AcBr3
Actinium tribromide is a thermodynamically stable, insulating actinide halide used primarily in fundamental chemical research.
About AcBr3
Actinium tribromide is a thermodynamically stable inorganic halide composed of actinium and bromine. As a wide-gap insulator, it exhibits distinct electronic characteristics typical of heavy actinide salts, reflecting the unique bonding nature of the actinium center.
This compound is a subject of significant interest in fundamental actinide research due to its structural diversity. With multiple reported crystal structures across major databases, it serves as a key reference point for understanding the coordination chemistry and stability of actinium-based materials.
Key Properties
Cross-validated computational properties for AcBr3, 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 AcBr3. 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 AcBr3, 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 | 4.19 | 0.0000 | -2.186 | — |
| — | — | 4.14 | 0.0000 | -2.333 | — |
| P63/m (No. 176) | hexagonal | 4.10 | 0.0000 | -4.753 | 5.68 |
| — | — | 4.17 | 0.0003 | -2.333 | — |
| — | — | 0.00 | 0.0282 | -2.305 | — |
| — | — | 2.79 | 0.2894 | -2.044 | — |
| — | — | 2.52 | 0.3231 | -2.010 | — |
| — | — | 2.83 | 0.3439 | -1.989 | — |
| — | — | 1.41 | 0.4620 | -1.871 | — |
| C2/m (No. 12) | monoclinic | — | — | — | 6.23 |
| Pmmn (No. 59) | orthorhombic | — | — | — | 4.72 |
| R-3m (No. 166) | trigonal | — | — | — | 4.89 |
Applications
Where AcBr3 is used.
Frequently Asked Questions
Common questions about AcBr3, answered from cross-validated data.
What is AcBr3?
Actinium tribromide is a thermodynamically stable, insulating actinide halide used primarily in fundamental chemical research.
What is AcBr3 used for?
What is the band gap of AcBr3?
Is AcBr3 a metal, semiconductor, or insulator?
Is AcBr3 thermodynamically stable?
What is the crystal structure of AcBr3?
How many polymorphs of AcBr3 are known?
What elements does AcBr3 contain?
Where does the data for AcBr3 come from?
How It Compares
As a specialized actinide halide, this compound occupies a unique position in materials science, serving as a fundamental benchmark for the behavior of actinium in halogenated environments.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- alexandria — Data from Alexandria. Cite: Schmidt et al., npj Comput. Mater. 10, 200 (2024). (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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