UO2
Uranium dioxide · Urania, Uranous oxide
Uranium dioxide is a black, crystalline powder that serves as the primary fuel for nuclear power reactors. It is valued for its stability at high temperatures and its ability to withstand the intense conditions found within a nuclear core.
Key Properties
Cross-validated computational properties for Uranium dioxide, 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.
Reported Structures
Lowest-energy structures reported for UO2, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 0.00 | 0.0000 | -10.813 | 11.06 |
| P42/mnm (No. 136) | tetragonal | 0.00 | 0.1258 | -10.687 | 9.46 |
| Cm (No. 8) | Monoclinic | — | — | — | 5.02 |
| P1 (No. 1) | Triclinic | — | — | — | 7.26 |
| C2 (No. 5) | Monoclinic | — | — | — | 8.30 |
| C2/m (No. 12) | Monoclinic | — | — | — | 10.63 |
| C2/m (No. 12) | Monoclinic | — | — | — | 10.06 |
| P-1 (No. 2) | Triclinic | — | — | — | 9.79 |
| Cm (No. 8) | Monoclinic | — | — | — | 7.39 |
| Cm (No. 8) | Monoclinic | — | — | — | 11.63 |
| Cm (No. 8) | Monoclinic | — | — | — | 9.33 |
| Fm-3m (No. 225) | — | — | — | — | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting UO2.
Applications
Where Uranium dioxide is used.
Frequently Asked Questions
Common questions about Uranium dioxide, answered from cross-validated data.
What is UO2?
Uranium dioxide is a black, crystalline powder that serves as the primary fuel for nuclear power reactors. It is valued for its stability at high temperatures and its ability to withstand the intense conditions found within a nuclear core.
What is UO2 used for?
What is the band gap of UO2?
Is UO2 a metal, semiconductor, or insulator?
Is UO2 thermodynamically stable?
What is the crystal structure of UO2?
What is the density of UO2?
How many polymorphs of UO2 are known?
How is UO2 synthesized?
What elements does UO2 contain?
Where does the data for UO2 come from?
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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