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| Identifiers | |||
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3D model (JSmol) | |||
| ChemSpider |
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| ECHA InfoCard | 100.030.007 | ||
| EC Number |
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| UNII | |||
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| Properties | |||
| FNO2 | |||
| Molar mass | 65.003 g·mol−1 | ||
| Melting point | −166 °C (−267 °F; 107 K) | ||
| Boiling point | −72 °C (−98 °F; 201 K) | ||
| Related compounds | |||
Otheranions | nitryl chloride,nitryl bromide | ||
Othercations | nitrosyl fluoride,sulfuryl fluoride | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Nitryl fluoride, NO2F, is a colourless gas and strong oxidizing agent, which is used as a fluorinating agent[1] and has been proposed as an oxidiser inrocket propellants (though never flown).
It is a molecular species, not ionic, consistent with its lowboiling point. The structure features planar nitrogen with a short N-F bond length of 135pm.[2]
Henri Moissan andPaul Lebeau recorded the preparation of nitryl fluoride in 1905 by thefluorination ofnitrogen dioxide. This reaction is highly exothermic, which leads to contaminated products. The simplest method avoids fluorine gas but usescobalt(III) fluoride:[3]
The CoF2 can be regenerated to CoF3. Other methods have been described.[4]
The thermodynamic properties of this gas were determined by IR and Raman spectroscopy. The standard heat of formation of FNO2 is -19 ± 2 kcal/mol, but the compound becomes increasingly unstable at higher temperature.[5] The homogeneous thermal decomposition cannot be studied at temperatures below 1200 kelvin, because the notional unimolecular decomposition equilibrium lies on the adduct side by at least six orders of magnitude at 500 kelvin, and two orders of magnitude at 1000 kelvin.[5]
The dissociation energy of 46.0 kcal of the N-F bond in nitryl fluoride is about 18 kcal less than the normal N-F single bond energy. This can be attributed to the “reorganization energy” of the NO2 radical; that is, the NO2 radical in FNO2 is less stable than the free NO2 molecule. Qualitatively speaking, the odd electron “used up” in the N-F bond forms a resonating three-electron bond in free NO2, thus stabilizing the molecule with a gain of 18 kcal.[5]
Nitryl fluoride can be used to prepare organicnitro compounds andnitrate esters.
