The fluoride route to Lindqvist clusters: Synthesis and crystal structure of layered hexatantalate Na8Ta6O19·26H2O

Alkali-induced hydrolysis of fluoro-complexes of Ta and Nb affords one-pot synthesis of well crystallized compounds containing Lindqvist hexatantalate [Ta6O19]8 − and hexaniobate [Nb6O19]8 − ions. As an example, Na8Ta6O19·26H2O, a polyoxometalate with a remarkably complex layered structure was synthesized using the new method. An advantage of the proposed synthetic approach is that it can be easily embedded into existing technological flowcharts for the processing of Nb and Ta allowing direct synthesis of polyoxometalates from inexpensive fluoride precursors.