Sm2Ni2O5 crystallizes in the orthorhombic Ima2 space group. Sm(1) is bonded in a 8-coordinate geometry to one O(3), three equivalent O(2), and four equivalent O(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra and corners with two equivalent Ni(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 20°. In the second Ni site, Ni(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form NiO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with two equivalent Ni(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Sm(1) and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to three equivalent Sm(1), one Ni(1), and one Ni(2) atom. In the third O site, O(3) is bonded to two equivalent Sm(1) and two equivalent Ni(2) atoms to form corner-sharing OSm2Ni2 tetrahedra.
Sm2Ni2O5 crystallizes in the orthorhombic Ima2 space group. Sm(1) is bonded in a 8-coordinate geometry to one O(3), three equivalent O(2), and four equivalent O(1) atoms. The Sm(1)-O(3) bond length is 2.32 Å. There are a spread of Sm(1)-O(2) bond distances ranging from 2.32-3.00 Å. There are a spread of Sm(1)-O(1) bond distances ranging from 2.41-2.76 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra and corners with two equivalent Ni(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 20°. Both Ni(1)-O(2) bond lengths are 2.17 Å. There are two shorter (1.98 Å) and two longer (1.99 Å) Ni(1)-O(1) bond lengths. In the second Ni site, Ni(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form NiO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with two equivalent Ni(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. Both Ni(2)-O(2) bond lengths are 1.94 Å. There is one shorter (2.03 Å) and one longer (2.06 Å) Ni(2)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to four equivalent Sm(1) and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to three equivalent Sm(1), one Ni(1), and one Ni(2) atom. In the third O site, O(3) is bonded to two equivalent Sm(1) and two equivalent Ni(2) atoms to form corner-sharing OSm2Ni2 tetrahedra.