Ammonium azide is the chemical compound with the formula [NH4]N3, being the salt of ammonia and hydrazoic acid. Like other inorganic azides, this colourless crystalline salt is a powerful explosive, although it has a remarkably low sensitivity. [NH4]N3 is physiologically active and inhalation of small amounts causes headaches and palpitations. It was first obtained by Theodor Curtius in 1890, along with other azides.
Structure Ammonium azide is ionic, meaning it is a salt consisting of ammonium cations [NH4]+ and azide anions N−3, therefore its formula is [NH4]+[N3]−. It is a structural isomer of tetrazene. Ammonium azide contains about 93% nitrogen by mass.
Preparation There are two major methods of producing ammonium azide. Small quantities (grams) of ammonium azide are produced by bubbling ammonia gas through a solution of hydrazoic acid in diethyl ether:
NH3 + HN3 → [NH4]N3 Larger quantities are produced by the reaction of sodium azide and ammonium chloride in dimethylformamide at 100 °C.
References
Yakovleva, G. S.; Kurbangalina, R. Kh.; Stesik, L. N. (1977). "Detonation properties of ammonium azide". Combustion, Explosion, and Shock Waves. 13 (3): 405. Bibcode:1977CESW...13..405Y. doi:10.1007/BF00740326. S2CID 93777687. Salim de Amorim, Helio; do Amaral, M. R.; Pattison P.; Ludka I. P.; Mendes, J. C. (2002). "Ammonium azide: A Commented Example of an Ab Initio Structure (Re-)Determination From X-Ray Diffraction" (PDF). Revista de la Sociedad Química de Mexico. 45 (4): 313–319. Archived (PDF) from the original on 2012-04-06. Curtius, Th. (1890). "Ueber Stickstoffwasserstoffsäure (Azoimid) N3H". Berichte der Deutschen Chemischen Gesellschaft. 23 (2): 3023–3033. doi:10.1002/cber.189002302232.
Further reading Schmidt, Eckart W. (2022). "Ammonium Azide". Azides and Azido Compounds. Encyclopedia of Liquid Fuels. De Gruyter. pp. 893–900. doi:10.1515/9783110750287-011. ISBN 978-3-11-075028-7.