Cr3O4
Cr3O4 is a metastable semiconducting spinel oxide used in research for its unique electronic and catalytic properties.
About Cr3O4
Cr3O4 is a semiconducting spinel oxide that represents a complex phase within the chromium-oxygen system. Due to its metastable nature, it offers unique structural characteristics that distinguish it from more conventional, highly stable oxide phases, making it a subject of interest for fundamental materials research.
As a member of the spinel oxide class, this compound is investigated for its potential in catalytic processes where surface electronic properties are critical. Its ability to host multiple oxidation states of chromium allows for versatile interactions in chemical environments, providing a platform for studying redox-active surface mechanisms.
Key Properties
Cross-validated computational properties for Cr3O4, aggregated across 4 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.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of Cr3O4. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for Cr3O4, 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. |
|---|---|---|---|---|---|
| C2/c (No. 15) | monoclinic | 0.97 | 0.0830 | -9.135 | 4.67 |
| P-1 (No. 2) | triclinic | 1.48 | 0.0992 | -9.119 | 4.67 |
| Cmmm (No. 65) | orthorhombic | 0.00 | 0.1878 | -1.817 | — |
| Cmmm (No. 65) | orthorhombic | 0.00 | 0.1995 | -1.806 | — |
| P1 (No. 1) | triclinic | — | — | — | 5.61 |
| P-1 (No. 2) | triclinic | — | — | — | 4.80 |
| P-1 (No. 2) | triclinic | — | — | — | 6.49 |
| P-1 (No. 2) | triclinic | — | — | — | 6.32 |
| Cm (No. 8) | monoclinic | — | — | — | 4.39 |
| P-1 (No. 2) | triclinic | — | — | — | 6.00 |
| Pm (No. 6) | monoclinic | — | — | — | 4.78 |
| Cm (No. 8) | monoclinic | — | — | — | 4.31 |
Applications
Where Cr3O4 is used.
Frequently Asked Questions
Common questions about Cr3O4, answered from cross-validated data.
What is Cr3O4?
Cr3O4 is a metastable semiconducting spinel oxide used in research for its unique electronic and catalytic properties.
What is Cr3O4 used for?
What is the band gap of Cr3O4?
Is Cr3O4 a metal, semiconductor, or insulator?
Is Cr3O4 thermodynamically stable?
What is the crystal structure of Cr3O4?
What is the density of Cr3O4?
How many polymorphs of Cr3O4 are known?
What elements does Cr3O4 contain?
Where does the data for Cr3O4 come from?
How It Compares
Unlike the highly stable and widely utilized MgAl2O4 or the simple binary oxides like NiO and ZnO, Cr3O4 exists in a metastable state that requires precise synthesis conditions. While perovskite-structured siblings such as LaMnO3 or LaNiO3 are frequently studied for their robust electrocatalytic performance, Cr3O4 offers a distinct structural alternative that bridges the gap between simple binary oxides and more complex mixed-metal spinel systems.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- aflow — Data from AFLOW (aflow.org). Cite: Curtarolo et al., Comp. Mater. Sci. 58, 218 (2012). (CC-BY-4.0)
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