Synthesis, molecular structure and chemical properties of a new tungstosilicate with an open Wells–Dawson structure, (alpha)-[Si2W18O66]^16–

Acidification of K10A-(alpha)-[SiW9O34] in aqueous solution leads to the formation of (alpha)-[Si2W18O66]16–, built up from two A-(alpha)-{SiW9O34} subunits, which reacts with metal cations to form potassium and mixed potassium– transition metal complexes.