Potassium azide is the inorganic compound having the formula . It is a white, water-soluble salt. It is used as a reagent in the laboratory.
It has been found to act as a nitrification inhibitor in soil.
Structure , , , and adopt the same structures. They crystallize in a tetragonal habit. The azide is bound to eight cations in an eclipsed orientation. The cations are bound to eight terminal N centers.Ulrich Müller "Verfeinerung der Kristallstrukturen von KN3, RbN3, CsN3 und TIN3" Zeitschrift für anorganische und allgemeine Chemie 1972, Volume 392, 159–166.
Synthesis and reactions is prepared by treating potassium carbonate with hydrazoic acid, which is generated in situ.P. W. Schenk "Alkali Azides from Carbonates" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 475. In contrast, the analogous sodium azide is prepared (industrially) by the "Wislicenus process," which proceeds via the reaction sodium amide with nitrous oxide.Horst H. Jobelius, Hans-Dieter Scharff "Hydrazoic Acid and Azides" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim.
Upon heating or upon irradiation with ultraviolet light, it decomposes into potassium metal and nitrogen gas. The decomposition temperatures of the alkali metal azides are: (275 °C), (355 °C), (395 °C), (390 °C).E. Dönges "Alkali Metals" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 475
Under high pressures and high temperatures, potassium azide was found to transform into the K2N6 and K9N56 compounds, both containing hexazine rings: N and N64-, respectively.
Health hazards Like sodium azide, potassium azide is very toxic. The threshold limit value of the related sodium azide is 0.07 ppm. The toxicity of azides arise from their ability to inhibit cytochrome c oxidase.
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