Nitrosyl azide

Nitrosyl azide is an inorganic compound of nitrogen and oxygen with the chemical formula N3\sN\dO. It is a highly labile nitrogen oxide with the empirical formula N4O.

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


 * Nitrosyl azide synthesis.svg

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:


 * Nitrosyl azide reaction 01.svg

Characterization of the compound with IR and Raman spectroscopy show absorption bands that agree well with calculated values for a trans-structure. 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 surpass the 205 kJ/mol activation energy barrier require to bend the azide group, which might explain why nitrosyl azide is stable enough to be isolated at low temperature.


 * Nitrosyl_azide_reaction_02.svg