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 six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.70 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.91 Å. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share corners with four FeO6 octahedra and edges with two equivalent FeO5 square pyramids. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Fe–O bond distances ranging from 1.95–2.10 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO5 square pyramids and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.11 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO5 square pyramids and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.13 Å. In the fourth Fe3+ site, Fe3+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share corners with four FeO6 octahedra and edges with two equivalent FeO5 square pyramids. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Fe–O bond distances ranging from 1.96–2.10 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Fe3+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Ca2+ and three Fe3+ atoms to form distorted edge-sharing OCa2Fe3 trigonal bipyramids. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Fe3+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Ca2+ and three Fe3+ atoms to form distorted edge-sharing OCa2Fe3 square pyramids.