Reduction of CuCl2-graphite intercalation compound (GIC) is known to bring about fine copper particles dispersed in the graphite matrix. When the products were subsequently allowed to react with chlorine gas at 450°C, copper particles were chlorinated in the graphite matrix. The degree of chlorination was found to be dependent on the initial chlorine pressure. It should be emphasized that copper atoms mostly stayed behind in the graphite during the reduction and the subsequent chlorination.