Reduction of [(RuCl)-Cl-III(P(OMe)(3))(2)](2)(mu-Cl)(2)(mu-S-2) (1) in THF leads to complete removal of the mu-Cl groups to form die tetranuclear complex, [(RuCl)-Cl-II(mu-Cl)(P(OMe)(3))(2)(mu,eta(1),eta(2)-S-2)Ru(P(OMe)(3))(mu-P(OMe)(3)-P,O)](2) (6). The structure of complex 6 consists of a pair of trans-(RuSSRuII)-S-II cores. P-31{H-1}NMR studies elucidate that a monomeric trans-(RuSSRuII)-S-II complex exists in the solution phase and that two trans-(RuSSRuII)-S-II cores form complex 6 in the process of recrystallization.