Na2Fe2O5 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded in a 8-coordinate geometry to one O(2), three equivalent O(1), and four equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 10°. In the second Fe site, Fe(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form FeO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to three equivalent Na(1), one Fe(1), and one Fe(2) atom. In the second O site, O(2) is bonded to two equivalent Na(1) and two equivalent Fe(2) atoms to form distorted ONa2Fe2 tetrahedra that share corners with eight equivalent O(3)Na4Fe2 octahedra and corners with two equivalent O(2)Na2Fe2 tetrahedra. The corner-sharing octahedral tilt angles range from 18-83°. In the third O site, O(3) is bonded to four equivalent Na(1) and two equivalent Fe(1) atoms to form distorted ONa4Fe2 octahedra that share corners with two equivalent O(3)Na4Fe2 octahedra, corners with four equivalent O(2)Na2Fe2 tetrahedra, edges with two equivalent O(3)Na4Fe2 octahedra, and faces with four equivalent O(3)Na4Fe2 octahedra. The corner-sharing octahedra are not tilted.
Na2Fe2O5 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded in a 8-coordinate geometry to one O(2), three equivalent O(1), and four equivalent O(3) atoms. The Na(1)-O(2) bond length is 2.34 Å. There are a spread of Na(1)-O(1) bond distances ranging from 2.38-2.92 Å. There are a spread of Na(1)-O(3) bond distances ranging from 2.46-2.62 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 10°. Both Fe(1)-O(1) bond lengths are 2.04 Å. There are two shorter (1.93 Å) and two longer (1.96 Å) Fe(1)-O(3) bond lengths. In the second Fe site, Fe(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form FeO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. Both Fe(2)-O(1) bond lengths are 1.80 Å. Both Fe(2)-O(2) bond lengths are 1.87 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to three equivalent Na(1), one Fe(1), and one Fe(2) atom. In the second O site, O(2) is bonded to two equivalent Na(1) and two equivalent Fe(2) atoms to form distorted ONa2Fe2 tetrahedra that share corners with eight equivalent O(3)Na4Fe2 octahedra and corners with two equivalent O(2)Na2Fe2 tetrahedra. The corner-sharing octahedral tilt angles range from 18-83°. In the third O site, O(3) is bonded to four equivalent Na(1) and two equivalent Fe(1) atoms to form distorted ONa4Fe2 octahedra that share corners with two equivalent O(3)Na4Fe2 octahedra, corners with four equivalent O(2)Na2Fe2 tetrahedra, edges with two equivalent O(3)Na4Fe2 octahedra, and faces with four equivalent O(3)Na4Fe2 octahedra. The corner-sharing octahedra are not tilted.