Substitution of the protons in 12-tungstophosphoric acid by monovalent cations of the Groups 1B and 3B, in particular Ag+ and Tl+, respectively, produces high surface area microporous solids whose morphological properties and numbers of residual protons are dependent upon the relative amounts of the preparative reactants. Temperature-programmed desorption of NH3, H-1 MAS NMR and the isomerization of 1-butene have been employed to demonstrate that both the numbers of protons and the distribution of the acidic strengths are dependent upon the nature of the cation and the preparative proton/cation ratios.