TmO3
TmO3 is an unstable, semiconducting thulium oxide that serves as a specialized subject for research into non-equilibrium materials.
About TmO3
TmO3 is a semiconducting oxide composed of thulium and oxygen. As a rare-earth oxide variant, it represents a complex structural arrangement that deviates from the more common stable oxide stoichiometries found in the lanthanide series.
Because it exists above the thermodynamic hull, this compound is considered an unstable phase under standard conditions. Its presence in multiple databases highlights its role as a subject of interest for researchers investigating non-equilibrium oxide structures and high-energy synthetic pathways.
Key Properties
Cross-validated computational properties for TmO3, 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 TmO3, 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. |
|---|---|---|---|---|---|
| P63/m (No. 176) | hexagonal | 0.20 | 0.4616 | -6.926 | 6.06 |
| Fm-3m (No. 225) | cubic | 0.00 | 0.5646 | -6.823 | 8.57 |
| Fm-3m (No. 225) | — | — | — | — | — |
| Pm (No. 6) | Monoclinic | — | — | — | 6.83 |
| Pm (No. 6) | Monoclinic | — | — | — | 8.07 |
| Cm (No. 8) | Monoclinic | — | — | — | 7.55 |
| Pm (No. 6) | Monoclinic | — | — | — | 7.95 |
| Cm (No. 8) | Monoclinic | — | — | — | 6.28 |
| Cm (No. 8) | Monoclinic | — | — | — | 7.50 |
Frequently Asked Questions
Common questions about TmO3, answered from cross-validated data.
What is TmO3?
TmO3 is an unstable, semiconducting thulium oxide that serves as a specialized subject for research into non-equilibrium materials.
What is the band gap of TmO3?
Is TmO3 a metal, semiconductor, or insulator?
Is TmO3 thermodynamically stable?
What is the crystal structure of TmO3?
What is the density of TmO3?
How many polymorphs of TmO3 are known?
What elements does TmO3 contain?
Where does the data for TmO3 come from?
How It Compares
As a rare-earth oxide that does not conform to the typical stable stoichiometry of its class, TmO3 serves as a unique case study in structural instability compared to the highly stable, naturally occurring oxides of the lanthanide group.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- mpaloe — Data from mpaloe.
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