Materials Data on Sr2Fe2O5 by Materials Project

Sr2Fe2O5 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.41–3.22 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four equivalent FeO6 octahedra and corners with two equivalent FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 4–8°. There are a spread of Fe–O bond distances ranging from 1.99–2.24 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form distorted FeO4 tetrahedra that share corners with two equivalent FeO6 octahedra and an edgeedge with one FeO4 tetrahedra. The corner-sharing octahedral tilt angles are 29°. There are a spread of Fe–O bond distances ranging from 1.89–1.97 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Fe3+ atoms to form distorted OSr4Fe2 octahedra that share corners with two equivalent OSr4Fe2 octahedra, corners with four equivalent OSr2Fe2 trigonal pyramids, edges with two equivalent OSr4Fe2 octahedra, and faces with four equivalent OSr4Fe2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Fe3+ atoms to form distorted OSr4Fe2 octahedra that share corners with two equivalent OSr4Fe2 octahedra, corners with four equivalent OSr2Fe2 trigonal pyramids, edges with two equivalent OSr4Fe2 octahedra, and faces with four equivalent OSr4Fe2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third O2- site, O2- is bonded in a 4-coordinate geometry to four equivalent Sr2+ and two Fe3+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Sr2+ and two equivalent Fe3+ atoms to form OSr2Fe2 trigonal pyramids that share corners with eight OSr4Fe2 octahedra and an edgeedge with one OSr2Fe2 trigonal pyramid. The corner-sharing octahedra tilt angles range from 26–74°.