Water is a curious molecule

Water is a curious molecule with extraordinary properties, which vary depending on temperature and pressure. Life depends on these anomalous characteristics, such as the unusually large heat capacity, high melting and boiling points, high thermal conductivity and surface tension, and shrinking on melting.  

Water is thus of great interest to biologists, chemists, physicists, as well as cosmologists. Despite its simple structure and its obvious importance, it is still poorly understood and many of its aspects, either as a pure substance or as a solvent, are controversial. For more than a century, the combined significance and peculiarity of water inspired scientists to construct conceptual models, which in themselves reproduce the behavior observed. The exploration of structural and binding properties of small water complexes provides a key to understanding bulk water in its liquid and solid phases and to comprehending solvation phenomena.