Angewandte Chemie International Edition
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Inside Cover: Phase Transition Accompanied by Transformation of an Elusive Discrete Cyclic Water Heptamer to a Bicyclic (H2O)7 Cluster (Angew. Chem. Int. Ed. 31/2007)
The structures of water that are so far known may be just the tip of the iceberg. In their Communication on page 5925 ff., Mir and Vittal describe a discrete cyclic water heptamer trapped inside a 3D coordination polymer. When the single crystal is cooled from 296 K to 223 K, it undergoes a phase transition with structural transformation to a bicyclic water heptamer containing edge-sharing pentamer and tetramer rings. The background shows the iceberg of Possession Bay, taken with permission from http://www.sgisland.org.