A dodecazinc silicotungstate K20Na2[Zn6(OH)7(H2O)(Si2W18O66)]2·34H2O (1) has been synthesized and characterized by X-ray crystallography, elemental analysis, infrared, UV-vis spectroscopy, cyclic voltammetry, acid–base titration, and DFT calculations. The twelve zinc atoms between the two [Si2W18O66]16− frameworks make this complex more stable hydrolytically than the heteropolytungstate ligands, [Si2W18O66]16−, themselves. The structurally unique central Zn12 core is formed by the fusion of two [Zn6(OH)7(H2O)]5+ units through two edge-sharing Zn6 atoms. DFT B3LYP calculations give HOMO–LUMO and (HOMO − 1)–LUMO energy gaps of ∼3.65 and 3.91 eV, respectively, as compared to the band gap in ZnO of 3.35 eV.
