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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CaFeAsO5 by Materials Project

CaFeAsO5 is Esseneite-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.27–2.75 Å. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four equivalent AsO4 tetrahedra and edges with two equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.90–2.17 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 39–60°. There are a spread of As–O bond distances ranging from 1.70–1.76 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Fe3+, and one As5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one As5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Fe3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Fe3+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Ca2+ and two equivalent Fe3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaFeAs2O7 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaFe2(AsO5)2 by Materials Project

CaFe2(AsO5)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca is bonded to six O atoms to form CaO6 octahedra that share corners with four equivalent FeO6 octahedra and corners with six equivalent AsO4 tetrahedra. The corner-sharing octahedral tilt angles are 59°. There are two shorter (2.40 Å) and four longer (2.47 Å) Ca–O bond lengths. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four equivalent AsO4 tetrahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Fe–O bond distances ranging from 1.87–2.08 Å. As is bonded to four O atoms to form AsO4 tetrahedra that share corners with three equivalent CaO6 octahedra and corners with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 47–66°. There are a spread of As–O bond distances ranging from 1.68–1.77 Å. There are four inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Ca and one As atom. In the second O site, O is bonded in a trigonal planar geometry to one Ca, one Fe, and one As atom. In the third O site, O is bonded in a water-like geometry to two equivalent Fe atoms. In the fourth O site, O is bonded in a 3-coordinate geometry to two equivalent Fe and one As atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaFe2(AsO5)2 by Materials Project

CaFe2(AsO5)2 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded in a 8-coordinate geometry to eight O atoms. There are four shorter (2.39 Å) and four longer (2.80 Å) Ca–O bond lengths. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with four equivalent FeO6 octahedra and corners with six AsO4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. There are two shorter (2.33 Å) and four longer (2.44 Å) Ca–O bond lengths. Fe is bonded to six O atoms to form FeO6 octahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one FeO6 octahedra, corners with four AsO4 tetrahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 47–58°. There are a spread of Fe–O bond distances ranging from 1.91–2.10 Å. There are two inequivalent As sites. In the first As site, As is bonded to four O atoms to form AsO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–66°. There are a spread of As–O bond distances ranging from 1.67–1.76 Å. In the second As site, As is bonded to four O atoms to form AsO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 42–62°. There is two shorter (1.71 Å) and two longer (1.73 Å) As–O bond length. There are seven inequivalent O sites. In the first O site, O is bonded in a trigonal planar geometry to one Ca, one Fe, and one As atom. In the second O site, O is bonded in a trigonal planar geometry to one Ca, one Fe, and one As atom. In the third O site, O is bonded in a water-like geometry to two equivalent Fe atoms. In the fourth O site, O is bonded in a bent 120 degrees geometry to two equivalent Fe atoms. In the fifth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Fe and one As atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Ca and one As atom. In the seventh O site, O is bonded in a 2-coordinate geometry to one Ca, one Fe, and one As atom.

36 MATERIALS SCIENCE↗