Editing Azide (section)

== Applications ==
In 2005, about 251 tons of azide-containing compounds were annually produced in the world, the main product being sodium azide.<ref name=Ullmann>{{cite book |first1=Horst H. |last1=Jobelius |first2=Hans-Dieter |last2=Scharff |chapter=Hydrazoic Acid and Azides |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2005 |publisher=Wiley-VCH |location=Weinheim |doi=10.1002/14356007.a13_193|isbn=3527306730 }}</ref>

=== Primary explosives and propellants===
[[Sodium azide]] {{chem2|NaN3}} is the propellant in automobile [[airbag]]s. It decomposes on heating to give nitrogen gas, which is used to quickly expand the air bag:<ref name=Ullmann/>

:{{chem2|2 NaN3 → 2 Na + 3 N2}}

Heavy metal azides, such as [[lead azide]], {{chem2|Pb(N3)2}}, are shock-sensitive [[detonator]]s which violently decompose to the corresponding metal and nitrogen, for example:<ref>{{cite book |last1=Shriver |last2=Atkins |title=Inorganic Chemistry |edition=5th |publisher= W. H. Freeman and Company |location=New York |page=382}}</ref>

:{{chem2|Pb(N3)2 → Pb + 3 N2}}

[[Silver azide]] {{chem2|AgN3}} and [[barium azide]] {{chem2|Ba(N3)2}} are used similarly.

Some organic azides are potential [[Rocket propellant|rocket propellants]], an example being [[2-Dimethylaminoethylazide|2-dimethylaminoethylazide]] (DMAZ) {{chem2|(CH3)2NCH2CH2N3}}.

=== Microbial inhibitor and undesirable side effects ===
Sodium azide is commonly used in the laboratory as a [[bacteriostatic]] agent to avoid microbial proliferation in [[abiotic]] control experiments in which it is important to avoid microbial activity. However, it has the disadvantage to be prone to trigger unexpected and undesirable side reactions that can jeopardize the experimental results. Indeed, the azide anion is a [[nucleophile]] and a [[Redox|redox-active]] species. Being prone to [[disproportionation]], it can behave both as an [[oxidizing agent| oxidizing]] and as a [[reducing agent]]. Therefore, it is susceptible to interfere in an unpredictable way with many substances.<ref name="Rozycki1981">{{cite journal | last1=Rozycki | first1=Michael | last2=Bartha | first2=Richard | date=1981 | title=Problems associated with the use of azide as an inhibitor of microbial activity in soil | journal=Applied and Environmental Microbiology | volume=41 | issue=3 | pages=833–836 | issn=0099-2240 | pmid=16345743 | pmc=243784 | doi=10.1128/aem.41.3.833-836.1981}}</ref><ref name="Lindner1984">{{cite journal | last1=Lindner | first1=Pinhas | last2=Shomer | first2=Ilan | year=1984 | title=Interference of azide in assays of carbohydrates | journal=Food Chemistry | volume=14 | issue=2 | pages=141–153 | issn=0308-8146 | doi=10.1016/0308-8146(84)90053-0}}</ref><ref name="Goel2003">{{cite journal | last1=Goel | first1=Ramesh K | last2=Cooper | first2=Adrienne T | last3=Flora | first3=Joseph R.V | date=2003-09-01 | title=Sodium azide interference in chemical and biological testing | journal=Journal of Environmental Engineering and Science | volume=2 | issue=5 | pages=407–411 | issn=1496-2551 | doi=10.1139/s03-043}}</ref> For example, the azide anion can [[Redox|oxidize]] [[pyrite]] ({{Chem2|FeS2}}) with the formation of [[thiosulfate]] ({{Chem2|S2O3(2-)}}), or [[Redox|reduce]] [[quinone]] into [[hydroquinone]].<ref name="Hendrix2019">{{cite journal | last1=Hendrix | first1=Katrien | last2=Bleyen | first2=Nele | last3=Mennecart | first3=Thierry | last4=Bruggeman | first4=Christophe | last5=Valcke | first5=Elie | title=Sodium azide used as microbial inhibitor caused unwanted by-products in anaerobic geochemical studies | journal=Applied Geochemistry | volume=107 | year=2019 | issn=0883-2927 | doi=10.1016/j.apgeochem.2019.05.014 | pages=120–130}}</ref> It can also reduce [[nitrite]] {{Chem2|NO2-}} into [[nitrous oxide]] {{Chem2|N2O}}, and {{Chem2|Fe(2+)}} into {{Chem2|Fe^{0}|}} ([[zerovalent iron]], ZVI).<ref name="Hendrix2019" /> Azide can also enhance the {{N2O}} emission in soil. A proposed explanation is the stimulation of the denitrification processes because of the azide’s role in the synthesis of denitrifying enzymes.<ref name="Aulakh1985">{{cite journal | last1=Aulakh | first1=M. S. | last2=Rennie | first2=D. A. | date=1985-02-01 | title=Azide effects upon N<sub>2</sub>O emission and transformations of N in soils | journal=Canadian Journal of Soil Science | volume=65 | issue=1 | pages=205–212 | issn=0008-4271 | doi=10.4141/cjss85-021}}</ref> Moreover, azide also affects the [[absorbance]] and [[fluorescence]] optical properties of the [[Dissolved organic carbon|dissolved organic matter]] (DOM) from [[soil]]s.<ref name="RetellettiBrogi2019">{{cite journal | last1=Retelletti Brogi | first1=Simona | last2=Derrien | first2=Morgane | last3=Hur | first3=Jin | date=2019 | title=In-depth assessment of the effect of sodium azide on the optical properties of dissolved organic matter | journal=Journal of Fluorescence | volume=29 | issue=4 | pages=877–885 | issn=1053-0509 | doi=10.1007/s10895-019-02398-w}}</ref> Many other interferences are reported in the literature for [[Biochemistry|biochemical]] and [[Biology|biological]] analyses and they should be systematically identified and first rigorously tested in the laboratory before to use azide as [[bacteriostatic|microbial inhibitor]] for a given application. 

=== Purification of molten sodium ===
Sodium azide {{Chem2|NaN3}} is used to purify metallic sodium in laboratories handling molten sodium used as a coolant for [[fast-neutron reactor]]s.<ref name="Weber1951">{{Cite journal | last1=Weber | first1=C. E. | date=July 1948 – January 1951| title=Problems in the use of molten sodium as transfer fluid. OSTI declassified document | journal=Journal of Metallurgy and Ceramics | issue= 1 – 6 | page=291 | url=https://www.osti.gov/servlets/purl/4302453#page=202}}</ref>

As hydrazoic acid, the [[Protonation|protonated]] form of the azide anion, has a very low reduction potential (''E''°<sub>red</sub> = −3.09&nbsp;V), and is even a stronger [[Reducing agent|reductant]] than lithium (''E''°<sub>red</sub> = −3.04&nbsp;V), dry solid [[sodium azide]] can be added to molten metallic sodium (''E''°<sub>red</sub> = −2.71&nbsp;V) under strict anoxic conditions (''e.g.'', in a special anaerobic glovebox with very low residual {{O2}} {{Nowrap|(< 1 ppm vol.)}} to reduce {{Chem2|Na+}} impurities still present into the sodium bath. The reaction residue is only gaseous {{chem2|N2}}.

As ''E''°<sub>ox</sub> = −''E''°<sub>red</sub>, it gives the following series of oxidation reactions when the redox couples are presented as reductants: 
*{{Chem2|2 HN3 ⇌ 3 N2(g) + 2 H+ + 2 e-}} (''E''°<sub>ox</sub> = +3.09&nbsp;V)
*{{Chem2|Li ⇌ Li+ + e-}} (''E''°<sub>ox</sub> = +3.04&nbsp;V)
*{{Chem2|Na ⇌ Na+ + e-}} (''E''°<sub>ox</sub> = +2.71&nbsp;V)

=== Click chemistry ===
{{Main article|Click chemistry|Azide-alkyne Huisgen cycloaddition}}
The azide [[functional group]] is commonly utilized in [[click chemistry]] through [[Copper#Compounds|copper(I)]]-[[Catalysis|catalyzed]] azide-[[alkyne]] [[cycloaddition]] ([[CuAAC]]) reactions, where copper(I) catalyzes the cycloaddition of an organoazide to a terminal alkyne, forming a [[triazole]].<ref>{{cite journal| journal = Proceedings of the Chemical Society of London| page = 357| year= 1961| title = Centenary Lecture – 1,3-Dipolar Cycloadditions| author = Huisgen, R. | doi = 10.1039/PS9610000357}}</ref><ref>{{cite journal |author1=H. C. Kolb |author2=M. G. Finn |author3=K. B. Sharpless | title = Click Chemistry: Diverse Chemical Function from a Few Good Reactions | year = 2001 | journal = [[Angewandte Chemie International Edition]] | volume = 40 | issue = 11 | pages = 2004–2021 | doi = 10.1002/1521-3773(20010601)40:11<2004::AID-ANIE2004>3.0.CO;2-5 | pmid=11433435| doi-access = free }}</ref><ref>{{cite journal|last=Kolb|first=H.C.|author2=Sharpless, B.K.|title=The growing impact of click chemistry on drug discovery|year=2003|volume=8|issue=24|pages=1128–1137|doi=10.1016/S1359-6446(03)02933-7|pmid=14678739|journal=Drug Discov Today|doi-access=free}}</ref>

=== Other uses ===
A very damaging and illegal usage of sodium azide is its diversion by [[Poaching|poachers]] as a substitute of [[sodium cyanide]] to poison some animal species by blocking the [[electron transport chain]] in the [[cellular respiration]] process.