chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, proper ...

, azide is a

linear Linearity is the property of a mathematical relationship ('' function'') that can be graphically represented as a straight line. Linearity is closely related to '' proportionality''. Examples in physics include rectilinear motion, the linear ...

polyatomic anion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zero. The term molecule may or may no ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

and

structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such a ...

. It is the

conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a ...

hydrazoic acid Hydrazoic acid, also known as hydrogen azide or azoimide, This also contains a detailed description of the contemporaneous production process. is a compound with the chemical formula . It is a colorless, volatile, and explosive liquid at room tem ...

Organic azide An organic azide is an organic compound that contains an azide (–) functional group. Because of the hazards associated with their use, few azides are used commercially although they exhibit interesting reactivity for researchers. Low molecular w ...

s are

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

s with the formula , containing the azide

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the r ...

. The dominant application of azides is as a

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the ...

air bag An airbag is a vehicle occupant-restraint system using a bag designed to inflate extremely quickly, then quickly deflate during a collision. It consists of the airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. T ...

Preparation

Sodium azide is made industrially by the reaction of

nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and ha ...

, with

sodium amide Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white ...

liquid ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

as solvent: : Many inorganic azides can be prepared directly or indirectly from sodium azide. For example,

lead azide Lead(II) azide is an inorganic compound. More so than other azides, is explosive. It is used in detonators to initiate secondary explosives. In a commercially usable form, it is a white to buff powder. Preparation and handling Lead(II) azide i ...

, used in

detonator A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electr ...

s, may be prepared from the metathesis reaction between

lead nitrate Lead(II) nitrate is an inorganic compound with the chemical formula Pb( NO3)2. It commonly occurs as a colourless crystal or white powder and, unlike most other lead(II) salts, is soluble in water. Known since the Middle Ages by the name plumb ...

and sodium azide. An alternative route is direct reaction of the metal with

silver azide Silver azide is the chemical compound with the formula . It is a silver(I) salt of hydrazoic acid. It forms a colorless crystals. It is a well-known explosive. Structure and chemistry Silver azide can be prepared by treating an aqueous solution ...

dissolved in liquid ammonia. Some azides are produced by treating the carbonate salts with

Bonding

Azide is

isoelectronic Isoelectronicity is a phenomenon observed when two or more molecules have the same structure (positions and connectivities among atoms) and the same electronic configurations, but differ by what specific elements are at certain locations in th ...

with

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

cyanate Cyanate is an anion with the structural formula , usually written . It also refers to any salt containing it, such as ammonium cyanate. It is an isomer of the much less stable fulminate anion .William R. Martin and David W. Ball (2019): "Sma ...

nitronium ion The nitronium ion, , is a cation. It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion . It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule , or the protonation of nitric ...

and

cyanogen fluoride Cyanogen fluoride (molecular formula: FCN; IUPAC name: carbononitridic fluoride) is an inorganic linear compound which consists of a fluorine in a single bond with carbon, and a nitrogen in a triple bond with carbon. It is a toxic and explosive gas ...

NCF. Per

valence bond theory In chemistry, valence bond (VB) theory is one of the two basic theories, along with molecular orbital (MO) theory, that were developed to use the methods of quantum mechanics to explain chemical bonding. It focuses on how the atomic orbitals of ...

, azide can be described by several

resonance structure In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or ''forms'', also variously known as ''resonance structures'' or ' ...

s; an important one being

Reactions

Azide salts can decompose with release of nitrogen gas. The decomposition temperatures of the alkali metal azides are: (275 °C), (355 °C), (395 °C), and (390 °C). This method is used to produce ultrapure alkali metals: : Protonation of azide salts gives toxic

in the presence of strong acids: : Azide as a

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elect ...

forms numerous

transition metal azide complex Transition metal azide complexes are coordination complexes containing one or more azide (N3−) ligands. Structure and bonding Azide is a pseudohalide but more nucleophilic than chloride. As a monodentate ligand, azide binds through one of th ...

es. Some such compound are more shock sensitive. Many inorganic covalent azides (e.g., chlorine, bromine, and iodine azides) have been described. The azide anion behaves as a nucleophile; it undergoes

nucleophilic substitution In chemistry, a nucleophilic substitution is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The ...

for both aliphatic and aromatic systems. It reacts with epoxides, causing a ring-opening; it undergoes Michael-like conjugate addition to 1,4-unsaturated carbonyl compounds. Azides can be used as precursors of the

metal nitrido complex Metal nitrido complexes are coordination compounds and metal clusters that contain an atom of nitrogen bound only to transition metals. These compounds are ''molecular'', i.e. discrete in contrast to the polymeric, dense nitride materials that ar ...

es by being induced to release , generating a metal complex in unusual oxidation states (see ''

high-valent iron High-valent iron commonly denotes compounds and intermediates in which iron is found in a formal oxidation state > 3 that show a number of bonds > 6 with a coordination number ≤ 6. The term is rather uncommon for hepta-coordinate compounds of ...

'').

Disposal

Azides decompose with nitrite compounds such as

sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite ...

when acidified. This is a method of destroying residual azides, prior to disposal. In the process, nitrogen, nitrogen oxides, and hydroxides are formed: : :

Applications

About 251 tons of azide-containing compounds are produced annually, the main product being sodium azide.Horst H. Jobelius, Hans-Dieter Scharff "Hydrazoic Acid and Azides" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. Sodium azide is the propellant in automobile

airbag An airbag is a vehicle occupant-restraint system using a bag designed to inflate extremely quickly, then quickly deflate during a collision. It consists of the airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. T ...

s. It decomposes on heating to give nitrogen gas, which is used to quickly expand the air bag: : Heavy metal azides, such as

, , are shock-sensitive detonators which decompose to the corresponding metal and nitrogen, for example: :

Silver azide Silver azide is the chemical compound with the formula . It is a silver(I) salt of hydrazoic acid. It forms a colorless crystals. It is a well-known explosive. Structure and chemistry Silver azide can be prepared by treating an aqueous solution ...

and

barium azide Barium azide is an inorganic azide with the formula . It is a barium salt of hydrazoic acid. Like most azides, it is explosive. It is less sensitive to mechanical shock than lead azide. Preparation Barium azide may be prepared by reacting sodi ...

are used similarly. Some organic azides are potential rocket propellants, an example being 2-dimethylaminoethylazide (DMAZ) .

Safety

Azides are

explosophore Explosophores are functional groups in organic chemistry that give organic compounds explosive properties. History The term was first coined by Russian chemist V. Pletz in 1935 and originally mistranslated in some articles as plosophore. Also o ...

s and poisons. Sodium azide is as toxic as

sodium cyanide Sodium cyanide is a poisonous compound with the formula Na C N. It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its hi ...

(with an oral of 27 mg/kg in rats) and can be absorbed through the skin. Heavy metal azides, such as

are

primary Primary or primaries may refer to: Arts, entertainment, and media Music Groups and labels * Primary (band), from Australia * Primary (musician), hip hop musician and record producer from South Korea * Primary Music, Israeli record label Works ...

high explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ...

s detonable when heated or shaken. Heavy-metal azides are formed when solutions of sodium azide or HN₃ vapors come into contact with heavy metals or their salts. Heavy-metal azides can accumulate under certain circumstances, for example, in metal pipelines and on the metal components of diverse equipment (

rotary evaporator A rotary evaporator (rotovap) is a device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation. When referenced in the chemistry research literature, description of the use of this technique and ...

s, freezedrying equipment, cooling traps, water baths, waste pipes), and thus lead to violent explosions.

References

External links

Synthesis of organic azides
recent methods
Synthesizing, Purifying, and Handling Organic Azides
{{Authority control Azides