The sodium salt of the double Keggin anion [Fe4Cu2Wlg07oH6]1(>-has been prepared from Na2W04-2H20, Fe(N03)3-9H20, and Cu(CH3C00)2-H20 in water and isolated in cystalline form as Na]0Fe4Cu2WlgO70H6-29H2O: monoclinic, P2,/n, a = 13.079 (3) A, b = 17.772 (4) A, c = 21.104 (7) A, ß = 93.46 (2)°, V = 4896 (2) A1 23, Z = 2, D(calcd) = 3.75 g cm'3 567. This is the first polytungstate ion to contain six paramagnetic centers and the first with four paramagnetic centers bridged by a single oxygen atom. The anion contains two octahedral Cu(II) sites, two octahedral Fe(III) sites, and two tetrahedral Fe(III) sites forming a Cu2Fe4D21 core. The cationic portion of the structure consists of two [Na5022]5+ oxygen-bridged structures draping the anion in necklace fashion. The magnetic susceptibility of the salt was determined for the temperature range 4-374 K; it exhibits strong antiferromagnetic interaction at low temperature.shows a pronounced decrease at about 100 K and approaches a constant value at 20 K. The EPR spectrum in the 77-300 K range consists of a broad feature (1000 G) with little structure centered at about g = 2.2 and a weaker second line at about g = 4.4. The broad line suggests that the six central metal ions participate in the magnetism in this temperature range.

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Die Kondensation von Cu(I)‐thiophenolat, Benzotriazol und einem organischen Isocyanid liefert die Cluster (I), von denen (Ia) röntgenkristallographisch untersucht wird.