ScO2
ScO2 is a semiconducting scandium oxide that is typically unstable under standard conditions but remains a subject of intense computational study.
About ScO2
ScO2 is a semiconducting oxide of scandium that exists as a metastable phase. Due to its position above the thermodynamic hull, it is generally considered unstable under standard conditions, representing a challenging target for experimental synthesis compared to more common scandium oxides.
Despite its instability, the compound has garnered significant attention in computational materials science. With hundreds of reported structures across major databases, it serves as a critical case study for understanding phase stability and the complex bonding environments possible in transition metal oxides.
Key Properties
Cross-validated computational properties for ScO2, 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 ScO2, 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. |
|---|---|---|---|---|---|
| Pnma (No. 62) | orthorhombic | 0.59 | 0.2723 | -8.444 | 2.90 |
| Pnnm (No. 58) | orthorhombic | 0.30 | 0.2744 | -8.442 | 3.54 |
| Cmcm (No. 63) | orthorhombic | 0.00 | 0.3282 | -8.389 | 3.30 |
| Aea2 (No. 41) | Orthorhombic | — | — | — | 4.70 |
| P1 (No. 1) | Triclinic | — | — | — | 3.75 |
| C2 (No. 5) | Monoclinic | — | — | — | 3.51 |
| C2/m (No. 12) | Monoclinic | — | — | — | 3.74 |
| C2/m (No. 12) | Monoclinic | — | — | — | 4.43 |
| C2/m (No. 12) | Monoclinic | — | — | — | 4.82 |
| P-1 (No. 2) | Triclinic | — | — | — | 4.00 |
| P63/mmc (No. 194) | Hexagonal | — | — | — | 3.59 |
| P63/mmc (No. 194) | Hexagonal | — | — | — | 3.55 |
Applications
Where ScO2 is used.
Frequently Asked Questions
Common questions about ScO2, answered from cross-validated data.
What is ScO2?
ScO2 is a semiconducting scandium oxide that is typically unstable under standard conditions but remains a subject of intense computational study.
What is ScO2 used for?
What is the band gap of ScO2?
Is ScO2 a metal, semiconductor, or insulator?
Is ScO2 thermodynamically stable?
What is the crystal structure of ScO2?
What is the density of ScO2?
How many polymorphs of ScO2 are known?
What elements does ScO2 contain?
Where does the data for ScO2 come from?
How It Compares
As a metastable semiconducting phase, ScO2 occupies a unique niche in the landscape of scandium-based materials. While it lacks the thermodynamic robustness of standard scandium sesquioxide, its high structural diversity makes it a focal point for researchers investigating non-equilibrium oxide phases.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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