Investigation of the preyssler phosphotungstate heteropolyanion, [NaP_5W_(30)O_(110)]~(14-), properties with different counter ions

摘要

Preyssler heteropolytungstophosphate anions with different counter ions, X_xM_y[NaP_5W_(30)O_(110)], where X = H and M = Cs, Ba, La, Ce, Hg, Tl, Pb and Bi, were prepared and the effect of the counter ion on their behavior was investigated by i.r. spectroscopy, surface area measurements (BET), simultaneous thermal analysis (STA), cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). Thermal analyses indicate that the Ce derivative has the highest and the Hg derivative the lowest thermal stability. Only the Cs, Ba and Tl salts show measureable surface area. All heteropolyanions with similar i.r. spectra and electrochemical behavior demonstrate that the heteropolyanion structures are retained. The X-ray photoelectron spectra of the heteropolyacid salts reveal high binding energies for counter ions in comparison with classic salts and strong interaction of counter ion with the oxo oxygen's for H~+ and Cs~+ derivatives.