KNbF6
KNbF6 is a stable, insulating fluoride compound composed of potassium, niobium, and fluorine.
About KNbF6
KNbF6 is a complex fluoride compound characterized by its insulating electronic nature and wide-band-gap behavior. As a thermodynamically stable phase residing on the convex hull, it represents a robust crystalline arrangement within the landscape of inorganic fluorides.
Its structural integrity is underscored by its presence across multiple databases, reflecting significant interest in its fundamental properties. This compound serves as a valuable subject for researchers investigating the interplay between alkali metal cations and transition metal fluoride frameworks.
Key Properties
Cross-validated computational properties for KNbF6, 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 KNbF6. 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 KNbF6, 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. |
|---|---|---|---|---|---|
| — | — | 5.51 | 0.0000 | -3.373 | — |
| P42/mcm (No. 132) | tetragonal | 5.13 | 0.0000 | -6.254 | 3.06 |
| P42/mcm (No. 132) | tetragonal | 5.09 | 0.0000 | -3.208 | — |
| P-4c2 (No. 116) | tetragonal | 5.12 | 0.0014 | -6.252 | 2.83 |
| P42/mcm (No. 132) | tetragonal | 5.11 | 0.0091 | -3.199 | — |
| — | — | 5.36 | 0.0190 | -3.354 | — |
| — | — | 5.32 | 0.0381 | -3.335 | — |
| — | — | 5.21 | 0.0444 | -3.329 | — |
| — | — | 4.93 | 0.0704 | -3.303 | — |
| — | — | 5.40 | 0.1248 | -3.248 | — |
| P-4c2 (No. 116) | tetragonal | — | — | — | 3.03 |
| P-4c2 (No. 116) | tetragonal | — | — | — | 2.96 |
Applications
Where KNbF6 is used.
Frequently Asked Questions
Common questions about KNbF6, answered from cross-validated data.
What is KNbF6?
KNbF6 is a stable, insulating fluoride compound composed of potassium, niobium, and fluorine.
What is KNbF6 used for?
What is the band gap of KNbF6?
Is KNbF6 a metal, semiconductor, or insulator?
Is KNbF6 thermodynamically stable?
What is the crystal structure of KNbF6?
What is the density of KNbF6?
How many polymorphs of KNbF6 are known?
What elements does KNbF6 contain?
Where does the data for KNbF6 come from?
How It Compares
As a distinct inorganic fluoride, KNbF6 occupies a unique position in materials research, serving as a stable model system for understanding the coordination chemistry of niobium in fluoride environments.
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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (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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