Abstract In the hydrosilylation of 1-hexene with dichlorosilane, many phosphine complexes of group VIII metals, Ni, Ru, Rh, PD and Pt, were found to be active catalysts, giving n- hexyldichlorosilane exclusively. Tris (triphenylphosphine) chlororhodium was found to be the most convenient and effective catalyst for the selective synthesis of mono- organodichlorosilanes.