Synthesis, spectroscopic and structural studies on vanadium(V) periodates

Reactions of V2O5 or NH4VO3 with periodic acid under basic conditions followed by acidification result in precipitates of general formula M5V4I2O19(OH)·nH2O (M = Na, n = 10; M = K, n = 5; M = Rb, n = 4; M = Cs, n = 3; M = NH4, n = 11). These are amorphous, and attempts at crystallisation failed, but spectroscopic measurements and analysis show similar features and compositions throughout this series of compounds. V and I K-edge extended X-ray absorption fine structure (EXAFS) spectra show a polymeric structure containing edge-linked octahedral periodate and square-pyramidal vanadyl groups.