Potassium azide

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Potassium azide
K+.svg
Azid-Ion.svg
KN3viewCropped.tif
Names
IUPAC name
Potassium azide
Identifiers
3D model (JSmol)
ECHA InfoCard 100.039.997 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/K.N3/c;1-3-2/q+1;-1
    Key: TZLVRPLSVNESQC-UHFFFAOYSA-N
  • [N-]=[N+]=[N-].[K+]
Properties
KN3
Molar mass 81.1184 g/mol
AppearanceColorless crystals [1]
Density 2.038 g/cm3
[1]
Melting point 350 °C (662 °F; 623 K) (in vacuum) [1]
Boiling point decomposes
41.4 g/100 mL (0 °C)
50.8 g/100 mL (20 °C)
105.7 g/100 mL (100 °C)
Solubility 0.1375 g/100 g in ethanol (16°C) [2]
insoluble in ether
Thermochemistry
-1.7 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Very Toxic, explosive if strongly heated
NFPA 704 (fire diamond)
NFPA 704.svgHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 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. gasolineInstability 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 peroxideSpecial hazards (white): no code
4
3
3
Lethal dose or concentration (LD, LC):
27 mg/kg (oral, rat) [3]
Related compounds
Other cations
Sodium azide, copper(II) azide, lead(II) azide, silver azide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.

Contents

It has been found to act as a nitrification inhibitor in soil. [4]

Structure

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]

Coordination sphere of azide in K,Rb,Cs,TlN3 AzideCoordinationCropped.tif
Coordination sphere of azide in K,Rb,Cs,TlN3

Synthesis and reactions

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

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]

Related Research Articles

<span class="mw-page-title-main">Alkali metal</span> Group of highly reactive chemical elements

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

<span class="mw-page-title-main">Caesium</span> Chemical element, symbol Cs and atomic number 55

Caesium is a chemical element; it has symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of 28.5 °C, which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at −116 °C (−177 °F). It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors. It has the largest atomic radius of all elements whose radii have been measured or calculated, at about 260 picometers.

In chemistry, azide is a linear, polyatomic anion with the formula N−3 and structure N=N+=N. It is the conjugate base of hydrazoic acid HN3. Organic azides are organic compounds with the formula RN3, containing the azide functional group. The dominant application of azides is as a propellant in air bags.

Cuprates are a class of compounds that contain copper (Cu) atom(s) in an anion. They can be broadly categorized into two main types:

<span class="mw-page-title-main">Sodium azide</span> Chemical compound

Sodium azide is an inorganic compound with the formula NaN3. This colorless salt is the gas-forming component in some car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance, is highly soluble in water, and is acutely poisonous.

<span class="mw-page-title-main">Hydrazoic acid</span> Unstable and toxic chemical compound

Hydrazoic acid, also known as hydrogen azide, azic acid or azoimide, is a compound with the chemical formula HN3. It is a colorless, volatile, and explosive liquid at room temperature and pressure. It is a compound of nitrogen and hydrogen, and is therefore a pnictogen hydride. The oxidation state of the nitrogen atoms in hydrazoic acid is fractional and is -1/3. It was first isolated in 1890 by Theodor Curtius. The acid has few applications, but its conjugate base, the azide ion, is useful in specialized processes.

Sodium oxide is a chemical compound with the formula Na2O. It is used in ceramics and glasses. It is a white solid but the compound is rarely encountered. Instead "sodium oxide" is used to describe components of various materials such as glasses and fertilizers which contain oxides that include sodium and other elements.

<span class="mw-page-title-main">Potassium cyanate</span> Chemical compound

Potassium cyanate is an inorganic compound with the formula KOCN. It is a colourless solid. It is used to prepare many other compounds including useful herbicide. Worldwide production of the potassium and sodium salts was 20,000 tons in 2006.

<span class="mw-page-title-main">Silver azide</span> Chemical compound

Silver azide is the chemical compound with the formula AgN3. It is a silver(I) salt of hydrazoic acid. It forms a colorless crystals. Like most azides, it is a primary explosive.

The chemical element nitrogen is one of the most abundant elements in the universe and can form many compounds. It can take several oxidation states; but the most common oxidation states are -3 and +3. Nitrogen can form nitride and nitrate ions. It also forms a part of nitric acid and nitrate salts. Nitrogen compounds also have an important role in organic chemistry, as nitrogen is part of proteins, amino acids and adenosine triphosphate.

<span class="mw-page-title-main">Hexazine</span> Chemical compound

Hexazine is a hypothetical allotrope of nitrogen composed of 6 nitrogen atoms arranged in a ring-like structure analogous to that of benzene. As a neutrally charged species, it would be the final member of the azabenzene (azine) series, in which all of the methine groups of the benzene molecule have been replaced with nitrogen atoms. The two last members of this series, hexazine and pentazine, have not been observed, although all other members of the azine series have.

<span class="mw-page-title-main">Barium azide</span> Chemical compound

Barium azide is an inorganic azide with the formula Ba(N3)2. It is a barium salt of hydrazoic acid. Like most azides, it is explosive. It is less sensitive to mechanical shock than lead azide.

<span class="mw-page-title-main">Silicon tetraazide</span> Chemical compound

Silicon tetraazide is a thermally unstable binary compound of silicon and nitrogen with a nitrogen content of 85.7%. This high-energy compound combusts spontaneously and can only be studied in a solution. A further coordination to a six-fold coordinated structure such as a hexaazidosilicate ion [Si(N3)6]2− or as an adduct with bicationic ligands Si(N3)4·L2 will result in relatively stable, crystalline solids that can be handled at room temperature.

<span class="mw-page-title-main">Fluorine azide</span> Chemical compound

Fluorine azide or triazadienyl fluoride is a yellow green gas composed of nitrogen and fluorine with formula FN3. Its properties resemble those of ClN3, BrN3, and IN3. The bond between the fluorine atom and the nitrogen is very weak, leading to this substance being very unstable and prone to explosion. Calculations show the F–N–N angle to be around 102° with a straight line of 3 nitrogen atoms.

<span class="mw-page-title-main">Rubidium azide</span> Chemical compound

Rubidium azide is an inorganic compound with the formula RbN3. It is the rubidium salt of the hydrazoic acid HN3. Like most azides, it is explosive.

<span class="mw-page-title-main">Fluorocarbonate</span> Class of chemical compounds

A carbonate fluoride, fluoride carbonate, fluorocarbonate or fluocarbonate is a double salt containing both carbonate and fluoride. The salts are usually insoluble in water, and can have more than one kind of metal cation to make more complex compounds. Rare-earth fluorocarbonates are particularly important as ore minerals for the light rare-earth elements lanthanum, cerium and neodymium. Bastnäsite is the most important source of these elements. Other artificial compounds are under investigation as non-linear optical materials and for transparency in the ultraviolet, with effects over a dozen times greater than Potassium dideuterium phosphate.

<span class="mw-page-title-main">Caesium azide</span> Chemical compound

Caesium azide or cesium azide is an inorganic compound of caesium and nitrogen. It is a salt of azide with the formula CsN3.

<span class="mw-page-title-main">Boron triazide</span> Chemical compound

Boron triazide, also known as triazidoborane, is a thermally unstable compound of boron and nitrogen with a nitrogen content of 92.1 %. Formally, it is the triazido derivative of borane and is a covalent inorganic azide. The high-energy compound, which has the propensity to undergo spontaneous explosive decomposition, was first described in 1954 by Egon Wiberg and Horst Michaud of the University of Munich.

<span class="mw-page-title-main">Pentazenium tetraazidoborate</span> Chemical compound

Pentazenium tetraazidoborate is an extremely unstable chemical compound with the formula N5[B(N3)4]. It is a white solid that violently explodes at room temperature. This compound has a 95.7% nitrogen content which is the second highest known of a chemical compound, exceeding even that of ammonium azide (93.3%) and 1-diazidocarbamoyl-5-azidotetrazole (89.1%), being surpassed only by hydrazoic acid (97.7%).

References

  1. 1 2 3 Dale L. Perry; Sidney L. Phillips (1995). Handbook of inorganic compounds. CRC Press. p. 301. ISBN   0-8493-8671-3.
  2. 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.
  3. "Substance Name: Potassium azide". chem.sis.nlm.nih.gov. Archived from the original on 2014-08-12. Retrieved 2014-08-11.
  4. 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.
  5. 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.
  6. 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
  7. 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.
  8. 1 2 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
  9. 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.
  10. E. Dönges "Alkali Metals" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 475
  11. 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.
  12. 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 (2023-03-06). "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.