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Cr2SiO4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Cr2+ is bonded in a 4-coordinate geometry to six equivalent O2- atoms. There are a spread of Cr–O bond distances ranging from 2.04–2.75 Å. Si4+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All Si–O bond lengths are 1.65 Å. O2- is bonded in a 3-coordinate geometry to three equivalent Cr2+ and one Si4+ atom.
Cr4Si4O13 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Cr+2.50+ sites. In the first Cr+2.50+ site, Cr+2.50+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cr–O bond distances ranging from 2.04–2.52 Å. In the second Cr+2.50+ site, Cr+2.50+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six SiO4 tetrahedra and an edgeedge with one CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.95–2.21 Å. In the third Cr+2.50+ site, Cr+2.50+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cr–O bond distances ranging from 2.07–2.28 Å. In the fourth Cr+2.50+ site, Cr+2.50+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with four SiO4 tetrahedra, an edgeedge with one CrO6 octahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.99–2.16 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent CrO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two CrO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Si–O bond distances ranging from 1.60–1.64 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CrO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–62°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three CrO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–62°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.50+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.50+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.50+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Cr+2.50+ and one Si4+ atom. In the fifth O2- site, O2- is bonded to three Cr+2.50+ and one Si4+ atom to form distorted edge-sharing OCr3Si tetrahedra. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Cr+2.50+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Cr+2.50+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Cr+2.50+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Cr+2.50+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.50+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms.
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
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