KrF2
Krypton difluoride · Krypton fluoride
Krypton difluoride is a rare, thermodynamically stable noble gas compound that functions as a potent oxidizing and fluorinating agent.
About Krypton difluoride
Krypton difluoride is a notable noble gas compound that stands out for being thermodynamically stable on the convex hull. Despite the general inertness of noble gases, this material forms a distinct crystalline structure, showcasing the unique chemistry possible when krypton is forced into bonding with highly electronegative fluorine atoms.
As a semiconducting material, it is primarily recognized for its extreme chemical reactivity. It serves as a powerful fluorinating and oxidizing agent, capable of participating in reactions that few other compounds can facilitate, making it a subject of significant interest in high-energy chemical research.
Key Properties
Cross-validated computational properties for Krypton difluoride, 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 KrF2. 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 KrF2, 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 | 2.92 | 0.0000 | -1.680 | 3.70 |
| I4/mmm (No. 139) | tetragonal | 2.63 | 0.0000 | -0.124 | — |
| — | — | 2.40 | 0.0000 | -0.312 | — |
| P42/mnm (No. 136) | tetragonal | 2.79 | 0.0104 | -1.669 | 3.37 |
| P42/mnm (No. 136) | tetragonal | 2.42 | 0.0129 | -0.111 | — |
| — | — | 2.78 | 0.0333 | -0.279 | — |
| P1 (No. 1) | triclinic | — | — | — | 3.27 |
| P1 (No. 1) | triclinic | — | — | — | 2.56 |
| P1 (No. 1) | triclinic | — | — | — | 2.49 |
| P-1 (No. 2) | triclinic | — | — | — | 2.36 |
| P-1 (No. 2) | triclinic | — | — | — | 2.53 |
| P1 (No. 1) | triclinic | — | — | — | 2.78 |
Applications
Where Krypton difluoride is used.
Frequently Asked Questions
Common questions about Krypton difluoride, answered from cross-validated data.
What is KrF2?
Krypton difluoride is a rare, thermodynamically stable noble gas compound that functions as a potent oxidizing and fluorinating agent.
What is KrF2 used for?
What is the band gap of KrF2?
Is KrF2 a metal, semiconductor, or insulator?
Is KrF2 thermodynamically stable?
What is the crystal structure of KrF2?
What is the density of KrF2?
How many polymorphs of KrF2 are known?
What elements does KrF2 contain?
Where does the data for KrF2 come from?
How It Compares
As a rare example of a stable noble gas fluoride, this compound occupies a unique position in inorganic chemistry. While many noble gas compounds are highly transient or require extreme conditions to exist, this material demonstrates a surprising level of stability, setting it apart from more volatile or unstable noble gas derivatives.
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)
- 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)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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