Chemical elements
    Physical properties
    Chemical properties
      Boron Hydrides
      Boron trihydride
      Boron halogen
      Boron trifluoride
      Hydrofluoboric acid
      Potassium borofluoride
      Fluoboric acid
      Perfluoboric acid
      Boron subchloride
      Boron trichloride
      Boron tribromide
      Boron tri-iodide
      Oxides of Boron
      Tetraboron trioxide
      Boron dioxide
      Tetraboron pentoxide
      Boron sesqui-oxide
      Boron trioxide
      Boric anhydride
      Boric Acids
      Orthoboric acid
      Boric acid
      Boracic acid
      Complex Boric Acids
      Perboric Acid and Perborates
      Sodium perborate
      Sodium hyperborate
      Potassium perborate
      Rubidium perborate
      Ammonium perborate
      Barium perborate
      Boron sesquisulphide
      Boron trisulphide
      Boron pentasulphide
      Boron selenide
      Boron nitride
      Boron amide
      Boron imide
      Boron phosphide
      Boron phospho-iodides
      Boron carbide
      Boron thiocyanate
      Boron Alkyls
      Boron trimethyl
      Boron Silicides and

Boroethane, B2H6

The action of chlorine and bromine on this hydride of boron has been studied by Stock, Kuss, and Priess. Chlorine causes explosions at ordinary temperatures, but bromine reacts slowly, even in the light; at 100°, however, the change is complete in a few hours. One half of the halogen used up is recovered as halogen hydride, i.e. the reaction is one of substitution, and boroethane behaves as a saturated compound. The maximum valency of boron towards hydrogen is accordingly four.

Excess of halogen leads to the production of the unimolecular halides, BX3, and not to B2X6. In order to trace the mechanism of these changes, the action of the halogens on excess of the boron hydride was studied and the following conclusions reached. The initial products are such products as B2H4X2 and B2H3X3, which speedily decompose, without the elimination of halogen hydride, yielding B2H5X and B2H6 on the one hand, and BX3 on the other. Thus, of the various halogenated derivatives theoretically possible, a mixture of the extremes is produced. No evidence of the existence of BHX2, BH2X, B2HX5, and B2H2X4 could be obtained.

Boroethane monochloride, B2H5Cl

Boroethane monochloride, B2H5Cl, is a spontaneously inflammable gas. The monobromide, B2H5Br, is a colourless gas with an irritating odour. It melts at 104° and boils at c. 10° C. The vapour pressure is as follows: -

Temp. °C.-80°-70°-60°-50°-40°-30°-20°-10°-5°
Vap. press, in mms.3916305395162255335

It burns with a pale green flame and fumes in the air owing to its reaction with water: -

B2H5Br + 3H2O = B2O3 + HBr + 5H2.

It immediately reacts with potassium hydroxide to form the hypoborate KOBH3. It does not react with sodium, however, to any extent, so that the hydride B4H10 cannot be thus produced.
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