Nitryl Fluoride, NO₂F

This compound is obtained by the action of nitric oxide on fluorine at the temperature of liquid air:

4NO + F₂ = 2NO₂F + N₂.

At ordinary temperatures nitryl fluoride is a colourless, pungent- smelling gas, which attacks the mucous membrane. The liquid boils at - 63-5° C., and solidifies at -139° C. to a colourless solid. The vapour density is 2.24 (compared with air=1), which is almost identical with that required by the formula NO₂F (2.26).

The gas is very reactive, and attacks many metals and non-metals, such as arsenic, antimony, aluminium, iron, mercury, alkali and alkaline earth metals, phosphorus, boron, and silicon. It has no action on hydrogen, sulphur, or carbon. Water decomposes nitryl fluoride with the quantitative formation of nitric and hydrofluoric acids:

NO₂F + H₂O = HNO₃ + HF.