Sm2Fe2O5 is Aluminum carbonitride-like structured and crystallizes in the triclinic P1 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted corner-sharing FeO5 trigonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(3), two equivalent O(2), and two equivalent O(5) atoms to form corner-sharing FeO5 trigonal bipyramids. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to two equivalent Sm(2) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded to two equivalent Sm(1) and two equivalent Fe(2) atoms to form distorted OSm2Fe2 trigonal pyramids that share corners with four equivalent O(4)Sm4Fe2 octahedra and corners with four equivalent O(2)Sm2Fe2 trigonal pyramids. The corner-sharing octahedral tilt angles range from 72-76°. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to two equivalent Sm(2), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded to two equivalent Sm(1), two equivalent Sm(2), and two equivalent Fe(1) atoms to form distorted OSm4Fe2 octahedra that share corners with two equivalent O(4)Sm4Fe2 octahedra, corners with four equivalent O(2)Sm2Fe2 trigonal pyramids, and edges with two equivalent O(4)Sm4Fe2 octahedra. The corner-sharing octahedral tilt angles are 25°. In the fifth O site, O(5) is bonded in a see-saw-like geometry to two equivalent Sm(1) and two equivalent Fe(2) atoms.
Sm2Fe2O5 is Aluminum carbonitride-like structured and crystallizes in the triclinic P1 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There is one shorter (2.27 Å) and one longer (2.30 Å) Sm(1)-O(2) bond length. There is one shorter (2.59 Å) and one longer (2.63 Å) Sm(1)-O(4) bond length. Both Sm(1)-O(5) bond lengths are 2.34 Å. In the second Sm site, Sm(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. There is one shorter (2.38 Å) and one longer (2.42 Å) Sm(2)-O(1) bond length. Both Sm(2)-O(3) bond lengths are 2.25 Å. There is one shorter (2.71 Å) and one longer (2.81 Å) Sm(2)-O(4) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted corner-sharing FeO5 trigonal bipyramids. The Fe(1)-O(3) bond length is 2.36 Å. Both Fe(1)-O(1) bond lengths are 1.97 Å. There is one shorter (2.07 Å) and one longer (2.20 Å) Fe(1)-O(4) bond length. In the second Fe site, Fe(2) is bonded to one O(3), two equivalent O(2), and two equivalent O(5) atoms to form corner-sharing FeO5 trigonal bipyramids. The Fe(2)-O(3) bond length is 2.08 Å. There is one shorter (2.06 Å) and one longer (2.14 Å) Fe(2)-O(2) bond length. There is one shorter (2.05 Å) and one longer (2.19 Å) Fe(2)-O(5) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to two equivalent Sm(2) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded to two equivalent Sm(1) and two equivalent Fe(2) atoms to form distorted OSm2Fe2 trigonal pyramids that share corners with four equivalent O(4)Sm4Fe2 octahedra and corners with four equivalent O(2)Sm2Fe2 trigonal pyramids. The corner-sharing octahedral tilt angles range from 72-76°. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to two equivalent Sm(2), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded to two equivalent Sm(1), two equivalent Sm(2), and two equivalent Fe(1) atoms to form distorted OSm4Fe2 octahedra that share corners with two equivalent O(4)Sm4Fe2 octahedra, corners with four equivalent O(2)Sm2Fe2 trigonal pyramids, and edges with two equivalent O(4)Sm4Fe2 octahedra. The corner-sharing octahedral tilt angles are 25°. In the fifth O site, O(5) is bonded in a see-saw-like geometry to two equivalent Sm(1) and two equivalent Fe(2) atoms.