Potassium azide
- 20762-60-1 checkY
- J3LSB2C8SO checkY
- InChI=1S/K.N3/c;1-3-2/q+1;-1Key: TZLVRPLSVNESQC-UHFFFAOYSA-N
- [N-]=[N+]=[N-].[K+]
[1]
50.8 g/100 mL (20 °C)
105.7 g/100 mL (100 °C)
insoluble in ether
formation (ΔfH⦵298)
- Health 4: Very short exposure could cause death or major residual injury. E.g. VX gas
- Flammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasoline
- Instability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxide
- Special hazards (white): no code
Potassium azide is the inorganic compound having the formula KN3. 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.[4]
Structure
[edit ]KN3, RbN3, CsN3, and TlN3 adopt the same structures. They crystallize in a tetragonal habit.[5] The azide is bound to eight cations in an eclipsed orientation. The cations are bound to eight terminal N centers.[6]
Synthesis and reactions
[edit ]KN3 is prepared by treating potassium carbonate with hydrazoic acid, which is generated in situ.[7] In contrast, the analogous sodium azide is prepared (industrially) by the "Wislicenus process," which proceeds via the reaction sodium amide with nitrous oxide.[8]
Upon heating or upon irradiation with ultraviolet light, it decomposes into potassium metal and nitrogen gas.[9] The decomposition temperatures of the alkali metal azides are: NaN3 (275 °C), KN3 (355 °C), RbN3 (395 °C), CsN3 (390 °C).[10]
Under high pressures and high temperatures, potassium azide was found to transform into the K2N6 and K9N56 compounds, both containing hexazine rings: N2−
6 and N64-, respectively.[11] [12]
Health hazards
[edit ]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.[8]
References
[edit ]- ^ a b c Dale L. Perry; Sidney L. Phillips (1995). Handbook of inorganic compounds. CRC Press. p. 301. ISBN 0-8493-8671-3.
- ^ Jiri Hála (2004). "IUPAC-NIST Solubility Data Series. 79. Alkali and Alkaline Earth Metal Pseudohalides". J. Phys. Chem. Ref. Data. 33: 16. doi:10.1063/1.1563591.
- ^ "Substance Name: Potassium azide". chem.sis.nlm.nih.gov. Archived from the original on 2014年08月12日. Retrieved 2014年08月11日.
- ^ T. D. Hughes; L. F. Welch (1970). "Potassium Azide as a Nitrification Inhibitor". Agronomy Journal. 62 (5). American Society of Agronomy: 595–599. doi:10.2134/agronj1970.00021962006200050013x.
- ^ Khilji, M. Y.; Sherman, W. F.; Wilkinson, G. R. (1982). "Variable temperature and pressure Raman spectra of potassium azide". Journal of Raman Spectroscopy. 12 (3): 300–303. Bibcode:1982JRSp...12..300K. doi:10.1002/jrs.1250120319.
- ^ Ulrich Müller "Verfeinerung der Kristallstrukturen von KN3, RbN3, CsN3 und TIN3" Zeitschrift für anorganische und allgemeine Chemie 1972, Volume 392, 159–166. doi:10.1002/zaac.19723920207
- ^ 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.
- ^ a b Horst H. Jobelius, Hans-Dieter Scharff "Hydrazoic Acid and Azides" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a13_193
- ^ Tompkins, F. C.; Young, D. A. (1982). "The Photochemical and Thermal Formation of Colour Centres in Potassium Azide Crystals". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. 236 (1204): 10–23.
- ^ E. Dönges "Alkali Metals" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 475
- ^ Wang, Yu; Bykov, Maxim; Chepkasov, Ilya; Samtsevich, Artem; Bykova, Elena; Zhang, Xiao; Jiang, Shu-qing; Greenberg, Eran; Chariton, Stella; Prakapenka, Vitali B.; Oganov, Artem R.; Goncharov, Alexander F. (21 April 2022). "Stabilization of hexazine rings in potassium polynitride at high pressure". Nature Chemistry. 14 (7): 794–800. arXiv:2010.15995 . Bibcode:2022NatCh..14..794W. doi:10.1038/s41557-022-00925-0. PMID 35449217. S2CID 226222305.
- ^ Laniel, Dominique; Trybel, Florian; Yin, Yuqing; Fedotenko, Timofey; Khandarkhaeva, Saiana; Aslandukov, Andrey; Aprilis, Georgios; Abrikosov, Alexei I.; Bin Masood, Talha; Giacobbe, Carlotta; Bright, Eleanor Lawrence; Glazyrin, Konstantin; Hanfland, Michael; Wright, Jonathan; Hotz, Ingrid (2023年03月06日). "Aromatic hexazine [N6]4− anion featured in the complex structure of the high-pressure potassium nitrogen compound K9N56". Nature Chemistry. 15 (5): 641–646. Bibcode:2023NatCh..15..641L. doi:10.1038/s41557-023-01148-7. ISSN 1755-4330. PMID 36879075. S2CID 257377020.