3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||61.019 g/mol|
|Melting point||−139 °C (−218 °F; 134 K)|
|Boiling point||−30 °C (−22 °F; 243 K)|
|Occupational safety and health (OHS/OSH):|
|Extremely sensitive explosive|
|NFPA 704 (fire diamond)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Fluorine azide or triazadienyl fluoride is a yellow green gas composed of nitrogen and fluorine with formula FN3. Its properties resemble those of ClN3, BrN3, and IN3. The bond between the fluorine atom and the nitrogen is very weak, leading to this substance being very unstable and prone to explosion. Calculations show the F–N–N angle to be around 102° with a straight line of 3 nitrogen atoms.
The gas boils at –30° and melts at –139 °C.
It was first made by John F. Haller in 1942.
Fluorine azide can be made by reacting hydrazoic acid or sodium azide, with fluorine gas.
Fluorine azide decomposes without explosion at normal temperatures to make dinitrogen difluoride:
At higher temperatures such as 1000 °C fluorine azide breaks up into nitrogen monofluoride radical:
The FN itself dimerizes on cooling.
Solid or liquid FN3 explodes, releasing much heat. A thin film burns at the rate of 1.6 km/s. Because the explosion hazard is great only very small quantities of this substance should be handled at a time. A 0.02 g limit is recommended for experiments.
FN3 adducts can be formed with the Lewis acids boron trifluoride (BF3) and arsenic pentafluoride (AsF5) at -196 °C. These molecules bond with the Nα atom.
Distances between atoms are F–N 0.1444 nm, FN=NN 0.1253 nm and FNN=N 0.1132 nm.
FN3 has a density of 1.3 g/cm3.
FN3 adsorbs on to solid surfaces of potassium fluoride, but not onto lithium fluoride or sodium fluoride. This property was being investigated so that FN3 could boost the energy of solid propellants.
The ultraviolet photoelectric spectrum shows ionisation peaks at 11.01, 13,72, 15.6, 15.9, 16.67, 18.2, and 19.7 eV. Respectively these are assigned to the orbitals: π, nN or nF, nF, πF, nN or σ, π and σ.