In accordance with this invention, there is provided a lubricating composition comprising a major amount of an oil of lubricating viscosity and a minor amount of an additive having the formula Mo.sub.2 L.sub.4 wherein L is a ligand selected from xanthates and mixtures thereof and, in particular, xanthates having a sufficient number of carbon atoms to render the additive soluble in the oil. In general, the xanthate ligand, L, will have form about 2 to 30 carbon atoms.