Ba2Fe2O5 crystallizes in the orthorhombic Ima2 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) 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 4°. In the second Fe site, Fe(2) is bonded to two equivalent O(2) and two equivalent O(3) 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 26°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Fe(1) atoms to form distorted OBa4Fe2 octahedra that share corners with two equivalent O(1)Ba4Fe2 octahedra, corners with four equivalent O(3)Ba2Fe2 tetrahedra, edges with two equivalent O(1)Ba4Fe2 octahedra, and faces with four equivalent O(1)Ba4Fe2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded to two equivalent Ba(1) and two equivalent Fe(2) atoms to form distorted OBa2Fe2 tetrahedra that share corners with eight equivalent O(1)Ba4Fe2 octahedra and corners with two equivalent O(3)Ba2Fe2 tetrahedra. The corner-sharing octahedral tilt angles range from 16-81°.
Ba2Fe2O5 crystallizes in the orthorhombic Ima2 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. The Ba(1)-O(3) bond length is 2.63 Å. There are a spread of Ba(1)-O(1) bond distances ranging from 2.75-2.79 Å. There are a spread of Ba(1)-O(2) bond distances ranging from 2.72-3.27 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) 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 4°. Both Fe(1)-O(2) bond lengths are 2.31 Å. There are two shorter (2.07 Å) and two longer (2.08 Å) Fe(1)-O(1) bond lengths. In the second Fe site, Fe(2) is bonded to two equivalent O(2) and two equivalent O(3) 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 26°. Both Fe(2)-O(2) bond lengths are 1.92 Å. Both Fe(2)-O(3) bond lengths are 1.92 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1) and two equivalent Fe(1) atoms to form distorted OBa4Fe2 octahedra that share corners with two equivalent O(1)Ba4Fe2 octahedra, corners with four equivalent O(3)Ba2Fe2 tetrahedra, edges with two equivalent O(1)Ba4Fe2 octahedra, and faces with four equivalent O(1)Ba4Fe2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Fe(1), and one Fe(2) atom. In the third O site, O(3) is bonded to two equivalent Ba(1) and two equivalent Fe(2) atoms to form distorted OBa2Fe2 tetrahedra that share corners with eight equivalent O(1)Ba4Fe2 octahedra and corners with two equivalent O(3)Ba2Fe2 tetrahedra. The corner-sharing octahedral tilt angles range from 16-81°.