Boron triazide, also known as triazidoborane, is a thermally unstable compound of

boron Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three ...

and

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

with a nitrogen content of 92.1 % (by the

standard atomic weight The standard atomic weight of a chemical element (symbol ''A''r°(E) for element "E") is the weighted arithmetic mean of the relative isotopic masses of all isotopes of that element weighted by each isotope's abundance on Earth. For example, ...

). Formally, it is the triazido derivative of

borane Borane is an inorganic compound with the chemical formula . Because it tends to dimerize or form adducts, borane is very rarely observed. It normally dimerizes to diborane in the absence of other chemicals. It can be observed directly as a c ...

and is a covalent inorganic

azide In chemistry, azide (, ) is a linear, polyatomic anion with the formula and structure . It is the conjugate base of hydrazoic acid . Organic azides are organic compounds with the formula , containing the azide functional group. The dominant ...

. 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 The Ludwig Maximilian University of Munich (simply University of Munich, LMU or LMU Munich; ) is a public university, public research university in Munich, Bavaria, Germany. Originally established as the University of Ingolstadt in 1472 by Duke ...

Preparation

The first method is by the addition of

diborane Diborane(6), commonly known as diborane, is the chemical compound with the formula . It is a highly toxic, colorless, and pyrophoric gas with a repulsively sweet odor. Given its simple formula, borane is a fundamental boron compound. It has att ...

to a solution of

hydrazoic acid Hydrazoic acid, also known as hydrogen azide, azic acid 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 ...

diethyl ether Diethyl ether, or simply ether, is an organic compound with the chemical formula , sometimes abbreviated as . It is a colourless, highly Volatility (chemistry), volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It belongs ...

at a temperature range between −20 °C and −10 °C. This synthesis proceeds via the intermediates monoazidoborane, , and diazidoborane, . : The compound can also be obtained by passing

boron tribromide Boron tribromide, BBr3, is a colorless, fuming liquid compound containing boron and bromine. Commercial samples usually are amber to red/brown, due to weak bromine contamination. It is decomposed by water and alcohols. Chemical properties Boron ...

vapor over solid

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

in high vacuum. : A similar gas-phase synthesis uses the spontaneous reaction of

boron trichloride Boron trichloride is the inorganic compound with the formula BCl3. This colorless gas is a reagent in organic synthesis. It is highly reactive towards water. Production and structure Boron reacts with halogens to give the corresponding trihalides ...

with hydrazoic acid. :

Properties

The compound forms colorless crystals that are only stable at low temperatures. Above −35 °C, an explosive decomposition may occur. In the gas phase, generated boron triazide decomposes at

room temperature Room temperature, colloquially, denotes the range of air temperatures most people find comfortable indoors while dressed in typical clothing. Comfortable temperatures can be extended beyond this range depending on humidity, air circulation, and ...

within 60 minutes via loss of nitrogen gas to form boron nitrides with formulas and BN. These reactions can also be initiated

photochemically Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible (400–750&nb ...

by UV radiation in the compounds absorption range at about 230 nm. : : In contact with water, it undergoes hydrolysis to hydrazoic acid and

boron trioxide Boron trioxide or diboron trioxide is the oxide of boron with the formula . It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide or boria. It h ...

. : Reaction with other azides like

sodium azide Sodium azide is an inorganic compound with the formula . 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 highly soluble in water and is acutely poisonou ...

lithium azide Lithium azide is the lithium salt of hydrazoic acid. It is an unstable and toxic compound that decomposes into lithium and nitrogen when heated. Preparation It can be prepared by metathesis reaction between sodium azide and lithium nitrate or ...

yields the corresponding tetraazidoborate complexes. : : The parent tetraazidoboric acid, , can be obtained at temperatures lower than −60 °C.

Uses

Due to the low stability, the compound itself is not used as a high-energy substance. However, the tetraazidoborate derivatives and adducts with bases such as

quinoline Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N. It is a colorless hygroscopic liquid with a strong odor. Aged samples, especially if exposed to light, become yellow and later brown. Quinoline is only sl ...

pyrazine Pyrazine is a heterocyclic aromatic organic compound with the chemical formula C4H4N2. It is a symmetrical molecule with point group D2h. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. It is a ''"deliquescent crystal or wax-lik ...

2,2,6,6-tetramethylpiperidine 2,2,6,6-Tetramethylpiperidine, abbreviated TMP, HTMP, or TMPH, is an organic compound of the amine class. In appearance, it is a colorless liquid and has a "fishy", amine-like odor. This amine is used in chemistry as a hindered base ( hindered am ...

have potential for this usage. The gas-phase decomposition of the compound is also of interest as a method of coating surfaces with boron nitride.

Preparation

Properties

Uses

References

Further reading