Synthesis and crystal structure determination of a novel α-dawson mixed-valence octadecatungstoperchlorate

The ‘heteropoly-blue’ species, [NBun4]3[Cl2WVWVI17O62], prepared by exposure to UV light, has been structurally determined by X-ray diffraction; the anion contains randomly distributed WV and WVI in a 1 : 17 ratio and is the first reported mixed-valence heterotungstate which contains two chlorine heteroatoms.