Английская Википедия:Boron triazide

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Шаблон:Chembox

Boron triazide, also known as triazidoborane, is a thermally unstable compound of boron and nitrogen with a nitrogen content of 92.1 % (by the standard atomic weight). 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.[1]

Preparation

The first method is by the addition of diborane to a solution of hydrazoic acid in diethyl ether at a temperature range between −20 °C and −10 °C. This synthesis proceeds via the intermediates monoazidoborane, Шаблон:Chem2, and diazidoborane, Шаблон:Chem2.[1]

Шаблон:Chem2

The compound can also be obtained by passing boron tribromide vapor over solid silver azide in high vacuum.[2]

Шаблон:Chem2

A similar gas-phase synthesis uses the spontaneous reaction of boron trichloride with hydrazoic acid.[3][4]

Шаблон:Chem2

Properties

The compound forms colorless crystals that are only stable at low temperatures. Above −35 °C, an explosive decomposition may occur.[1] In the gas phase, generated boron triazide decomposes at room temperature within 60 minutes via loss of nitrogen gas to form boron nitrides with formulas Шаблон:Chem2 and BN. These reactions can also be initiated photochemically by UV radiation in the compounds absorption range at about 230 nm.[3][4][5]

Шаблон:Chem2
Шаблон:Chem2

In contact with water, it undergoes hydrolysis to hydrazoic acid and boron trioxide.[3]

Шаблон:Chem2

Reaction with other azides like sodium azide or lithium azide yields the corresponding tetraazidoborate complexes.[1][6]

Шаблон:Chem2
Шаблон:Chem2

The parent tetraazidoboric acid, Шаблон:Chem2, can be obtained at temperatures lower than −60 °C.[1]

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, pyrazine or 2,2,6,6-tetramethylpiperidine have potential for this usage.[7] The gas-phase decomposition of the compound is also of interest as a method of coating surfaces with boron nitride.[3]

References

Further reading


Шаблон:Azides