Sm2Mn2O5 is Aluminum carbonitride-like structured and crystallizes in the orthorhombic Ima2 space group. Sm(1) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 29°. In the second Mn site, Mn(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form MnO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sm(1) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded to two equivalent Sm(1), one Mn(1), and one Mn(2) atom to form distorted corner-sharing OSm2Mn2 trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Sm(1) and two equivalent Mn(2) atoms to form corner-sharing OSm2Mn2 tetrahedra.
Sm2Mn2O5 is Aluminum carbonitride-like structured and crystallizes in the orthorhombic Ima2 space group. Sm(1) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. The Sm(1)-O(3) bond length is 2.32 Å. There is one shorter (2.40 Å) and one longer (2.47 Å) Sm(1)-O(1) bond length. There is one shorter (2.29 Å) and one longer (2.34 Å) Sm(1)-O(2) bond length. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 29°. Both Mn(1)-O(2) bond lengths are 2.34 Å. There are two shorter (2.09 Å) and two longer (2.12 Å) Mn(1)-O(1) bond lengths. In the second Mn site, Mn(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form MnO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. Both Mn(2)-O(2) bond lengths are 2.03 Å. There is one shorter (2.14 Å) and one longer (2.16 Å) Mn(2)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sm(1) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded to two equivalent Sm(1), one Mn(1), and one Mn(2) atom to form distorted corner-sharing OSm2Mn2 trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Sm(1) and two equivalent Mn(2) atoms to form corner-sharing OSm2Mn2 tetrahedra.