Background to Proton Studies in Inorganic Materials

The interaction of water with other inorganic solids such as ceramics, glasses and catalysts is often a key scientific and technological problem. Hydrogen species in such cases are invariably bonded to oxygen and can occur in many different forms. Protons can be present in a crystal structure as stoichiometric OH groups, water molecules, or hydro-nium ions. Hydroxyl groups can also play an important role in substitutions such as 

The main drawback anticipated with H MAS NMR is the strength of the homogeneous dipolar interaction between the protons, which would render it difficult to achieve significant line narrowing. An approach to overcoming this is to physically dilute the protons by deuterating the materials. It is fortunate, however, that in inorganic 

Direct proton NMR not only reveals the different proton species present but can also be used to determine the characteristics of the attached framework site. For example. 

By using this relationship, H shifts can reveal subtle differences between proton sites. A recent detailed review of the application of solid state NMR to probe hydrogenbonding by Brunner and Sternberg (1998) includes H data. 

3 Non-stoichiometric proton environments in crystalline and glassy materials. 

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