Peculiarities of quadrupolar relaxation in electrolyte solutions were established via comparison of the data obtained from proton and deuteron resonances. It has been shown that quadrupole coupling constants (QCC) of douterons depend not only on internal electron structure of molecule or ion, but on solution structure as well. To interpret the experimental results quantum-chemical calculations of QCC of deuterons in different molecular complexes simulating different solution substructures were carried out. Density functional theory (DFT) method with hybrid B3LYP functional was used for all calculations.