Chemical elements
  Aluminium
    Isotopes
    Energy
    Preparation
    Physical properties
    Chemical properties
      Aluminium subfluoride
      Aluminium trifluoride
      Aluminium trichloride
      Aluminium tribromide
      Aluminium iodide
      Aluminium chlorate
      Aluminium perchlorate
      Aluminium bromate
      Aluminium periodate
      Aluminium suboxide
      Alumina
      Aluminium sesqui-oxide
      Aluminium peroxide
      Aluminium hydroxides
      Aluminates
      Tricalcium aluminate
      Sodilim aluminate
      Aluminium sesqui-sulphide
      Aluminium selenide
      Aluminium telluride
      Aluminium sulphite
      Aluminium sulphate
      Alums
      Sodium alum
      Potassium alum
      Ammonium alum
      Hydroxylamine alum
      Silver alum
      Pseudo-alums
      Aluminium dithionate
      Aluminium selenite
      Aluminium selenate
      Aluminium chromate
      Aluminium molybdate
      Aluminium silicomolybdate
      Aluminium tungstate
      Aluminium silicotungstate
      Aluminium phosphotungstate
      Aluminium nitride
      Aluminium phosphide
      Aluminium arsenide
      Aluminium nitrate
      Aluminium Phosphates
      Basic aluminium arsenite
      Aluminium carbide
      Aluminium carbonate
      Aluminium thiocyanate
      Aluminium oxalate
      Aluminium alkyls
      Aluminium Hydrocarbon
      Aluminium acetylacetonate
      Aluminium silicide
      Aluminium silicates
      Leucite
      Nephelite
      Spodumene
      Topaz
      Beryl
      Tourmaline
      Axinite
      Sodalite
      Hauynite
      Kaolinite
      Aluminosilicic acids aluminosilicates
      Aluminium Borides
      Aluminium Boride
      Aluminium Boride
      Aluminium borocarbides
      Aluminium borate
      Aluminium sodium perborate
    Applications
    PDB 1a6e-1zca
    PDB 2b8w-3i62
    PDB 3kql-5ukd

Aluminium Boride, AlB2






The following methods of preparation are due to Wohler and Deville: (i.) a mixture of boron oxide and carbon is heated to redness in chlorine, and the gaseous products (boron trichloride and carbon monoxide) passed over aluminium heated to whiteness in a porcelain tube; free aluminium is removed from the product by solution in hydrochloric acid or sodium hydroxide; (ii.) potassium borofluoride (8 pts.), potassium chloride (9 pts.), sodium chloride (7 pts.), and aluminium (5 pts.) are heated together for half an hour at the melting-point of silver, and the product isolated as before. Binet du Jassonneix has produced it readily by heating to 1300°, in a stream of hydrogen, a fragment of aluminium contained in a crucible brasqued with boron.

The boride AlB2 is a semi-metallic looking solid, which crystallises in six- sided plates belonging to the monoclinic system. It is said by Wohler and Deville, and also by Binet du Jassonneix, to be nearly black, but distinctly copper-coloured by reflected light; Joly describes it as golden-yellow in colour. The boride is unaffected by air at a red heat, dissolves slowly in hot concentrated hydrochloric acid or sodium hydroxide, and rapidly in hot nitric acid.

When prepared by the method of Binet du Jassonneix, it is accompanied by a small proportion of brown crystals of octahedral habit. These latter crystals are formed in abundance when the boride AlB2 is heated with an excess of boron at 1400°, or when a mixture of boron and aluminium powders is heated to 1300° in hydrogen. They are heavier than the boride AlB2 and far more resistant towards nitric acid.


© Copyright 2008-2012 by atomistry.com