A Large, Novel Polyoxotungstate: [AsW65O217(H2O)7]26−

Abstract

The largest tungstoarsenate(III) known to date is [AsW65O217(H2O)7]26− (1). This novel polyoxoanion is isolated as its potassium salt in aqueous, acidic medium in good yield. Structural characterization is based on single-crystal X-ray diffraction, 183W NMR, FT-IR spectroscopy, and elemental analysis. The compact structure of 1 with an idealized C2h symmetry (see picture) consists of four inner (β-AsW9O33) and two outer (α-AsW9O33) fragments (red) that are linked together by a total of eleven corner-sharing WO6 octahedra (green, yellow).