A proposal for the structuring of water

In spite of much work, many of the properties of water remain puzzling. A fluctuating network of water molecules, with localised icosahedral symmetry, is proposed to exist derived from clusters containing, if complete, 280 fully hydrogen-bonded molecules. These are formed by the regular arrangement of identical units of 14 water molecules that can tessellate locally, by changing centres, in three-dimensions and interconvert between lower and higher density forms. The structure allows explanation of many of the anomalous properties of water including its temperature-density and pressure-viscosity behaviour, the radial distribution pattern, the presence of both pentamers and hexamers, the change in properties and 'two-state' model on supercooling and the solvation properties of ions, hydrophobic molecules, carbohydrates and macromolecules. The model described here offers a structure on to which large molecules can be mapped in order to offer insights into their interactions. (C) 1999 Elsevier Science B.V. All rights reserved.