Results for “Ca-Fe-O-Si”

DOE OSTI2020

Materials Data on CaFe(SiO3)2 by Materials Project

CaFeSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c 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 2.35–2.83 Å. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent SiO4 tetrahedra and edges with two equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.12–2.19 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent FeO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–58°. There are a spread of Si–O bond distances ranging from 1.61–1.70 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Fe2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Fe2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+ and two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on CaFe(SiO3)2 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 CaFe3Si2O9 by Materials Project

CaFe3Si2O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.27–2.53 Å. There are two inequivalent Fe+2.67+ sites. In the first Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with three SiO4 tetrahedra, and edges with five FeO6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are a spread of Fe–O bond distances ranging from 1.88–2.24 Å. In the second Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with five SiO4 tetrahedra and edges with four equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.93–2.30 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with five FeO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–63°. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six FeO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–65°. There are a spread of Si–O bond distances ranging from 1.65–1.68 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Fe+2.67+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Fe+2.67+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.67+ and one Si4+ atom. In the fifth O2- site, O2- is bonded to five Fe+2.67+ atoms to form edge-sharing OFe5 square pyramids. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Fe+2.67+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+, two Fe+2.67+, and one Si4+ atom.

36 MATERIALS SCIENCE↗