Krypton tetrafluoride

Krypton(IV) fluoride is a hypothetical inorganic chemical compound of krypton and fluorine with the chemical formula KrF₄. At one time researchers thought they had synthesized it, but the claim was discredited.^[1] The compound is predicted to be difficult to make and unstable if made.^[2] However, it is predicted to become stable at pressures greater than 15 GPa.^[3] Theoretical analysis indicates KrF₄ would have an approximately square planar molecular geometry.^[2]

Krypton tetrafluoride

Identifiers
CAS Number	13709-53-0
3D model (JSmol)	Interactive image
CompTox Dashboard (EPA)	DTXSID901304941
InChI InChI=1S/F4Kr/c1-5(2,3)4 Key: PLAFPZRFEDSAJL-UHFFFAOYSA-N
SMILES [Kr](F)(F)(F)F
Properties
Chemical formula	F4Kr
Molar mass	159.792 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

The claimed synthesis was by passing electric discharge through krypton-fluorine mixture:^[4]

Kr + 2F₂ → KrF₄

Physical properties

The claimed compound formed white crystalline solid.^[5] Thermally, it is less stable than XeF₄.^[6]

References

1. O'Donnell, T. A. (8 June 2017). The Chemistry of Fluorine: Comprehensive Inorganic Chemistry. Elsevier. p. 1026. ISBN 978-1-4831-4642-3. Retrieved 28 March 2023.
2. Dixon, David A.; Wang, Tsang-Hsiu; Grant, Daniel J.; Peterson, Kirk A.; Christe, Karl O.; Schrobilgen, Gary J. (2007). "Heats of Formation of Krypton Fluorides and Stability Predictions for KrF₄ and KrF₆ from High Level Electronic Structure Calculations". Inorg. Chem. 46 (23): 10016–10021. doi:10.1021/ic701313h. PMID 17941630.
3. Kurzydłowski, Dominik; Sołtysiak, Magdalena; Dżoleva, Aleksandra; Zaleski-Ejgierd, Patryk (2017-10-28). "High-Pressure Reactivity of Kr and F2—Stabilization of Krypton in the +4 Oxidation State". Crystals. 7 (11): 329. doi:10.3390/cryst7110329. ISSN 2073-4352.
4. Advanced Inorganic Chemistry Vol-1. Krishna Prakashan Media. p. 846. ISBN 978-81-87224-03-7. Retrieved 28 March 2023.
5. Cotton, F. Albert (1964). Progress in Inorganic Chemistry, Volume 6. John Wiley & Sons. p. 260. ISBN 978-0-470-16657-4. Retrieved 28 March 2023.
6. Grosse, A. V.; Kirshenbaum, A. D.; Streng, A. G.; Streng, L. V. (15 March 1963). "Krypton Tetrafluoride: Preparation and Some Properties". Science. 139 (3559): 1047–1048. Bibcode:1963Sci...139.1047G. doi:10.1126/science.139.3559.1047. PMID 17812982. Retrieved 28 March 2023.