KAlF4
KAlF4 is a stable, insulating fluoride compound known for its structural variety and potential utility in advanced materials research.
About KAlF4
KAlF4 is a complex fluoride characterized by its wide-band-gap insulating electronic profile. As a thermodynamically stable phase, it occupies a secure position on the convex hull, indicating significant structural robustness under standard conditions.
With numerous reported structures across multiple databases, this compound serves as a key subject for understanding the coordination chemistry of aluminum-fluoride frameworks. Its stability and insulating nature make it an intriguing candidate for specialized applications in materials research.
Key Properties
Cross-validated computational properties for KAlF4, 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 KAlF4. 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 KAlF4, 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. |
|---|---|---|---|---|---|
| — | — | 7.74 | 0.0000 | -3.608 | — |
| P21/m (No. 11) | monoclinic | 7.30 | 0.0000 | -3.566 | — |
| P21/m (No. 11) | monoclinic | 6.91 | 0.0000 | -5.737 | 2.89 |
| — | — | 7.63 | 0.0010 | -3.607 | — |
| P4/mbm (No. 127) | tetragonal | 7.48 | 0.0012 | -3.565 | — |
| P4/mbm (No. 127) | tetragonal | 6.94 | 0.0042 | -5.733 | 3.04 |
| Pnma (No. 62) | orthorhombic | 8.03 | 0.0064 | -5.731 | 2.71 |
| — | — | 7.57 | 0.0095 | -3.598 | — |
| — | — | 7.75 | 0.0112 | -3.596 | — |
| — | — | 7.61 | 0.0128 | -3.595 | — |
| P4/mmm (No. 123) | tetragonal | 6.79 | 0.0134 | -5.724 | 2.94 |
| P4/mmm (No. 123) | tetragonal | 7.23 | 0.0135 | -3.552 | — |
Applications
Where KAlF4 is used.
Frequently Asked Questions
Common questions about KAlF4, answered from cross-validated data.
What is KAlF4?
KAlF4 is a stable, insulating fluoride compound known for its structural variety and potential utility in advanced materials research.
What is KAlF4 used for?
What is the band gap of KAlF4?
Is KAlF4 a metal, semiconductor, or insulator?
Is KAlF4 thermodynamically stable?
What is the crystal structure of KAlF4?
How many polymorphs of KAlF4 are known?
What elements does KAlF4 contain?
Where does the data for KAlF4 come from?
How It Compares
As a distinct fluoride compound, KAlF4 represents a foundational example of stable ternary aluminum-based halides. While it stands as a unique entity in this specific dataset, its structural diversity and thermodynamic stability provide a baseline for evaluating the behavior of similar complex fluoride systems.
Data sources & attribution
- 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)
- 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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