A clear correlation between the H-1 NMR chemical shift and the stretching vibration frequency of hydroxyl groups in solids could be stated. Surface hydroxyl groups in zeolites and related materials have been taken into account as well as water molecules in solid hydrates and strongly hydrogen-bonded protons in inorganic solids.Cationic hydroxyl groups in zeolites (CaOH, MgOH) as well as CaOH groups in calcium phosphates differ significantly from the correlation found for the above-mentioned types of hydroxyls.
