PURPOSE: To obtain a compd. useful as an abrasive and to improve its hardness and mechanical properties by incorporating elemental aluminum, boron and phosphorus.

CONSTITUTION: A mixture of aluminum phosphide and elemental boron, or aluminum phosphide and boron phosphide, or aluminum phosphide, boron phosphide and elemental boron, is mixed with a powdery or acicular aluminum by >4 weight ratio to the mixture. The mixture is heated at 1100 to 1800°C in an inert gas atmosphere to react in the liquid aluminum matrix. After the reaction is completed, the product is cooled at 0.1 to 30 K/min. cooling rate to obtain a ternary element compd. in a granular state having >80 μm average particle size. The obtd. compd. mostly consists of regular icosahedron B12 units and contains aluminum atoms, phosphorus atoms and optionally boron atoms present among the B12 units, with each element present by 1 to 98 mol.%. The obtd. compd. has high resistance against chemical attacks.