SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
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
Bi2Fe4O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO4 tetrahedra and edges with two equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.07 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent FeO6 octahedra and a cornercorner with one FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Fe–O bond distances ranging from 1.86–1.94 Å. In the third Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent FeO6 octahedra and a cornercorner with one FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–64°. There are a spread of Fe–O bond distances ranging from 1.87–1.93 Å. Bi3+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.15–3.07 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe3+ and two equivalent Bi3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe3+ and two equivalent Bi3+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Fe3+ and two equivalent Bi3+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to two Fe3+ atoms.