Complexation of a heptanuclear polyoxotantalate anion with K(+): formation of a supramolecular [K6-(mu-OH2)6-(OH2)8](6+) ring structure.

Hydrolysis of TaV in the presence of KOH and cis-inositol (ino) resulted in the formation of the heptanuclear polyoxotantalate anion [Ta7O12(H-3ino)6]-7 with a double adamantane core; its structure is stabilized by a surrounding [K6-(μ-OH2)6-(OH2)8]6+ ring.