Also found in: Dictionary.



compounds of boron and hydrogen. Boranes containing two to 20 atoms of boron per molecule are known. The simplest borane, BH3, does not exist in a free state; it is known only in the form of complexes with amines, ethers, and so on. The nature of borane bonds is very distinctive: they are electron-deficient compounds—that is, they do not have a sufficient number of electrons to bind all the atoms by means of the usual two-electron valent bonds. In diborane, B2H6, each atom of boron is bound to two atoms of hydrogen by ordinary bonds, but the two boron atoms are bonded by three-center “bridge” bonds, which are formed by the sharing of a pair of electrons by three atoms—two borons and one hydrogen.

The structure of other boranes is still more complex. In contrast to hydrocarbons, boranes form complex spatial structures rather than chains of atoms. The lower boranes are gases (B2H6 and B4H10—tetraborane) and liquids (B5H9—pentaborane); the higher boranes (BioHn—decabo-rane, and others) are solids. Boranes are colorless; they have an unpleasant odor and are extremely poisonous. The lower boranes oxidize easily, are spontaneously inflammable in air at low temperatures (below 100° C), and are easily hydrolized by water to form boric acid, with the liberation of hydrogen. The higher boranes are more stable and less reactive. All boranes decompose to boron and hydrogen at temperatures greater than 700° C.

Diborane is produced by the interaction of boron chloride or boron fluoride with metal hydrides (LiH, NaH, NaBH4, LiA1H4) by the hydrogenation of boron chloride with hydrogen and by other means. The higher boranes are produced through the thermal decomposition of diborane.

The heat of combustion of the boranes is significantly higher than the heat of combustion for other compounds; for this reason, the boranes are of great interest as promising rocket fuels. The compound B2H6. is used to obtain elemental boron and for putting a boride covering on metals. Certain borane derivatives can be used to obtain heat-resistant polymers. Other boranes and certain of their derivatives are extremely toxic.


Nekrasov, B. V. Osnovy obshchei khimii, vol. 2. Moscow, 1967.
Mikhailov, B. M. Khimiia borovodorodov. Moscow, 1967.
Zhigach, A. F., and D. S. Stasinevich. Khimiia gidridov. Leningrad, 1969.
Paushkin, la. M. Khimiia reaktivnykh topliv. Moscow, 1962.


References in periodicals archive ?
Borane dimethylsulphide (10M solution), 5ml (50 m mol) was taken in a 200ml round-bottom flask, provided with a rubber stoppred side arm and fitted with a condenser connected to a mercury bubbler.
Boranes manifesto que el "poco exito de la Patrulla Fronteriza en frenar el paso de los indocumentados por la frontera entre Arizona y Sonora (Mexico)" ha propiciado que los rancheros quieran tomar la justicia en sus manos.
El alcalde de Douglas, Ray Borane condeno la accion luego de que recibiera por correo una de las invitaciones del grupo en la que solicitan a los visitantes "disfrutar del desierto" mientras protegen las propiedades "de la inmigracion ilegal".
Other topics include electron-deficient intermediates, multiple bonding to silicon, and polyhedral boranes (with applications to nanotechnology).
The complexing ability of amine towards borane was monitored by [sup.
1:2 stoichiometry ratio was followed for the reduction, because the reduced amine forms a complex with borane, hence excess borane needed to make the reduction convenient.
Reagent DMANB has certain advantages over the currently available borane reagents such as borane.
The authors cover practical features of stability, reactivity, and workup, as well as such aspects of allylboration as the stereochemical control elements, including relative diastereoselection with crotylboranes, induced (internal) diastereoselection with chiral carbonyl compounds, auxiliary-controlled enantio-selective allylations with chiral borane reagents, and recent advances in catalysis of allylboration.
CONTEXT: Dimethylamine borane (DMAB) is a reducing agent used in nonelectric plating of semiconductors.
KEY WORDS: chemical decontamination, dimethylamine borane, neurotoxicity, polyneuropathy, semiconductor plating.