The catalytic cleavage under hydrogen of the C-H and C-C bonds of alkanes with conventional catalysts requires high temperatures. Room-temperature hydrogenolysis of simple alkanes is possible on a well-defined and well-characterized zirconium hydride supported on silica obtained by surface organometallic chemistry. The surface structure resulting from hydrogenolysis of (=SiO)Zr(Np)(3) (Np, neopentyl) was determined from the extended x-ray absorption fine structure (EXAFS) and H-1 and Si-29 solid-state nuclear magnetic resonance and infrared (IR) spectra. A mechanism for the formation of (=SiO)(3)Zr-H and (=SiO)(2)SiH2 and the resulting low-temperature hydrogenolysis of alkanes is proposed. The mechanism may have implications for the catalytic formation of methane, ethane, and lower alkanes in natural gas.