Safer Pyrotechnic Obscurants Based on Phosphorus(V) Nitride

• Published in: Angewandte Chemie International Edition Vol. 55; no. 49; pp. 15439 - 15442
• Main Authors: Koch, Ernst-Christian, Cudziło, Stanisław
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 05.12.2016; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Fireworks; obscurants; Phosphorus; phosphorus(V) nitride; pyrotechnics; red phosphorus; safety; obscurants; pyrotechnics; phosphorus(V) nitride; safety; red phosphorus
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201609532

The potential of phosphorus(V) nitride, P3N5 , as a replacement for red phosphorus, PR, in pyrotechnic obscurants has been theoretically and experimentally investigated. P3N5 can be safely mixed with KNO3 and even KClO3 and KClO4 . The corresponding formulations are surprisingly insensitive to friction and only mildly impact‐sensitive. P3N5 /KNO3 pyrolants with ξ=20–80 wt % P3N5 burn 200 times faster than the corresponding mixtures based on PR and generate a dense smoke. Hence obscurants based on P3N5 /KNO3 have a figure of merit that by far exceeds that of current state‐of‐the‐art PR‐based obscurants. Furthermore, unlike PR, which slowly degrades in moist air to phosphoric acids and phosphine (PH3), P3N5 is stable under these conditions and does not produce any acids or PH3 . P3N5 is hence a safe, stable, and powerful replacement for PR for use in insensitive munitions. Taming phosphorus smoke: Phosphorus(V) nitride, P3N5, is a powerful and safe alternative to red phosphorus (PR) in pyrotechnic obscurants. Mixtures of P3N5 with nitrates and even chlorates are insensitive to friction and only mildly impact‐sensitive. The burn rate of P3N5/KNO3 is two orders of magnitude higher than that of PR/KNO3, which leads to an obscurant with previously unmatched performance.