“…In the IR spectra of Na 5 Fe 2.5 paraB and Na 4 Cu 3 paraB, the characteristic peaks at 975, 950, 932, 867, 676 and 488 cm À1 , and at 972, 937, 926, 872, 675 and 493 cm À1 , respectively, are attributed to the W O t and W-O-W vibrations in the paratungstate anion, which are in agreement with previously reported data (Table 1; Qu et al, 2012). The slight peak displacements are due to the effects of different coordination modes of paratungstate B.…”