BINARY CRABIDWS, BORIDES AND SILICIDES, SUCH AS TUNGSTEN CARBIDE, HAVING AN AVERAGE PARICLE SIZE OF LESS THAN A MICRON, ARE PREPARED BY REACTING A PAIR OF SUITABLE REACTANTS SUCH AS TUNGSTIC OXIDE AND CALCIUM CARBIDE, IN A MOLTEN METAL HALIDE BATH SUCH AS SODIUM CHLORIDE, AT A TEMPERATURE OF BETWEEN 200 AND 1200*C. IN THE PRESENCE OF AN ALKALI METAL OR ALKALINE EARTH METAL REDUCING AGENT. THE BINARY COMPOUNDS THUS PRODUCED ARE PARTICULARLY USEFUL IN PREPARING HARD, DENSE REFRACTORY MATERIALS.