Distinct mechanistic differences in the hydrogen-atom transfer from methane and water by the heteronuclear oxide cluster [Ga2 MgO4](.).

The thermal reactions of the heteronuclear oxide cluster [Ga2 MgO4 ](.+) with methane and water have been studied using state-of-the-art gas-phase experiments in conjunction with quantum-chemical calculations. The significant reactivity differences, favoring activation of the strong OH bond, can be ascribed to a proton-coupled electron transfer (PCET) mechanism operative in the activation of water. This study deepens our mechanistic understanding on how inert RH bonds are cleaved by metal oxides.