Crypton difluoride
| Structural formula | ||||||||||
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| General | ||||||||||
| Surname | Crypton difluoride | |||||||||
| other names |
Krypton (II) fluoride |
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| Molecular formula | KrF 2 | |||||||||
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| properties | ||||||||||
| Molar mass | 121.79 g mol −1 | |||||||||
| Physical state |
solid (only known at low temperatures) |
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| density |
3.24 g cm −3 |
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| Sublimation point |
77 ° C |
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| Thermodynamic properties | ||||||||||
| ΔH f 0 |
15 kJ / mol (gas) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||
Krypton difluoride is an unstable chemical compound made up of krypton and fluorine . It is one of the few known krypton compounds and the first compound of this noble gas to be synthesized .
Extraction and presentation
Krypton difluoride is produced at −196 ° C with the help of electrical discharges from elemental krypton and fluorine in an endothermic reaction of 60 kJ / mol . Further extraction options are UV photolysis and the bombardment of krypton / fluorine mixtures with protons. In each case, fluorine radicals are created that are able to react with krypton.
properties
Chemical properties
Krypton difluoride is unstable and decomposes within a few days at room temperature. At 77 ° C the compound sublimes with rapid decomposition. Krypton difluoride reacts explosively with water and organic compounds.
Krypton difluoride is a strong oxidizing agent , it can convert xenon into xenon hexafluoride or iodine into iodine pentafluoride . It is also a fluoride ion donor. The cation KrF + is the strongest known oxidizing agent to date, even stronger than oxygen difluoride and elemental fluorine . It is the only known substance capable of bringing gold to the +5 oxidation state:
![{\ displaystyle {\ ce {KrF + AuF6 ^ {-} -> [60-66 \, ^ {\ circ} {\ text {C}}] AuF5 {} + Kr {} + F2}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/25cf50ddfa796f30e1dfceddb7fe4e4748213700)
Molecular geometry
According to the VSEPR model , the krypton difluoride molecule has a linear structure with a bond angle (F − Kr − F) of about 180 °. In the gaseous state the bond length is 188.9 pm .
Krypton difluoride has the point group D ∞h as its molecular symmetry .
See also
Web links
Individual evidence
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Properties of the Elements and Inorganic Compounds, pp. 4-69.
- ^ A b c John F. Lehmann, Hélène PA Mercier, Gary J. Schrobilgen: The chemistry of krypton. In: Coordination Chemistry Reviews . 2002, 233/234, pp. 1-39, doi : 10.1016 / S0010-8545 (02) 00202-3 .
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
- ↑ Erwin Riedel, Christoph Janiak: Inorganic Chemistry . 9th edition. Walter de Gruyter GmbH, Berlin 2015, ISBN 978-3-11-035526-0 , p. 416 .
- ^ A b c A. F. Holleman , N. Wiberg : Inorganische Chemie . 103rd edition. Volume 1: Basics and main group elements. Walter de Gruyter, Berlin / Boston 2016, ISBN 978-3-11-049585-0 , p. 469 (Reading sample: Part A - Basics of the chemistry of hydrogen. Google book search ). (accessed via De Gruyter Online)
- ↑ James Huheey, Ellen Keiter, Richard Keiter: Inorganic Chemistry: Principles of Structure and Reactivity , 2003, Walter de Gruyter, ISBN 3-11-017903-2 .
- ↑ Hans-Jürgen Meyer, Christoph Janiak, Dietrich Gudat, Ralf Alsfasser, Erwin Riedel: Modern Inorganic Chemistry . 4th edition. Walter de Gruyter GmbH & Co. KG, Berlin 2012, ISBN 978-3-11-024900-2 , p. 119 ( limited preview in Google Book search).