Process for synthesis of molybdenum sulfide dimers

A process for chemical conversion of a cyclopentadienyl molybdenum tricarbonyl first dimer having the formula ›MoCp(CO).sub.3)!.sub.2 wherein Cp represents a cyclopentadienyl moiety, in which first dimer at least one cyclopentadienyl moiety contains at least one carboxyl- or carbonyl- containing ring substituent and in which the two cyclopentadienyl molybdenum tricarbonyl units of the first dimer are directly connected by a single bond between the two molybdenum atoms, to a resinous composition having repeating units having the formula (MoCp).sub.2 S.sub.4 and in each of which repeating units the two cyclopentadienyl molybdenum units are connected through four sulfido bridging ligands and the repeating units are connected by bridging sulfide ligands, the process comprising reacting the first dimer with elemental sulfur at a temperature in the range of from about 110.degree. C. to about 120.degree. C. in an effective solvent for the first dimer and in the presence of a solid adsorbent support for the resinous composition produced, such that the resinous composition produced is deposited thereon to form a supported resinous composition.