Cr8O21
This compound is a mixed-valence chromium oxide that exists as a solid phase in the chromium-oxygen system. It is primarily studied for its structural properties and its role in the oxidation chemistry of chromium materials.
Key Properties
Cross-validated computational properties for Cr8O21, aggregated across 3 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Reported Structures
Lowest-energy structures reported for Cr8O21, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| P-1 (No. 2) | triclinic | 1.70 | 0.0325 | -7.932 | 2.92 |
| P-1 (No. 2) | triclinic | 0.85 | 0.5163 | -7.448 | 2.82 |
| P-1 (No. 2) | triclinic | 0.00 | 1.0300 | -6.934 | 2.79 |
| P-1 (No. 2) | triclinic | 0.00 | 2.0811 | -5.883 | 2.79 |
| P-1 (No. 2) | — | — | — | — | — |
| P-1 (No. 2) | — | — | — | — | — |
| — | — | — | — | — | 2.75 |
Applications
Where Cr8O21 is used.
Frequently Asked Questions
Common questions about Cr8O21, answered from cross-validated data.
What is Cr8O21?
This compound is a mixed-valence chromium oxide that exists as a solid phase in the chromium-oxygen system. It is primarily studied for its structural properties and its role in the oxidation chemistry of chromium materials.
What is Cr8O21 used for?
What is the band gap of Cr8O21?
Is Cr8O21 a metal, semiconductor, or insulator?
Is Cr8O21 thermodynamically stable?
What is the crystal structure of Cr8O21?
What is the density of Cr8O21?
How many polymorphs of Cr8O21 are known?
What elements does Cr8O21 contain?
Where does the data for Cr8O21 come from?
Related Compounds
Other Spinel Oxide Catalysts in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- aflow — Data from AFLOW. Cite: Curtarolo et al., Comp. Mater. Sci. 58, 218 (2012).
- omat24 — Data from OMat24 (Meta FAIR). Cite: Barroso-Luque et al., arXiv 2410.12771 (2024).
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