Potassium azide

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Potassium azide
K+.svg Azid-Ion.svg
CAS number 20762-60-1 YesY
PubChem 10290740
Jmol-3D images Image 1
Molecular formula KN
Molar mass 81.1184 g/mol
Appearance Colorless crystals[1]
Density 2.038 g/cm3
Melting point 350 °C (662 °F; 623 K) (in vacuum)[1]
Boiling point decomposes
Solubility in water 41.4 g/100 mL (0 °C)
50.8 g/100 mL (20 °C)
105.7 g/100 mL (100 °C)
Solubility soluble in ethanol
insoluble in ether
Std enthalpy of
-1.7 kJ/mol
Main hazards Very Toxic, explosive if strongly heated
NFPA 704
Flammability code 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) Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 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., fluorine Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 27 mg/kg (oral, rat)[2]
Related compounds
Other cations Sodium azide, copper(II) azide, lead(II) azide, silver azide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Potassium azide is the chemical compound having the formula KN
. It is the potassium salt of hydrazoic acid, and crystallizes in a tetragonal structure.[3] Upon heating or irradiation with ultraviolet light, it decomposes into potassium metal and nitrogen gas.[4][5] Unlike heavy-metal azides, it is not sensitive to shock, but may explode if heated rapidly.[6]

It has been found to act as a nitrification inhibitor in soil.[7]


Potassium azide can be prepared by the reaction of hydrazoic acid and potassium hydroxide[citation needed].

Health hazards[edit]

Like sodium azide, potassium azide is a very toxic chemical due to inhibition of cytochrome c oxidase[citation needed]. It may be fatal if ingested, in contact with skin or if inhaled.


  1. ^ a b c Dale L. Perry; Sidney L. Phillips (1995). Handbook of inorganic compounds. CRC Press. p. 301. ISBN 0-8493-8671-3. 
  2. ^ http://chem.sis.nlm.nih.gov/chemidplus/rn/20762-60-1
  3. ^ Khilji, M. Y.; Sherman, W. F.; Wilkinson, G. R. (1982). "Variable temperature and pressure Raman spectra of potassium azide KN
    ". Journal of Raman Spectroscopy 12 (3): 300–303. Bibcode:1982JRSp...12..300K. doi:10.1002/jrs.1250120319.
  4. ^ 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. 
  5. ^ Pradyot Patnaik (2003). Handbook of inorganic chemicals. McGraw-Hill Professional. p. 734. ISBN 0-07-049439-8. 
  6. ^ Pradyot Patnaik (2007). A comprehensive guide to the hazardous properties of chemical substances (3rd ed.). Wiley-Interscience. p. 615. ISBN 0-471-71458-5. 
  7. ^ T. D. Hughes; L. F. Welch (1970). "Potassium Azide as a Nitrification Inhibitor". Agronomy Journal (American Society of Agronomy) 62: 595–599. doi:10.2134/agronj1970.00021962006200050013x.