K3AlF6
Potassium hexafluoroaluminate · Potassium fluoroaluminate, Elpasolite
K3AlF6 is a stable, insulating inorganic salt frequently employed as a fluxing agent in metallurgical and industrial manufacturing processes.
About Potassium hexafluoroaluminate
Potassium hexafluoroaluminate is a robust, thermodynamically stable inorganic compound characterized by its insulating electronic properties. Its structural integrity is well-documented across multiple experimental databases, reflecting a highly stable configuration that persists under standard conditions.
This material serves as a critical component in high-temperature industrial processes, particularly where chemical fluxing or surface modification is required. Its wide-gap nature and chemical stability make it an essential additive in metallurgical treatments and the production of specialized materials.
Key Properties
Cross-validated computational properties for Potassium hexafluoroaluminate, 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 K3AlF6. 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 K3AlF6, 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/m (No. 87) | tetragonal | 7.65 | 0.0000 | -5.283 | 2.86 |
| — | — | 7.26 | 0.0000 | -3.393 | — |
| Fm-3m (No. 225) | cubic | 6.79 | 0.0000 | -3.360 | — |
| — | — | 7.16 | 0.0042 | -3.389 | — |
| — | — | 7.11 | 0.0113 | -3.382 | — |
| Fm-3m (No. 225) | cubic | 6.30 | 0.0182 | -5.265 | 2.77 |
| — | — | 7.33 | 0.0344 | -3.359 | — |
| — | — | 7.33 | 0.0356 | -3.358 | — |
| I41/a (No. 88) | tetragonal | — | — | — | 2.85 |
| Fm-3m (No. 225) | cubic | — | — | — | 2.60 |
| Fm-3m (No. 225) | cubic | — | — | — | 2.72 |
| Fm-3m (No. 225) | cubic | — | — | — | 2.70 |
Applications
Where Potassium hexafluoroaluminate is used.
Frequently Asked Questions
Common questions about Potassium hexafluoroaluminate, answered from cross-validated data.
What is K3AlF6?
K3AlF6 is a stable, insulating inorganic salt frequently employed as a fluxing agent in metallurgical and industrial manufacturing processes.
What is K3AlF6 used for?
What is the band gap of K3AlF6?
Is K3AlF6 a metal, semiconductor, or insulator?
Is K3AlF6 thermodynamically stable?
What is the crystal structure of K3AlF6?
What is the density of K3AlF6?
How many polymorphs of K3AlF6 are known?
What elements does K3AlF6 contain?
Where does the data for K3AlF6 come from?
How It Compares
As a stable fluoride-based complex, this compound represents a fundamental archetype for alkali-aluminum halide systems, providing a reliable reference point for structural and chemical behavior in this class of materials.
Data sources & attribution
- 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)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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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