ThO2
Thorium dioxide · Thoria
Thorium dioxide is a highly stable, heat-resistant ceramic oxide used primarily in nuclear fuel and advanced industrial applications.

About Thorium dioxide
Thorium dioxide is a robust, thermodynamically stable ceramic material characterized by its insulating electronic nature. Due to its exceptional thermal resilience and chemical inertness, it remains a cornerstone in high-temperature applications and specialized industrial processes.
As a highly studied oxide, this compound is recognized for its structural reliability and consistent performance under extreme conditions. Its status as a stable phase on the convex hull underscores its utility in demanding environments where material degradation must be strictly minimized.
Key Properties
Cross-validated computational properties for Thorium dioxide, 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 ThO2, 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 | 4.42 | 0.0000 | -10.138 | 9.98 |
| Pnma (No. 62) | orthorhombic | 3.52 | 0.1497 | -9.988 | 10.49 |
| P1 (No. 1) | Triclinic | — | — | — | 10.55 |
| P-1 (No. 2) | Triclinic | — | — | — | 13.79 |
| P21/m (No. 11) | Monoclinic | — | — | — | 13.53 |
| P-1 (No. 2) | Triclinic | — | — | — | 12.35 |
| P21 (No. 4) | Monoclinic | — | — | — | 7.96 |
| P21/m (No. 11) | Monoclinic | — | — | — | 12.03 |
| P-3m1 (No. 164) | Trigonal | — | — | — | 5.14 |
| P-1 (No. 2) | Triclinic | — | — | — | 7.25 |
| P-1 (No. 2) | Triclinic | — | — | — | 12.34 |
| Pnma (No. 62) | Orthorhombic | — | — | — | 10.49 |
Applications
Where Thorium dioxide is used.
Frequently Asked Questions
Common questions about Thorium dioxide, answered from cross-validated data.
What is ThO2?
Thorium dioxide is a highly stable, heat-resistant ceramic oxide used primarily in nuclear fuel and advanced industrial applications.
What is ThO2 used for?
What is the band gap of ThO2?
Is ThO2 a metal, semiconductor, or insulator?
Is ThO2 thermodynamically stable?
What is the crystal structure of ThO2?
What is the density of ThO2?
How many polymorphs of ThO2 are known?
What elements does ThO2 contain?
Where does the data for ThO2 come from?
How It Compares
As a primary oxide of thorium, this material serves as a benchmark for stability and performance within its chemical class, offering superior thermal characteristics that make it a standard reference for high-temperature insulating oxides.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
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