Water : Liquid-state Anomalies and Solvation

“Despite its familiarity as a solvent in chemical and biochemical systems, water as a liquid presents a number of interesting and anomalous properties. For example, there is a large negative volume change on melting, the existence of multiple glassy phases and a number of anomalous thermodynamic and kinetic properties, such as a temperature of maximum density at atmospheric pressure. The connections between the liquid-state anomalies of water and its behaviour as a solvent are still not well-understood, though biological structure and function are crucially dependent on an aqueous environment. Over the past decade, waterlike anomalies have been demonstrated in liquids with very diverse underlying interactions, such as ionic melts and colloidal fluids. Using computer simulations in conjunction with some ideas from liquid state theory, it is shown that the existence of water-like anomalies in this diverse range of systems can be understood in terms of the relationships between structural order, entropy and molecular mobility. Implications for hydration of simple solutes are discussed.”