A decanuclear [(Dy6Zn4II)-Zn-III] cluster: a {Zn-4(II)} rectangle surrounding an octahedral {Dy-6(III)}.
An octahedral {Dy-6(III)} cage within a diamagnetic {Zn-4(II)} rectangle is reported, with magnetic relaxation studies revealing single-molecule magnet behaviour for the complex under zero external dc field with U-eff = 43 K and tau(o) = 1 x 10(-5) s.