Nitryl fluoride
Encyclopedia
Nitryl fluoride, NO2F, is a colourless gas and strong oxidizing agent, which is used as an oxidizer in rocket propellants and as a fluorinating agent. 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.
and Lebeau were documented 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. Other method have been described.
Preparation
Henri MoissanHenri Moissan
Ferdinand Frederick Henri Moissan was a French chemist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds.-Biography:...
and Lebeau were documented the preparation of nitryl fluoride in 1905 by the fluorination of nitrogen dioxide
Nitrogen dioxide
Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...
. This reaction is highly exothermic, which leads to contaminated products. The simplest method avoids fluorine gas but uses cobalt(III) fluoride
Cobalt(III) fluoride
Cobalt fluoride is the inorganic compound with the formula CoF3. This highly reactive, hygroscopic brown solid is used to synthesize organofluorine compounds...
:
- NO2 + CoF3 → NO2F + CoF2
The CoF2 can be regenerated. Other method 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- The equilibrium of the unimolecular decomposition of FNO2 lies on the side of the reactants by at least six orders of magnitude at 500 degrees Kelvin, and two orders of magnitude at 1000 degrees Kelvin.
- The homogeneous thermal decomposition cannot be studied at temperatures below 1200 degrees Kelvin.
- The equilibrium shifts towards the reactants with increasing temperature.
- 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.