Produced by the action of sulfuric acid on sodium azide: L. F. Audrieth, C. F. Gibbs, Inorg. Synth. 1, 77 (1939); using stearic acid: Günther, Meyer, Z. Elektrochem. 41, 541 (1935). Prepn of water and ether solns of hydrazoic acid: W. S. Frost et al., J. Am. Chem. Soc. 55, 3516 (1933); L. F. Audrieth, C. F. Gibbs, loc. cit.; P. W. Schenk in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 472-474. GC determn: J. M. Zehner, R.A. Simonaitis, J. Chromatogr. Sci. 14, 493 (1976). Toxicity study: Graham et al., J. Ind. Hyg. Toxicol. 30, 98 (1948). Review of toxicology: C. F. Reinhardt, M. R. Brittelli, in Patty's Industrial Hygiene and Toxicology Vol. 2A, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 1981) pp 2779-2784. Reviews: Mason in Mellor's vol. VIII, suppl. II, Nitrogen (part II), 1-15 (1967); Jones in Comprehensive Inorganic Chemistry vol. 2, J. C. Bailar Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 276-293.