The cluster {Cu-8(mu(8)-Se)[S2P(OEt)(2)](6)}(0.54){Cu-6[S2P(OEt)(2)](6)}(0.46) (2) was prepared in 78% yield from the reaction of Cu-8(Se)[Se2P(OPr)(2)](6) (1) and NH4S2P(OEt)(2) in toluene. The central selenide ion in 2 was characterized by Se-77 NMR at