Angewandte Chemie International Edition
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Inside Cover: Direct Observation of Contact Ion-Pair Formation in Aqueous Solution (Angew. Chem. Int. Ed. 33/2009)
Contact between anions and cations in aqueous solution is rarely observed, especially by direct spectroscopic methods. The Cs8[Nb6O19] polyoxometalate salt with its high negative charge, spherical symmetry, excellent X-ray scattering power, and very good aqueous solubility provides the ideal scenario. In their Communication on page 6136 ff., M. R. Antonio, M. Nyman, and T. M. Anderson present a small-angle X-ray scattering study that reveals how contact ion pairing in solution matches the solid-state structure.