Ac2O3
actinium oxide · actinium(III) oxide
Actinium oxide is a stable, insulating binary compound of actinium and oxygen used primarily in fundamental actinide research.
About actinium oxide
Actinium oxide is a stable, insulating binary compound composed of actinium and oxygen. As a member of the actinide oxide family, it represents a fundamental material for understanding the chemical behavior of the heaviest elements in the periodic table. Its thermodynamic stability on the convex hull underscores its importance as a baseline structure for actinium-based chemistry.
This material is primarily studied for its unique electronic characteristics and its role in specialized nuclear research. Given its status as a rare and radioactive oxide, it serves as a critical subject for fundamental materials science investigations into the bonding and structural evolution of actinide systems.
Key Properties
Cross-validated computational properties for actinium oxide, aggregated across 5 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 Ac2O3. 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 Ac2O3, 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. |
|---|---|---|---|---|---|
| — | — | 3.88 | 0.0000 | -3.580 | — |
| P-3m1 (No. 164) | trigonal | 3.77 | 0.0000 | -3.583 | — |
| P-3m1 (No. 164) | trigonal | 3.52 | 0.0000 | -8.355 | 9.11 |
| — | — | 3.13 | 0.0348 | -3.545 | — |
| — | — | 3.13 | 0.0351 | -3.545 | — |
| — | — | 0.33 | 0.8482 | -2.732 | — |
| P-3m1 (No. 164) | trigonal | 3.52 | — | -7.943 | 8.98 |
| P-3m1 (No. 164) | trigonal | — | — | — | 9.18 |
Applications
Where actinium oxide is used.
Frequently Asked Questions
Common questions about actinium oxide, answered from cross-validated data.
What is Ac2O3?
Actinium oxide is a stable, insulating binary compound of actinium and oxygen used primarily in fundamental actinide research.
What is Ac2O3 used for?
What is the band gap of Ac2O3?
Is Ac2O3 a metal, semiconductor, or insulator?
Is Ac2O3 thermodynamically stable?
What is the crystal structure of Ac2O3?
How many polymorphs of Ac2O3 are known?
What elements does Ac2O3 contain?
Where does the data for Ac2O3 come from?
How It Compares
As a rare actinide oxide, this compound occupies a unique position in materials science, serving as a primary reference point for the behavior of actinium within oxide lattices. Unlike more common transition metal oxides, its chemistry is defined by the specific electronic configuration of the actinium ion, making it a foundational study for understanding the broader class of heavy element oxides.
Data sources & attribution
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- aflow — Data from AFLOW (aflow.org). Cite: Curtarolo et al., Comp. Mater. Sci. 58, 218 (2012). (CC-BY-4.0)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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