On stoichiometric hydroxyapatite [Ca-10(PO4)(6)(OH)(2), Ca/P = 1.67] the partial oxidation of methane at 973 K yields carbon oxides as the principal products, with a selectivity to CO of approximately 40%, while on calcium oxide, phosphate, and sulfate, C-2 hydrocarbons predominate. On introduction of tetrachloromethane (TCM) into the feedstream the selectivity to CO is increased to 71% on hydroxyapatite while, in contrast, with the remaining calcium compounds the conversion of methane and/or the selectivities to C-2 compounds, particularly to C2H4, are enhanced.