Structure of the (O@Nb6O18)8– and (O@Ta6O18)8– Clusters: A Quantum-Chemical Study

The symmetry (Oh) and internuclear distances in (O@Nb6O18)8–/aq, (O@Ta6O18)8–/aq, O@Nb6O18(Na/K)8, and O@Ta6O18(Na/K)8 clusters were determined by DFT PBE0 calculations. The models of a multicharged cluster in a polarizable aqueous medium and a cluster stabilized by the Na+ and K+ cations provide the agreement of calculations for the hexaniobate and hexatantalate octaanions wuth X-ray diffraction data.