A quantum chemical study of the hydrating shell influence on the structural and vibrational properties of beryllium aqua and hydroxo complexes

Clusters of beryllium aqua and hydroxo complexes surrounded by the hydrating shell of 30-50 water molecules modelled by the effective fragment potential method have been investigated by a computational approach. The results have been compared with the existing experimental and calculated data and discussed in terms of structural parameters, partial charges, Mayer's bond orders and frequencies of the total symmetric stretching vibration Be-O. It was found that the hydration changes the electron structure of the most polar complex, shortens and strengthens the Be-O bonds and increases the frequencies of the Be-O stretching vibrations by 12-16% in all the complexes in comparison with the free ones. Evidence of negative partial molar volume of the beryllium cation has been obtained.