Materials Data on Ca(FeO2)2 by Materials Project

Abstract

CaFe2O4 is Spinel structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with twelve FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are two shorter (2.18 Å) and two longer (2.20 Å) Ca–O bond lengths. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CaO4 tetrahedra and edges with six FeO6 octahedra. There are two shorter (2.02 Å) and four longer (2.09 Å) Fe–O bond lengths. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CaO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.08 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CaO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.18 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CaO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.09 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the second O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the third O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the fourth O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra.