Nitryl fluoride, NO
2F, is a colourless gas and strong oxidizing agent, which is used as a fluorinating agent and has been proposed as an oxidiser in
rocket propellant
Rocket propellant is the reaction mass of a rocket. This reaction mass is ejected at the highest achievable velocity from a rocket engine to produce thrust. The energy required can either come from the propellants themselves, as with a chemic ...
s (though never flown).
It is a molecular species, not ionic, consistent with its low
boiling point
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor.
The boiling point of a liquid varies depending upon the surrounding env ...
. The structure features planar nitrogen with a short N-F bond length of 135
pm.
Preparation
Henri Moissan
Ferdinand Frédéric Henri Moissan (28 September 1852 – 20 February 1907) was a French chemist and pharmacist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds. Moissan was one of the original mem ...
and
Paul Lebeau
Paul Marie Alfred Lebeau (19 December 1868 – 18 November 1959) was a French chemist. He studied at the elite École supérieure de physique et de chimie industrielles de la ville de Paris (ESPCI). Together with his doctoral advisor Henri Mo ...
recorded the preparation of nitryl fluoride in 1905 by the
fluorination
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers ...
of
nitrogen dioxide
Nitrogen dioxide is a 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 for use primarily in the productio ...
. This reaction is highly exothermic, which leads to contaminated products. The simplest method avoids fluorine gas but uses
cobalt(III) fluoride:
:NO
2 + CoF
3 → NO
2F + CoF
2
The CoF
2 can be regenerated to CoF
3. 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 FNO
2 is -19 ± 2 kcal/mol.3
*The equilibrium of the unimolecular decomposition of FNO
2 lies on the side of the reactants by at least six orders of magnitude at 500 kelvin, and two orders of magnitude at 1000 kelvin.
*The homogeneous thermal decomposition cannot be studied at temperatures below 1200 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 NO
2 radical; that is, the NO
2 radical in FNO
2 is less stable than the free NO
2 molecule. Qualitatively speaking, the odd electron “used up” in the N-F bond forms a resonating three-electron bond in free NO
2, thus stabilizing the molecule with a gain of 18 kcal.
Reactions
Nitryl fluoride can be used to prepare organic
nitro compound
In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups (). The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally. The nitr ...
s and
nitrate ester
In organic chemistry, a nitrate ester is an organic functional group with the formula , where R stands for any organic residue. They are the esters of nitric acid and alcohols. A well-known example is nitroglycerin, which is not a ''nitro'' com ...
s.
See also
*
Nitryl
Nitryl is the nitrogen dioxide (NO2) moiety when it occurs in a larger compound as a univalent fragment. Examples include nitryl fluoride (NO2F) and nitryl chloride (NO2Cl).
Like nitrogen dioxide, the nitryl moiety contains a nitrogen atom with ...
References
External links
WebBook page for NO2F
{{fluorine compounds
Oxyfluorides
Fluorinating agents
Nitrogen(V) compounds
Nitrogen oxohalides
Substances discovered in the 1900s