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CrO2 is trigonal omega-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three CrO2 sheets oriented in the (0, 0, 1) direction. Cr4+ is bonded to six equivalent O2- atoms to form edge-sharing CrO6 octahedra. All Cr–O bond lengths are 1.95 Å. O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Cr4+ atoms.
CrO2 is trigonal omega-like structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Cr4+ is bonded to six equivalent O2- atoms to form edge-sharing CrO6 octahedra. All Cr–O bond lengths are 1.95 Å. O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Cr4+ atoms.
CrO2 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–56°. There is two shorter (1.70 Å) and two longer (1.80 Å) Cr–O bond length. In the second Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six equivalent CrO4 tetrahedra and edges with two equivalent CrO6 octahedra. There are two shorter (2.00 Å) and four longer (2.04 Å) Cr–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cr4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr4+ atoms.
CrO2 is Hydrophilite-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.89–1.97 Å. In the second Cr4+ site, Cr4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.89–1.97 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr4+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Cr4+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Cr4+ atoms.
CrO2 crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–59°. There is three shorter (1.82 Å) and one longer (1.88 Å) Cr–O bond length. In the second Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with three equivalent CrO4 tetrahedra and edges with four equivalent CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.84–2.09 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to four Cr4+ atoms. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to three equivalent Cr4+ atoms. In the fourth O2- site, O2- is bonded in a water-like geometry to two equivalent Cr4+ atoms.
CrO2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cr4+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Cr–O bond lengths are 2.06 Å. O2- is bonded to four equivalent Cr4+ atoms to form a mixture of edge and corner-sharing OCr4 tetrahedra.
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
The time decay of magnetization in commercial CrO2, gamma-Fe2O3, and Co-doped gamma-Fe2O3 tapes is investigated experimentally at temperatures 6, 50, 100, 200, 250, and 300 K. The decay is found to be linearly dependent on temperature in all four tapes tested, but when the curves are extrapolated to 0 K, there is a large finite intercept - in contrast to similar measurements on ferromagnetic materials and rocks.