A REINVESTIGATION OF THE PREPARATION OF TUNGSTEN-OXIDE HYDRATE WO3, 1/3H(2)O

A reinvestigation of the synthesis procedures of WO3, 1/3H(2)O via the preparation and dehydration of H2WO4, H2O has been carried out in order to check the stoichiometry of WO3, 1/3H(2)O, the parent material of the important hexagonal WO3. The formation of WO3, 1/3H(2)O during dehydration reaction of H2WO4, H2O via the solution was observed to require the presence of sodium in the reaction system, resulting in sodium incorporation in the WO3, 1/3H(2)O phase. The minimal level of sodium in the WO3, 1/3H(2)O phase was found to be 160 ppm; sodium levels up to 1000-3000 ppm were also found to be incorporated in the WO3, 1/3H(2)O structures. A shift in the c parameter of the WO3, 1/3H(2)O cell has been found to be connected with the change in the concentration of incorporated sodium. The average size of the octagonal platelets of WO3, 1/3H(2)O was found to be connected with the sodium concentration in the solid phase. A modification in infrared absorption spectra has been observed. (C) 1995 Academic Press, Inc.