A new electron precise, six-electron, sulfide-bicapped trinuclear cluster complex [Et4N](4)[Mo-3(IV)(mu(3)-S)(2)(mnt)(6)] (1) has been synthesized, where each Mo-IV atom is seven coordinated. Identical reaction conditions yielded a dimeric complex, [PNP](2)[W-2(V)(mu(2)-S)(2)(mnt)(4)] (2) from the starting W-IV analogue due to oxidation by sulfur formed by the auto-oxidation of H2S. Two stepwise reversible reductions and no oxidation of 2 as observed by cyclic voltammetry are correlated with the nonbonding nature of the lowest unoccupied molecular orbital and deeply buried highest occupied molecular orbital by theoretical calculations at the density-functional theory level.