Sm6Fe11Al3 crystallizes in the tetragonal I4cm space group. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to one Fe(1), three equivalent Fe(5), and two equivalent Al(1) atoms. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to one Fe(2), two equivalent Al(1), and three equivalent Al(2) atoms. In the third Sm site, Sm(3) is bonded in a 13-coordinate geometry to four equivalent Fe(2), four equivalent Fe(3), one Al(1), and four equivalent Al(2) atoms. In the fourth Sm site, Sm(4) is bonded in a 13-coordinate geometry to four equivalent Fe(1), four equivalent Fe(3), four equivalent Fe(5), and one Al(1) atom. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to one Sm(1), two equivalent Sm(4), one Fe(2), one Fe(4), three equivalent Fe(5), and four equivalent Fe(3) atoms. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to one Sm(2), two equivalent Sm(3), one Fe(1), one Fe(4), four equivalent Fe(3), and three equivalent Al(2) atoms. In the third Fe site, Fe(3) is bonded to one Sm(3), one Sm(4), one Fe(4), one Fe(5), two equivalent Fe(1), two equivalent Fe(2), three equivalent Fe(3), and one Al(2) atom to form FeSm2AlFe9 cuboctahedra that share  a cornercorner with one Fe(4)Al2Fe10 cuboctahedra, corners with two equivalent Fe(5)Sm5Fe7 cuboctahedra, corners with three equivalent Fe(3)Sm2AlFe9 cuboctahedra, faces with two equivalent Fe(4)Al2Fe10 cuboctahedra, faces with four equivalent Fe(5)Sm5Fe7 cuboctahedra, and faces with seven equivalent Fe(3)Sm2AlFe9 cuboctahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), four equivalent Fe(3), and two equivalent Al(2) atoms to form FeAl2Fe10 cuboctahedra that share corners with two equivalent Fe(5)Sm5Fe7 cuboctahedra, corners with four equivalent Fe(3)Sm2AlFe9 cuboctahedra, faces with two equivalent Fe(5)Sm5Fe7 cuboctahedra, and faces with eight equivalent Fe(3)Sm2AlFe9 cuboctahedra. In the fifth Fe site, Fe(5) is bonded to two equivalent Sm(4), three equivalent Sm(1), one Fe(4), one Fe(5), two equivalent Fe(3), and three equivalent Fe(1) atoms to form distorted FeSm5Fe7 cuboctahedra that share  a cornercorner with one Fe(4)Al2Fe10 cuboctahedra, corners with two equivalent Fe(5)Sm5Fe7 cuboctahedra, corners with four equivalent Fe(3)Sm2AlFe9 cuboctahedra,  a faceface with one Fe(4)Al2Fe10 cuboctahedra, faces with five equivalent Fe(5)Sm5Fe7 cuboctahedra, and faces with eight equivalent Fe(3)Sm2AlFe9 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted q6 geometry to one Sm(3), one Sm(4), four equivalent Sm(1), and four equivalent Sm(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two equivalent Sm(3), three equivalent Sm(2), one Fe(4), two equivalent Fe(3), three equivalent Fe(2), and one Al(2) atom.
Sm6Fe11Al3 crystallizes in the tetragonal I4cm space group. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to one Fe(1), three equivalent Fe(5), and two equivalent Al(1) atoms. The Sm(1)-Fe(1) bond length is 2.94 Å. There are two shorter (3.12 Å) and one longer (3.31 Å) Sm(1)-Fe(5) bond length. Both Sm(1)-Al(1) bond lengths are 3.37 Å. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to one Fe(2), two equivalent Al(1), and three equivalent Al(2) atoms. The Sm(2)-Fe(2) bond length is 3.25 Å. Both Sm(2)-Al(1) bond lengths are 3.29 Å. There are two shorter (3.27 Å) and one longer (3.37 Å) Sm(2)-Al(2) bond length. In the third Sm site, Sm(3) is bonded in a 13-coordinate geometry to four equivalent Fe(2), four equivalent Fe(3), one Al(1), and four equivalent Al(2) atoms. All Sm(3)-Fe(2) bond lengths are 3.23 Å. All Sm(3)-Fe(3) bond lengths are 3.10 Å. The Sm(3)-Al(1) bond length is 3.31 Å. All Sm(3)-Al(2) bond lengths are 3.24 Å. In the fourth Sm site, Sm(4) is bonded in a 13-coordinate geometry to four equivalent Fe(1), four equivalent Fe(3), four equivalent Fe(5), and one Al(1) atom. All Sm(4)-Fe(1) bond lengths are 3.18 Å. All Sm(4)-Fe(3) bond lengths are 3.05 Å. All Sm(4)-Fe(5) bond lengths are 3.27 Å. The Sm(4)-Al(1) bond length is 3.32 Å. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to one Sm(1), two equivalent Sm(4), one Fe(2), one Fe(4), three equivalent Fe(5), and four equivalent Fe(3) atoms. The Fe(1)-Fe(2) bond length is 2.70 Å. The Fe(1)-Fe(4) bond length is 2.47 Å. There is one shorter (2.51 Å) and two longer (2.55 Å) Fe(1)-Fe(5) bond lengths. There are two shorter (2.50 Å) and two longer (2.59 Å) Fe(1)-Fe(3) bond lengths. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to one Sm(2), two equivalent Sm(3), one Fe(1), one Fe(4), four equivalent Fe(3), and three equivalent Al(2) atoms. The Fe(2)-Fe(4) bond length is 2.40 Å. There are two shorter (2.47 Å) and two longer (2.56 Å) Fe(2)-Fe(3) bond lengths. There is one shorter (2.52 Å) and two longer (2.61 Å) Fe(2)-Al(2) bond lengths. In the third Fe site, Fe(3) is bonded to one Sm(3), one Sm(4), one Fe(4), one Fe(5), two equivalent Fe(1), two equivalent Fe(2), three equivalent Fe(3), and one Al(2) atom to form FeSm2AlFe9 cuboctahedra that share  a cornercorner with one Fe(4)Al2Fe10 cuboctahedra, corners with two equivalent Fe(5)Sm5Fe7 cuboctahedra, corners with three equivalent Fe(3)Sm2AlFe9 cuboctahedra, faces with two equivalent Fe(4)Al2Fe10 cuboctahedra, faces with four equivalent Fe(5)Sm5Fe7 cuboctahedra, and faces with seven equivalent Fe(3)Sm2AlFe9 cuboctahedra. The Fe(3)-Fe(4) bond length is 2.43 Å. The Fe(3)-Fe(5) bond length is 2.64 Å. There are two shorter (2.50 Å) and one longer (2.57 Å) Fe(3)-Fe(3) bond length. The Fe(3)-Al(2) bond length is 2.70 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), four equivalent Fe(3), and two equivalent Al(2) atoms to form FeAl2Fe10 cuboctahedra that share corners with two equivalent Fe(5)Sm5Fe7 cuboctahedra, corners with four equivalent Fe(3)Sm2AlFe9 cuboctahedra, faces with two equivalent Fe(5)Sm5Fe7 cuboctahedra, and faces with eight equivalent Fe(3)Sm2AlFe9 cuboctahedra. Both Fe(4)-Fe(5) bond lengths are 2.57 Å. Both Fe(4)-Al(2) bond lengths are 2.63 Å. In the fifth Fe site, Fe(5) is bonded to two equivalent Sm(4), three equivalent Sm(1), one Fe(4), one Fe(5), two equivalent Fe(3), and three equivalent Fe(1) atoms to form distorted FeSm5Fe7 cuboctahedra that share  a cornercorner with one Fe(4)Al2Fe10 cuboctahedra, corners with two equivalent Fe(5)Sm5Fe7 cuboctahedra, corners with four equivalent Fe(3)Sm2AlFe9 cuboctahedra,  a faceface with one Fe(4)Al2Fe10 cuboctahedra, faces with five equivalent Fe(5)Sm5Fe7 cuboctahedra, and faces with eight equivalent Fe(3)Sm2AlFe9 cuboctahedra. The Fe(5)-Fe(5) bond length is 2.63 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted q6 geometry to one Sm(3), one Sm(4), four equivalent Sm(1), and four equivalent Sm(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two equivalent Sm(3), three equivalent Sm(2), one Fe(4), two equivalent Fe(3), three equivalent Fe(2), and one Al(2) atom. The Al(2)-Al(2) bond length is 2.73 Å.