The sol-gel process that occurs in a mixture of titanium butoxide and concentrated hydrochloric acid was studied using Cl-35 nuclear magnetic resonance (Cl-35-NMR) spectroscopy. Density functional theory (DFT) calculations with long-range corrections were also employed to calculate absolute shielding values (sigma) to characterize the NMR spectrum. Two isomeric 5-coordinate water adducts of Ti[O(CH2)(3)CH3](3)Cl center dot H2O, which were predicted by Gibbs free energy calculations using DFT, were determined as the main products in the mixture.