As2O3
Arsenic trioxide · Arsenous oxide, Arsenous anhydride
Arsenic trioxide is a thermodynamically stable, wide-gap insulating oxide widely recognized for its structural diversity and industrial utility.
About Arsenic trioxide
Arsenic trioxide is a prominent inorganic compound that exists as a thermodynamically stable phase on the convex hull. Characterized by its wide-gap insulating electronic nature, it exhibits significant structural complexity, as evidenced by the extensive number of reported crystal structures across major databases.
Its importance spans from historical industrial applications to modern pharmacological uses. The compound serves as a fundamental precursor in the production of various arsenic-based materials and remains a subject of intense study due to its distinct chemical properties and reactivity.
Key Properties
Cross-validated computational properties for Arsenic trioxide, aggregated across 6 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 As2O3. 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 As2O3, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 3.96 | 0.0000 | -6.463 | 4.12 |
| — | — | 3.44 | 0.0000 | -1.446 | — |
| P21 (No. 4) | monoclinic | 3.37 | 0.0000 | -1.269 | — |
| P21/c (No. 14) | monoclinic | 3.82 | 0.0016 | -1.268 | — |
| P21/c (No. 14) | monoclinic | 3.63 | 0.0017 | -6.462 | 3.90 |
| P21/c (No. 14) | monoclinic | 3.62 | 0.0022 | -6.461 | 3.94 |
| Fd-3m (No. 227) | cubic | 4.02 | 0.0026 | -6.461 | 3.79 |
| P21 (No. 4) | monoclinic | 3.75 | 0.0061 | -6.457 | 3.94 |
| P21/c (No. 14) | monoclinic | 3.41 | 0.0075 | -1.262 | — |
| P21/c (No. 14) | monoclinic | 3.46 | 0.0078 | -6.455 | 3.63 |
| Fd-3m (No. 227) | cubic | 4.15 | 0.0088 | -1.261 | — |
| — | — | 3.79 | 0.0103 | -1.436 | — |
Applications
Where Arsenic trioxide is used.
Frequently Asked Questions
Common questions about Arsenic trioxide, answered from cross-validated data.
What is As2O3?
Arsenic trioxide is a thermodynamically stable, wide-gap insulating oxide widely recognized for its structural diversity and industrial utility.
What is As2O3 used for?
What is the band gap of As2O3?
Is As2O3 a metal, semiconductor, or insulator?
Is As2O3 thermodynamically stable?
What is the crystal structure of As2O3?
What is the density of As2O3?
How many polymorphs of As2O3 are known?
What elements does As2O3 contain?
Where does the data for As2O3 come from?
How It Compares
As a highly studied and well-characterized inorganic oxide, this compound serves as a primary reference point for arsenic-based chemistry. Its position on the convex hull ensures it is a robust and stable material, distinguishing it as a reliable subject for structural analysis and chemical synthesis compared to less stable or transient arsenic species.
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)
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (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)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
Analyze As2O3 in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →