Molecular dynamics study of hydrated alkali and halide ions in liquid nitrobenzene

The structure, dynamics and energetics of hydrated alkali and halides ions in bulk nitrobenzene are studied using molecular dynamics computer simulations. The number of water molecules in the ions’ hydration shell (hydration number) and their orientational distribution, hydration water residence time and several important energy terms are calculated and compared with the same quantities in bulk water. The water molecules in the first hydration shell of the ion are more tightly bound to the ion in bulk nitrobenzene than in bulk water as reflected by the longer lifetime in the former case. As the ion size increases, the average hydration number in nitrobenzene decreases, which is the reverse trend to that found in bulk water. The calculated hydration numbers are in reasonable agreement with experimental data.