PmF3
Promethium trifluoride is a stable, insulating fluoride compound formed from the rare radioactive element promethium.
About PmF3
Promethium trifluoride is a thermodynamically stable inorganic compound composed of promethium and fluorine. As a wide-gap insulator, it exhibits the characteristic electronic properties typical of rare-earth halides, maintaining structural integrity within its chemical environment.
Its significance lies in its role as a representative fluoride of a rare radioactive element. Due to the scarcity and radioactivity of promethium, this compound is primarily studied in specialized laboratory settings to understand the fundamental chemical behaviors of the lanthanide series.
Key Properties
Cross-validated computational properties for PmF3, 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 PmF3. 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 PmF3, 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. |
|---|---|---|---|---|---|
| I4/mmm (No. 139) | tetragonal | 5.61 | 0.0000 | -4.159 | — |
| — | — | 5.26 | 0.0000 | -4.184 | — |
| I4/mmm (No. 139) | tetragonal | 4.98 | 0.0000 | -6.837 | 7.47 |
| — | — | 6.43 | 0.0144 | -4.169 | — |
| — | — | 6.24 | 0.1570 | -4.027 | — |
| — | — | 4.09 | 0.1603 | -4.023 | — |
| Cmmm (No. 65) | orthorhombic | 1.20 | 0.7163 | -3.442 | — |
| C2 (No. 5) | monoclinic | — | — | — | 6.98 |
| Cmm2 (No. 35) | orthorhombic | — | — | — | 5.00 |
| C2 (No. 5) | monoclinic | — | — | — | 6.69 |
| C2/m (No. 12) | monoclinic | — | — | — | 5.56 |
| C2/m (No. 12) | monoclinic | — | — | — | 7.12 |
Applications
Where PmF3 is used.
Frequently Asked Questions
Common questions about PmF3, answered from cross-validated data.
What is PmF3?
Promethium trifluoride is a stable, insulating fluoride compound formed from the rare radioactive element promethium.
What is PmF3 used for?
What is the band gap of PmF3?
Is PmF3 a metal, semiconductor, or insulator?
Is PmF3 thermodynamically stable?
What is the crystal structure of PmF3?
How many polymorphs of PmF3 are known?
What elements does PmF3 contain?
Where does the data for PmF3 come from?
How It Compares
As a rare-earth fluoride, this compound represents a specialized niche within the broader family of metal halides. It serves as a critical reference point for understanding the localized electronic behavior and structural stability of radioactive lanthanide compounds, which are distinct from the more common, non-radioactive members of the halide 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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