DOI: 10.17188/1296502
title: Materials Data on Na(Fe2O3)4 by Materials Project

description: Na(Fe2O3)4 is Spinel-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. There are two shorter (2.21 Å) and four longer (2.25 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent FeO4 tetrahedra and edges with six FeO6 octahedra. There are four shorter (2.24 Å) and two longer (2.25 Å) Na–O bond lengths. There are seven inequivalent Fe+2.88+ sites. In the first Fe+2.88+ site, Fe+2.88+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, an edgeedge with one NaO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.03–2.18 Å. In the second Fe+2.88+ site, Fe+2.88+ is bonded to four O2- atoms to form FeO4 tetrahedra that share a cornercorner with one NaO6 octahedra and corners with eleven FeO6 octahedra. The corner-sharing octahedra tilt angles range from 54–60°. There is one shorter (1.88 Å) and three longer (1.98 Å) Fe–O bond length. In the third Fe+2.88+ site, Fe+2.88+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent NaO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.08 Å. In the fourth Fe+2.88+ site, Fe+2.88+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with two equivalent NaO6 octahedra and corners with ten FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–63°. There are a spread of Fe–O bond distances ranging from 1.88–2.04 Å. In the fifth Fe+2.88+ site, Fe+2.88+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three equivalent NaO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There is three shorter (1.91 Å) and one longer (2.03 Å) Fe–O bond length. In the sixth Fe+2.88+ site, Fe+2.88+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, an edgeedge with one NaO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.11 Å. In the seventh Fe+2.88+ site, Fe+2.88+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, an edgeedge with one NaO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.11 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Na1+ and three Fe+2.88+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.88+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.88+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Na1+ and three Fe+2.88+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.88+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.88+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe+2.88+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Na1+ and three Fe+2.88+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Na1+ and three Fe+2.88+ atoms.