Preparation and characterization of polyoxometallates of molybdenum, tungsten and their salts

In this work, confirmation of the molecular formula and investigation of the structural stability of the prepared various types of heteropoly acids and their salts by TGA are reported. Specific surface areas of the samples were determined by the BET-single point N-2 adsorption method. Scanning electron microscopy (SEM) was used for the of surface topography of the samples in the sense of crystalline and amorphous states and the acidities of these solid samples were determined based on the color changes of suitable indicator solutions by the way of a butylamine titration method. Impurities, weight ratios and bonding states of the characteristic elements of the samples were determined from XRD, EDX and FTIR studies