Aluminium nitride (A1N) is obtained as small yellow crystals when aluminium is strongly heated in nitrogen.
Boron nitride BN is formed when boron is burned either in air or in nitrogen, but can be obtained more readily by heating to redness in a platinum crucible a mixture of one part of anhydrous borax with two parts of dry ammonium chloride.
After fusion, the melt is well washed with dilute hydrochloric acid and then with water, the nitride remaining as a white powder.
The fixation of nitrogen as a nitride has not been attended with commercial success.
Mehner patented heating the oxides of silicon, boron or magnesium with coal or coke in an electric furnace, and then passing in nitrogen, which forms, with the metal liberated by the action of the carbon, a readily decomposable nitride.