Abstract: Refractory borides or carbides are prepared by contacting an alkali-metal ducible metal chloride or silicon tetrachloride with boron trichloride or carbon tetrachloride in an inert solvent in the presence of an alkali metal, the metal chloride or silicon tetrachloride and the boron trichloride or carbon tetrachloride being present in an amount about stoichiometrically equivalent to the boride or carbide to be prepared and the alkali metal being present in an amount about stoichiometrically equivalent to the amount of chloride in the metal chloride or silicon tetrachloride and the boron trichloride or carbon tetrachloride, until all chloride present has reacted with the alkali metal to form alkali metal chloride, separating the inert solvent to leave a solid residue containing a metal boride, silicon carbide or metal carbide precursor together with the alkali metal chloride, and calcining the residue while separating the alkali metal chloride until the precursor is converted to the refractory boride or carbide