Chemical elements
  Boron
    Isotopes
    Energy
    Production
    Application
    Physical properties
    Chemical properties
      Boron Hydrides
      Tetraborodecahydride
      Borobutane
      Hexaborododecahydride
      Borohexylene
      Boron trihydride
      Boro-ethane
      Decaborotetradecahydride
      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
      Borohydrates
      Hypoborates
      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

Boron carbide, B6C






Boron carbide, B6C was isolated in small quantities by Joly in 1883 from among the products of the interaction, in a carbon crucible, of boron sesqui-oxide and aluminium. Later it was prepared in quantity by Moissan, by heating to 3000° in the electric furnace a mixture of sugar carbon and amorphous boron contained in a carbon crucible. A cheaper method of preparation consists in employing boron sesqui-oxide and petroleum coke as starting materials, the former being fed through a hollow graphite electrode on to a layer of the latter contained in a graphite crucible which forms the other electrode. The product is purified from graphite by many treatments with boiling nitric acid and potassium chlorate, followed by treatment with boiling sulphuric acid.

Boron carbide forms brilliant black crystals, of density 2.51, and melts at 2350°. The carbide conducts electricity. It is extremely hard (harder than silicon carbide) and can be used in diamond polishing. It is not affected by mineral acids at the boiling temperature, sulphur at 500°, nitrogen, phosphorus, bromine, or iodine at a bright red heat. It is slowly attacked by oxygen at 1000°, and by chlorine at a somewhat lower temperature. When fused with potassium hydroxide it is decomposed with the evolution of carbon monoxide.

The so-called carbide BC is a mixture of the preceding carbide and graphite (Tucker and Bliss).
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