Materials Data on Ca(FeO2)2 by Materials Project

Abstract

CaFe2O4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to two Fe3+ and four O2- atoms. There is one shorter (1.88 Å) and one longer (1.96 Å) Ca–Fe bond length. There are a spread of Ca–O bond distances ranging from 1.85–2.47 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to two Fe3+ and four O2- atoms. There is one shorter (1.89 Å) and one longer (1.96 Å) Ca–Fe bond length. There are a spread of Ca–O bond distances ranging from 1.84–2.48 Å. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded in a 8-coordinate geometry to two Ca2+ and six O2- atoms. There are a spread of Fe–O bond distances ranging from 2.16–2.56 Å. In the second Fe3+ site, Fe3+ is bonded in a distorted body-centered cubic geometry to two Ca2+ and six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.99–2.57 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted edge-sharing FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.60–2.22 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form edge-sharing FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.13–2.54 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+ and three Fe3+ atoms.