Nucleation of ice in confined geometry

Neutron diffraction studies have been made of ice nucleation in various forms of porous sol-gel silicas and ordered aluminosilicates. It is shown that the crystal structure of the ice exhibits significant variation according to the conditions and often has a diffraction pattern composed of a hybrid with both cubic and hexagonal ice characteristics. The ice structures appear defective/disordered in a complex manner but have common characteristics in terms of temperature variation studies. New studies of water in ordered mesoscopic (MCM-41) structures give results that appear to indicate ''frustrated nucleation''.