Silver and thallium, representatives from the periodic table’s groups 1B and 3B, respectively, were employed as cations to synthesize stoichiometric and nonstoichiometric salts of 12-tungstophosphoric, 12-molybdophosphoric, and 12-tungstosilicic acids. All the solids, except silver 12-molybdophosphate, have high surface areas and microporous structures, as shown from the analysis of nitrogen adsorption-desorption isotherms obtained at 77 degrees K. Powder X-ray diffraction, temperature-programmed desorption, infrared spectroscopy, and H-1 MAS NMR spectroscopy are employed to characterize the synthesized materials.