Nitrosyl azide

Nitrosyl azide is an inorganic compound of nitrogen and oxygen with the chemical formula N₃−N=O. It is a highly labile nitrogen oxide with the empirical formula N₄O.

Nitrosyl azide

Identifiers
CAS Number	62316-46-5
3D model (JSmol)	Interactive image
ChemSpider	13917998
PubChem CID	18974641
CompTox Dashboard (EPA)	DTXSID401029641
InChI InChI=1S/N4O/c1-2-3-4-5 Y Key: LHKVDVFVJMYULK-UHFFFAOYSA-N Y
SMILES [N-]=[N+]=NN=O
Properties
Chemical formula	N3−N=O
Molar mass	72.027 g·mol−1
Appearance	Pale yellow solid below −50 °C (−58 °F). Above that temperature it decomposes.
Related compounds
Related compounds	Nitrogen monoxide Nitrous oxide Nitryl azide Oxatetrazole
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Nitrosyl azide can be synthesized via the following reaction of sodium azide and nitrosyl chloride at low temperatures:

Properties

Below −50 °C, nitrosyl azide exists as a pale yellow solid. Above this temperature, it decomposes into nitrous oxide N₂O and molecular nitrogen N₂:^[1]

Characterization of the compound with IR and Raman spectroscopy show absorption bands that agree well with calculated values for a trans-structure.^[1][2] Quantum chemical calculations show a cis-form higher in energy by 4.2 kJ/mol and an aromatic ring form (oxatetrazole N₄O) that is more stable by 205 kJ/mol. However, the cyclization to the ring form would have to exceed the 205 kJ/mol activation energy barrier required to bend the azide group, which might explain why nitrosyl azide is stable enough to be isolated at low temperature.^[1]