Atomistry » Boron » Chemical properties » Boron trihydride
Atomistry »
  Boron »
    Chemical properties »
      Boron trihydride »

Boron trihydride, B2H6

Boron trihydride or boro-ethane, B2H6 has been mentioned that the compound B4H10 is very unstable. When kept over mercury at the ordinary temperature it decomposes with the formation of a gaseous hydride B2H6 and hydrogen. The rate of decomposition is greatly augmented by ultraviolet light, but not appreciably by sunlight. The change is practically complete at 100° after one hour.

Boron trihydride is a colourless gas possessing a repulsive odour which recalls that of B4H10, and also that of hydrogen sulphide. Its vapour density corresponds with the molecular formula B2H6. The hydride melts at -169° and boils at -87° C. The vapour pressure of the liquid at various temperatures is as follows: -

Temp. °C-130°-120°-112°-110°-100°-90°-87°
Vap. press, (in cms.)41022.425406576

Boron trihydride is fairly stable, but it slowly decomposes even at the ordinary temperature. When heated with a free flame, solid, but not liquid, hydrides are produced; when sparked, boron is deposited and non-volatile hydrides of unpleasant odour are produced. In the presence of air it gives rise to solids containing both boron and oxygen, and when exploded with oxygen it reacts thus: -

B2H6 + 3O2 = B2O3 + 3H2O.

It dissolves in carbon disulphide, and the solution decolorises bromine; it does not react with dry hydrogen chloride, but combines readily with dry ammonia.

Boron trihydride reacts with water to give boric acid and hydrogen: -

B2H6 + 6H2O = 2H3BO3 + 6H2.

Like the hydride B4H10, it gives a hypoborate with alkali hydroxide, but some hydrogen is evolved immediately the gas and. the hydroxide come into contact. The hypoborate slowly decomposes, and the final result may be expressed thus: -

B2H6 + 6NaOH = 2Na3BO3 + 6H2.

Last articles

Zn in 7VD8
Zn in 7V1R
Zn in 7V1Q
Zn in 7VPF
Zn in 7T85
Zn in 7T5F
Zn in 7NF9
Zn in 7M4M
Zn in 7M4O
Zn in 7M4N
© Copyright 2008-2020 by
Home   |    Site Map   |    Copyright   |    Contact us   |    Privacy