[en] Heating methane, ethane and other paraffins with solutions of chlorides of Pt(II) or Pt(IV) in heavy water there was H-D exchange of D₂O with RH molecule. The reaction was inhibited by chloride ions and accompanied by reduction of metal compounds. The investigation of kinetics and mechanism of these reactions has shown that alkyl derivatives of transition metals are the intermediates, the reaction rate increases with electron accepting properties of metal complexes and electron donating properties of C-H containing compounds. C-H bond was found to be activated to some reactions of substitution and dehydrogenation as well. (K.A.)