Cyclo‐N₉⁻: a Novel 5/6 Fused Polynitrogen Anion for High Energy Density Materials (Adv. Sci. 19/2025)

Polynitrogen Anion In article number 2414394, Yuangang Xu, Ming Lu, and co-workers present a novel 5/6 fused polynitrogen anion, cyclo-N9−, following the cyclo-pentazolate anion. Four ionic systems derived from this framework exhibit exceptional energy density and detonation performance, surpassing even CL-20, making them highly promising candidate energetic materials with significant research value. This research provides valuable theoretical insights into the advancement of polynitrogen species synthesis.