Cobalt Subsilicide, Co₂Si

Di-cobalto Silicide or Cobalt Subsilicide, Co₂Si, is obtained in grey metallic crystals of density 7.1 at 17° C. and 7.28 at 0° C. by heating cobalt with 10 per cent, of silicon in carbon crucibles in an electric furnace. It may also be prepared by heating cobalt in the vapour of silicon tetrachloride at 1200-1300° C. It is not magnetic, thereby differing from the corresponding iron compound. It dissolves readily in aqueous hydrogen fluoride; less rapidly in hydrogen chloride. It melts at 1327° C.