Potassium azide
| Names | |
|---|---|
| IUPAC name
Potassium azide
| |
| Properties | |
| KN3 | |
| Molar mass | 81.1184 g/mol |
| Appearance | White crystalline solid |
| Odor | Odorless |
| Density | 2.038 g/cm3 |
| Melting point | 350–360 °C (662–680 °F; 623–633 K) |
| Boiling point | 360 °C (680 °F; 633 K) (decomposes) |
| 41.4 g/100 ml (0 °C) 50.8 g/100 ml (20 °C) 105.7 g/100 ml (100 °C) | |
| Solubility | Soluble in liq. ammonia, methanol Slightly soluble in ethanol, liq. SO2 Insoluble in acetone, diethyl ether, hexane |
| Solubility in benzene | 0.15 g/100 g (80 °C)[1] |
| Solubility in ethanol | 0.16 g/100 g (0 °C) 0.137 g/100 g (16 °C)[2][3][4] |
| Solubility in ethanol 80% | 1.83 g/100 g (0 °C) 5.93 g/100 g (78.4 °C)[5] |
| Vapor pressure | ~0 mmHg |
| Thermochemistry | |
| Std molar
entropy (S |
104 J·mol-1·K-1 |
| Std enthalpy of
formation (ΔfH |
-1.7 kJ/mol |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
27 mg/kg (rat, oral) |
| Related compounds | |
| Related compounds
|
Lithium azide Sodium azide Rubidium azide Caesium azide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Potassium azide is an inorganic chemical compound with the formula KN3.
Contents
Properties
Chemical
Potassium azide decomposes when heated, to potassium metal and nitrogen gas, and may explode during decomposition.
Physical
Potassium azide is a colorless solid, soluble in water. It does not appear to be hygroscopic.
Explosive
The decomposition of potassium azide is known to be explosive.[6][7] Violent decomposition only occurs above 100 °C, below this temperature there doesn't appear to be any violent decomposition.[8]
Availability
Potassium azide is sold by chemical suppliers, but due to the high toxicity of azides, it's not readily available for the amateur chemist.
Preparation
Very pure potassium azide can be produced by reacting potassium amide with nitrous oxide, at 270-280 °C, in an inert atmosphere, in rotating furnace. KOH and ammonia may be produced as byproducts. Yield of this reaction is given as ~99%.[9] An older preparation used a lower temperature range of 150-250 °C, though the yield is not given.[10][11]
Potassium azide can be prepared by heating a mixture of ammonium nitrate or potassium nitrate with potassium amide at 90 °C, in closed tube. Yield is given as 75%. If lead(II) nitrate is used instead, the yield of the reaction is 80%.[12]
More conveniently, it can be prepared by adding a solution of potassium sulfate to another solution of either barium azide or lead(II) azide. The insoluble sulfate precipitate is then filtered, and the filtered solution is gently dried to remove the water.
Can also be easily produced in high purity by neutralizing hydrazoic acid with potassium hydroxide or potassium carbonate.
Projects
- Azidation agent
- Nitrification inhibitor
- Blasting cap
Handling
Safety
Potassium azide is extremely toxic. The toxicity of azides is similar that of cyanides. There is no known antidote.
Storage
Potassium azide should be stored in spark-free containers, away from moisture or any acidic vapors.
Disposal
When disposed of, it must never be poured down the drain, as it will react to either copper or lead plumbing to yield copper azide, which is highly sensitive. Hydrolysis can also occur in aqueous solutions, at certain pH. Potassium azide must be treated with nitrous acid before being discarded. This can be easily obtained by acidifying sodium nitrite.
References
- ↑ Seidell A. Solubilities of inorganic and metal organic compounds. - 3ed., vol.1. - New York: D. Van Nostrand Company, 1940
- ↑ Cranston; Livingstone; Journal of the Chemical Society; (1926); p. 503
- ↑ Справочник химика. - Т. 2. - Л.-М.: Химия, 1964
- ↑ Химическая энциклопедия. - Т. 2. - М.: Советская энциклопедия, 1990
- ↑ Janz G.J., Tomkins R.P.T. Nonaqueous Electrolytes Handbook. - Vol. 2. - New York and London: Academic Press, 1973 pp. 41
- ↑ Mayans, Júlia; Stoumpos, Constantinos C.; Font-Bardia, Mercé; Escuer, Albert; Chemistry - A European Journal; vol. 26; nb. 49; (2020); p. 11158 - 11169
- ↑ Bloch, Susanne; Carreira, Erick M.; Hansen, Moritz E.; Kravina, Alberto G.; Pehlivanoglu, Deren; Pultar, Felix; Riniker, Sereina; Wolfrum, Susanne; Böselt, Lennard; Fróis-Martins, Ricardo; Leibundgut-Landmann, Salomé; Schäffer, Christina; Journal of the American Chemical Society; vol. 143; nb. 27; (2021); p. 10389 - 10402
- ↑ Reckeweg, Olaf; Simon, Arndt; Zeitschrift fur Naturforschung, B: Chemical Sciences; vol. 58; nb. 11; (2003); p. 1097 - 1104
- ↑ Hoth, W.; Pyl, G.; Angewandte Chemie; vol. 42; (1929); p. 890
- ↑ Dennis, L. M.; Browne, A. W.; Zeitschrift fur anorganische Chemie; vol. 40; (1904); p. 90 - 94
- ↑ Joannis, A.; Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences; vol. 118; (1894); p. 713
- ↑ Franklin, E. C.; Journal of the American Chemical Society; vol. 56; (1934); p. 586
