DecatantalateThe Last Member of the Group 5 Decametalate Family

A tetra-n-butylammonium (TBA) salt of [Ta10O28]6– was synthesized by heating TBA6[H2Ta6O19] in toluene for a prolonged period. X-ray structural analysis of TBA6[Ta10O28]·6H2O revealed that the anion has the decametalate structure and is isostructural with the decavanadate and decaniobate anions [a = 15.8517(8) Å, b = 19.364(1) Å, c = 21.935(1) Å, β = 93.638(1)°, V = 6719.4(6) Å3, Z = 2, and space group P21/n at 292(2) K].