PROTON TRANSPORT MECHANISM IN CONCENTRATED AQUEOUS-SOLUTIONS AND SOLID HYDRATES OF ACIDS

H-1 and O-17 diffusion coefficients D(H) and D(o) of aqueous hydrochloric acid of different molarity have been measured. "Structure diffusion triggered by molecular diffusion", i.e. the proton conduction mechanism suggested for dilute aqueous solutions of acids, could be extended to concentrated solutions. For these and for some solid proton conducting hydrates this mechanism approaches the vehicle mechanism (molecular diffusion) as its limiting case for low solvent concentration. The ratio D(H)/D(O) provided experimental proof for intermolecular proton transfer in thermodynamic equilibrium.