Chemical elements
    Physical properties
    Chemical properties
      Aluminium subfluoride
      Aluminium trifluoride
      Aluminium trichloride
      Aluminium tribromide
      Aluminium iodide
      Aluminium chlorate
      Aluminium perchlorate
      Aluminium bromate
      Aluminium periodate
      Aluminium suboxide
      Aluminium sesqui-oxide
      Aluminium peroxide
      Aluminium hydroxides
      Tricalcium aluminate
      Sodilim aluminate
      Aluminium sesqui-sulphide
      Aluminium selenide
      Aluminium telluride
      Aluminium sulphite
      Aluminium sulphate
      Sodium alum
      Potassium alum
      Ammonium alum
      Hydroxylamine alum
      Silver alum
      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
      Aluminosilicic acids aluminosilicates
      Aluminium Borides
      Aluminium Boride
      Aluminium Boride
      Aluminium borocarbides
      Aluminium borate
      Aluminium sodium perborate
    PDB 1a6e-1zca
    PDB 2b8w-3i62
    PDB 3kql-5ukd

Aluminium borocarbides

The researches of Wohler and Deville and of Hampe were concerned mainly with the interaction of boron oxide and aluminium in either clay or graphite crucibles. Joly showed that when a graphite crucible was employed, the following products were obtained, the relative quantities varying with the conditions of the experiment: (i.) aluminium boride AlB2; (ii.) aluminium boride AlB12; (iii.) yellow crystals containing boron, aluminium, and carbon; and (iv.) boron carbide B6C. Hampe's experiments led him to believe in the existence of a definite borocarbide Al3C2B48. Later, Biltz obtained crystals of definite composition, corresponding to the formula Al3C2B44. The method of preparation was similar to that described for the preparation of the boride AlB12, except that soot (2 grams) was added to the mixture. The product, after treatment with water, concentrated hydrochloric acid, and then the warm, dilute acid for some days, consists of sparkling yellow crystals mixed with a few black crystals of AlB12.

The crystals have a density at 18° of 2.590 ± 0.006, are harder than corundum and softer than diamond. Towards reagents they resemble the boride AlB12, but are more resistant towards mineral acids.

It is difficult to believe that the formulae given by Hampe and Biltz represent definite chemical compounds. Probably each chemist obtained products of definite composition simply because the conditions of experiment were not sufficiently varied. Crystals of quite different composition have been prepared by Binet du Jassonneix, by heating aluminium with excess of boron in a graphite crucible in an electric arc furnace. They are yellow, transparent, and occur in six-sided plates; mixed with them are crystals of boron carbide, from which they cannot be completely separated. The crystals are attacked slowly by dilute hydrochloric acid, quickly by nitric acid. After allowing for mechanically admixed boron carbide, the average composition was Al, 64 per cent.; B, 15 per cent.; C, 21 per cent.; but different preparations varied considerably in composition.

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