Nitryl fluoride

Nitryl fluoride, NO₂F, is a colourless gas and strong oxidizing agent, which is used as a fluorinating agent and has been proposed as an oxidiser in rocket propellants (though never flown). It is a molecular species, not ionic, consistent with its low boiling point. The structure features planar nitrogen with a short N-F bond length of 135 pm.

Preparation

Henri Moissan and Lebeau recorded the preparation of nitryl fluoride in 1905 by the fluorination of nitrogen dioxide. This reaction is highly exothermic, which leads to contaminated products. The simplest method avoids fluorine gas but uses cobalt(III) fluoride:

The CoF₂ can be regenerated to CoF₃. Other methods have been described.

Thermodynamic properties

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.3