Materials Data on Na4Fe2O5 by Materials Project
Na4Fe2O5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.38–2.87 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.79 Å. In the third Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with three FeO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, edges with two equivalent FeO4 tetrahedra, and edges with two NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.44–2.69 Å. In the fourth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with four FeO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, edges with two FeO4 tetrahedra, and edges with two NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.28–2.57 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three FeO4 tetrahedra, corners with five NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 1.85–1.94 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three FeO4 tetrahedra, corners with two NaO5 trigonal bipyramids, and edges with three NaO5 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.85–1.94 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Fe3+ atom to form a mixture of distorted edge and corner-sharing ONa5Fe octahedra. The corner-sharing octahedra tilt angles range from 42–52°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Fe3+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+ and two equivalent Fe3+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+ and two equivalent Fe3+ atoms. In the fifth O2- site, O2- is bonded to five Na1+ and one Fe3+ atom to form a mixture of edge and corner-sharing ONa5Fe octahedra. The corner-sharing octahedra tilt angles range from 42–52°.