Two new multi-cobalt-containing heteropolyoxotungstates

A new polyoxotungstate K4Na6Co2(H2O)12{Co(H2O)4[Co2(H2O)10Co4(H2O)2(SiW9O34)2]2} · 40H2O (1) has been obtained in an aqueous solution system. The polyoxoanion framework of 1 consists of two sandwich-type polyoxoanions [Co4(H2O)2(B-α-SiW9O34)2] connected together by a [CoO2(H2O)4] cluster to constitute the sandwich dimer which is covalently linked together with another four isolated Co2+ cations by four μ2-O atoms.