Safer Pyrotechnic Obscurants Based on Phosphorus(V) Nitride.

The potential of phosphorus(V) nitride, P N  , as a replacement for red phosphorus, P , in pyrotechnic obscurants has been theoretically and experimentally investigated. P N can be safely mixed with KNO and even KClO and KClO  . The corresponding formulations are surprisingly insensitive to friction and only mildly impact-sensitive. P N  /KNO pyrolants with ξ=20-80 wt % P N burn 200 times faster than the corresponding mixtures based on P and generate a dense smoke. Hence obscurants based on P N  /KNO have a figure of merit that by far exceeds that of current state-of-the-art P -based obscurants. Furthermore, unlike P , which slowly degrades in moist air to phosphoric acids and phosphine (PH ), P N is stable under these conditions and does not produce any acids or PH  . P N is hence a safe, stable, and powerful replacement for P for use in insensitive munitions.