Fluorine azide explained

Fluorine azide or triazadienyl fluoride is a yellow green gas composed of nitrogen and fluorine with formula .^[1] Its properties resemble those of , , and .^[2] The bond between the fluorine atom and the nitrogen is very weak, leading to this substance being very unstable and prone to explosion.^[3] Calculations show the F–N–N angle to be around 102° with a straight line of 3 nitrogen atoms.^[4]

The gas boils at –30° and melts at –139 °C.

It was first made by John F. Haller in 1942.^[5]

Reactions

Fluorine azide can be made by reacting hydrazoic acid or sodium azide, with fluorine gas.^{[6] [7]}

Fluorine azide decomposes without explosion at normal temperatures to make dinitrogen difluoride:

.^[1]

At higher temperatures such as 1000 °C fluorine azide breaks up into nitrogen monofluoride radical:^[7]

The FN itself dimerizes on cooling.

Solid or liquid can explode, releasing a large amount of energy. A thin film burns at the rate of 1.6 km/s.^[8] Due to the explosion hazard, only very small quantities of this substance should be handled at a time.

adducts can be formed with the Lewis acids boron trifluoride and arsenic pentafluoride at -196 °C. These molecules bond with the first nitrogen atom from the fluorine.^[9]

Properties

Spectroscopy

Parameter	Value	Unit
A	48131.448	MHz
B	5713.266	MHz
C	5095.276	MHz
μa	1.1
μb	0.7

Shape

Distances between atoms are F–N 0.1444 nm, FN=NN 0.1253 nm and FNN=N 0.1132 nm.^[10]

Physical

has a density of 1.3 g/cm³.^[11]

adsorbs on to solid surfaces of potassium fluoride, but not onto lithium fluoride or sodium fluoride. This property was being investigated so that could boost the energy of solid propellants.^[11]

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, n_N or n_F, n_F, π_F, n_N or σ, π and σ.^[3]

Notes and References

1. Gipstein. Edward. John F. Haller . 1966. Absorption Spectrum of Fluorine Azide. Applied Spectroscopy. 20. 6. 417–418. 0003-7028. 10.1366/000370266774386470. 1966ApSpe..20..417G. 96337253 .
2. Book: Saxena, P. B.. Chemistry of Interhalogen Compounds. 16 June 2014. 2007-01-01. Discovery Publishing House. 9788183562430. 96.
3. Rademacher. Paul. Andreas J. Bittner . Gabriele Schatte . Helge Willner . 1988. Photoelectron Spectrum and Electronic Structure of Triazadienyl Fluoride, N3F. Chemische Berichte. 121. 3. 555–557. 0009-2940. 10.1002/cber.19881210325.
4. Peters. Nancy J. S.. Leleand C. Allen. Leland C. Allen . Raymond A. Firestone . 1988. Fluorine azide and fluorine nitrate: structure and bonding. Inorganic Chemistry. 27. 4. 755–758. 0020-1669. 10.1021/ic00277a035.
5. Web site: Things I Won't Work With: Triazadienyl Fluoride.. Lowe. Derek. Derek Lowe (chemist). 21 October 2008. In the Pipeline. 15 June 2014.
6. Gholivand. Khodayar. Gabriele Schatte . Helge Willner . 1987. Properties of triazadienyl fluoride, N3F. Inorganic Chemistry. 26. 13. 2137–2140. 0020-1669. 10.1021/ic00260a025.
7. Benard. D. J.. B. K. Winker . T. A. Seder . R. H. Cohn . 1989. Production of nitrogen monofluoride (a1Δ) by dissociation of fluorine azide. The Journal of Physical Chemistry. 93. 12. 4790–4796. 0022-3654. 10.1021/j100349a022.
8. Seder. T.A.. D.J. Benard . 1991. The decomposition of condensed phase fluorine azide. Combustion and Flame. 85. 3–4. 353–362. 0010-2180. 10.1016/0010-2180(91)90139-3.
9. Schatte. G.. H. Willner . 1991. Die Wechselwirkung von N₃F mit Lewis-Säuren und HF. N₃F als möglicher Vorläufer für die Synthese von N₃+-Salzen = The interaction of N₃F with Lewis acids and HF•N₃F as possible precursor for the synthesis of N₃+ salts. Zeitschrift für Naturforschung B. 46. 4. 483–489. 10.1515/znb-1991-0410 . 97045269 . 0932-0776. de. free.
10. Christen. Dines.. H. G. Mack . G. Schatte . H. Willner . 1988. Structure of triazadienyl fluoride, FN₃, by microwave, infrared, and ab initio methods. Journal of the American Chemical Society. 110. 3. 707–712. 0002-7863. 10.1021/ja00211a007.
11. Book: Brener. Nathan E.. Kestner. Neil R.. Callaway. Joseph. Theoretical Studies of Highly Energetic CBES Materials: Final Report for the Period 2 March 1987 to 31 May 1987. https://web.archive.org/web/20160303170221/http://www.dtic.mil/dtic/tr/fulltext/u2/a231340.pdf. live. March 3, 2016. 25 June 2014. December 1990. Louisiana State University, Department of Physics and Astronomy. 21–27.