KF
Potassium fluoride · Potassium monofluoride
Potassium fluoride is a stable, insulating salt widely used as a source of fluoride ions in industrial and laboratory chemical applications.
About Potassium fluoride
Potassium fluoride is a thermodynamically stable inorganic salt that functions as a wide-band-gap insulator. Its robust structural integrity is evidenced by its prevalence in materials research, where it serves as a fundamental building block for various chemical processes.
Due to its high stability and unique reactivity, this compound is widely employed in industrial applications ranging from organic synthesis to the manufacturing of specialized glass and metal fluxes. It remains a critical reagent in laboratories requiring reliable fluoride ion sources.
Key Properties
Cross-validated computational properties for Potassium fluoride, 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 KF. 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 KF, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 6.46 | 0.0000 | -2.926 | — |
| Fm-3m (No. 225) | cubic | 5.95 | 0.0000 | -4.447 | 2.58 |
| — | — | 6.76 | 0.0002 | -2.913 | — |
| — | — | 6.74 | 0.0004 | -2.913 | — |
| — | — | 6.75 | 0.0018 | -2.912 | — |
| — | — | 6.74 | 0.0027 | -2.911 | — |
| — | — | 6.73 | 0.0028 | -2.911 | — |
| — | — | 6.23 | 0.0344 | -2.879 | — |
| — | — | 6.25 | 0.0373 | -2.876 | — |
| — | — | 6.64 | 0.0418 | -2.872 | — |
| Pm-3m (No. 221) | cubic | 7.11 | 0.0618 | -2.864 | — |
| — | — | 5.97 | 0.0619 | -2.851 | — |
Applications
Where Potassium fluoride is used.
Frequently Asked Questions
Common questions about Potassium fluoride, answered from cross-validated data.
What is KF?
Potassium fluoride is a stable, insulating salt widely used as a source of fluoride ions in industrial and laboratory chemical applications.
What is KF used for?
What is the band gap of KF?
Is KF a metal, semiconductor, or insulator?
Is KF thermodynamically stable?
What is the crystal structure of KF?
How many polymorphs of KF are known?
What elements does KF contain?
Where does the data for KF come from?
How It Compares
As a highly stable and well-documented halide, this compound serves as a baseline reference for alkali metal fluorides, representing a standard in ionic crystal behavior and thermodynamic reliability within its chemical family.
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)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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