Using　ab　initio　method　and　natural　bond　analyses,　the　electronic　structures　of　dinuclear　tungsten　cluster　[Et4N](2)[W2S4(TDT)(2)]　and　the　cubane-like　tetranuclear　mixed-metal　clusters　W2MM＇S-4(TDT)(2)(PPh3)(2)　(M,M＇　=　Cu,Ag)　have　been　studied.　It　is　shown　that　the　tungsten　clusters　are　similar　with　the　molybdenum　clusters.　Besides　the　metal-metal　and　metal-sulfur　direct　bonding,　the　metal-sulfur-metal　interactions　can　be　discerned　by　the　multi-center　d-p　pi　bondings,　which　exist　among　the　metal　and　bridging(or　terminal)　sulfur　atoms.　The　research　results　discover　that　the　3c　pi(W-S-b-W)　and　pi(W-S-t)　bonds　in　the　dinuclear　cluster　built　some　＇active　centers＇.　The　nature　of　multi-centered　d-p　pi　bondings　and　their　effects　on　the　stability　and　reactivities　in　[2+1+1]　addition　reactions　of　the　tetranuclear　clusters　are　discussed.　(C)　1998　Elsevier　Science　B.V.