, Sc(2) is bonded in a 7-coordinate geometry to two equivalent Fe(2), one Si(1), one Si(6), two equivalent Si(2), and three equivalent Si(4) atoms. Both Sc(2)-Fe(2) bond lengths are 2.99 Å. The Sc(2)-Si(1) bond length is 2.78 Å. The Sc(2)-Si(6) bond length is 2.69 Å. Both Sc(2)-Si(2) bond lengths are 2.78 Å. There are two shorter (2.86 Å) and one longer (2.89 Å) Sc(2)-Si(4) bond length. In the third Sc site, Sc(3) is bonded in a 12-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), one Si(4), one Si(6), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms. Both Sc(3)-Fe(1) bond lengths are 2.97 Å. Both Sc(3)-Fe(2) bond lengths are 2.94 Å. The Sc(3)-Si(4) bond length is 2.81 Å. The Sc(3)-Si(6) bond length is 2.65 Å. Both Sc(3)-Si(1) bond lengths are 2.80 Å. Both Sc(3)-Si(2) bond lengths are 2.72 Å. Both Sc(3)-Si(3) bond lengths are 2.93 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to two equivalent Sc(3), one Si(1), one Si(5), two equivalent Si(2), and two equivalent Si(3) atoms. The Fe(1)-Si(1) bond length is 2.41 Å. The Fe(1)-Si(5) bond length is 2.45 Å. Both Fe(1)-Si(2) bond lengths are 2.39 Å. Both Fe(1)-Si(3) bond lengths are 2.32 Å. In the second Fe site, Fe(2) is bonded to two equivalent Sc(2), two equivalent Sc(3), two equivalent Fe(2), two equivalent Si(1), two equivalent Si(4), and two equivalent Si(6) atoms to form a mixture of distorted face and corner-sharing FeSc4Fe2Si6 cuboctahedra. Both Fe(2)-Fe(2) bond lengths are 2.54 Å. Both Fe(2)-Si(1) bond lengths are 2.37 Å. Both Fe(2)-Si(4) bond lengths are 2.37 Å. Both Fe(2)-Si(6) bond lengths are 2.39 Å. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Sc(2), two equivalent Sc(3), one Fe(1), two equivalent Fe(2), and one Si(5) atom. The Si(1)-Si(5) bond length is 2.43 Å. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Sc(1), two equivalent Sc(2), two equivalent Sc(3), two equivalent Fe(1), and two equivalent Si(2) atoms. Both Si(2)-Si(2) bond lengths are 2.54 Å. In the third Si site, Si(6) is bonded in a 5-coordinate geometry to one Sc(1), one Sc(2), one Sc(3), and two equivalent Fe(2) atoms. In the fourth Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Sc(1), two equivalent Sc(3), two equivalent Fe(1), and two equivalent Si(3) atoms. There is one shorter (2.52 Å) and one longer (2.55 Å) Si(3)-Si(3) bond length. In the fifth Si site, Si(4) is bonded in a 6-coordinate geometry to one Sc(3), three equivalent Sc(2), two equivalent Fe(2), and one Si(5) atom. The Si(4)-Si(5) bond length is 2.58 Å. In the sixth Si site, Si(5) is bonded in a 6-coordinate geometry to three equivalent Sc(1), one Fe(1), one Si(1), and one Si(4) atom.