The simplest all-nitrogen ring: Photolytically filling the cyclic-N3 well.

We report evidence that cyclic-N₃ is exclusively produced in the 157-nm photolysis of ClN₃. Photoproduct translational energy measurements reveal a single-peaked distribution for an N₃-formation channel with maximum and minimum translational energies matching the theoretically predicted minimum and maximum binding energies of cyclic-N₃, respectively. The absence of linear-N₃ greatly simplifies the data analysis. The zero-Kelvin heat of formation of cyclic-N₃ is derived experimentally (142±3.5 kcal/mol) and is in excellent agreement with the best existing determinations from other studies. [ABSTRACT FROM AUTHOR]