Two models are studied for the anchored system Mo 2 (η 3 -C 3 H 5 ) 4 /SiO 2 : united model (UM) and separated model (SM). Total energies, bond orders, diatomic energies, and parametric diatomic binding energies of selected bonds were calculated for Si 8 O 2 4 H 1 6 , Mo 2 (η 3 -C 3 H 5 ) 4 , and Mo 2 (η 3 -C 3 H 5 ) 4 /Si 8 O 2 4 H 1 6 systems, using a CNDO-UHF parametrical method. From the energetic viewpoint, UM is more stable than SM to explain the immobilizing of Mo 2 (η 3 -C 3 H 5 ) 4 on silica. It is observed Mo-H interaction that leads to C-H activation. These results support several features of the generally accepted mechanism for olefin metathesis. An interpretation of these theoretical results was carried by comparing with PAS-FTIR, 1 H and 1 3 C solid-state NMR, and XPS trends.