FIELD: chemistry. SUBSTANCE: invention relates to chemical engineering of submicron aluminium nitride crystals in the form of hexagonal prisms and a combination of a hexagonal prism with a dipyramid and pinacoid, which can be used in creating elements of nano-, micro- and optoelectronics, as well as luminescent-active micro-size sensors for medical and biological purposes. Granules of metal aluminium are mixed with powder of aluminium trifluoride in ratio 1:1–3:1 and mixture is heated to temperature of formation of aluminium sub-fluoride vapours, equal to 1050–1150 °C, in an ammonia atmosphere fed into space above liquid aluminium with volumetric feed rate below 50 ml/min at absolute pressure 0.03–0.07 MPa. EFFECT: technical result consists in obtaining aluminium nitride crystals with the same fractional size from 70 nm to 1 mcm.