A new polyanion with Dawson-like constitution: [H2SeW18O60]6 −

A new tungstoselenite, [H2SeW18O60]6 −, was isolated under acidic medium conditions (pH = 1.7)with the monoprotonated ethylamine as cation. It represents the first example of Se-containing polyoxometalate with unusual Dawson-like construction and has fully been characterized both in solid state and in solution. The high-resolution ESI-MS confirmed that the polyanion at least contains two protons and its proton number can be up to six in solution.