UCl5
Uranium pentachloride is a stable, semiconducting binary halide of uranium used primarily in fundamental actinide research.
About UCl5
Uranium pentachloride is a distinct binary halide compound composed of uranium and chlorine. As a semiconducting material that sits on the thermodynamic convex hull, it represents a stable configuration within the actinide halide family, making it a significant subject for fundamental solid-state research.
Its electronic character and stability profile make it an important reference point for understanding the bonding and chemical behavior of higher-valence uranium species. The compound has been extensively characterized across multiple structural databases, reflecting its importance in inorganic chemistry investigations.
Key Properties
Cross-validated computational properties for UCl5, 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.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of UCl5. 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 UCl5, 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. |
|---|---|---|---|---|---|
| P-1 (No. 2) | triclinic | 0.38 | 0.0000 | -1.653 | — |
| — | — | 0.35 | 0.0000 | -1.909 | — |
| P21/c (No. 14) | monoclinic | 0.00 | 0.0000 | -5.559 | 3.56 |
| P-1 (No. 2) | triclinic | 0.62 | 0.0007 | -5.558 | 3.59 |
| — | — | — | 0.0450 | -1.864 | — |
| P-1 (No. 2) | triclinic | 0.25 | 3.0401 | -2.518 | 3.08 |
| P21/c (No. 14) | monoclinic | — | — | — | 3.81 |
| P-1 (No. 2) | triclinic | — | — | — | 3.08 |
| P21/c (No. 14) | monoclinic | — | — | — | 3.33 |
| P-1 (No. 2) | triclinic | — | — | — | 3.12 |
| P-1 (No. 2) | triclinic | — | — | — | 3.15 |
| P21/c (No. 14) | monoclinic | — | — | — | 3.28 |
Applications
Where UCl5 is used.
Frequently Asked Questions
Common questions about UCl5, answered from cross-validated data.
What is UCl5?
Uranium pentachloride is a stable, semiconducting binary halide of uranium used primarily in fundamental actinide research.
What is UCl5 used for?
What is the band gap of UCl5?
Is UCl5 a metal, semiconductor, or insulator?
Is UCl5 thermodynamically stable?
What is the crystal structure of UCl5?
What is the density of UCl5?
How many polymorphs of UCl5 are known?
What elements does UCl5 contain?
Where does the data for UCl5 come from?
How It Compares
As a binary actinide halide, uranium pentachloride serves as a critical benchmark for evaluating the stability and electronic properties of high-oxidation-state uranium complexes in the absence of other directly comparable compounds in this specific structural class.
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)
- 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.
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