Abstract
‘Water as ice(s)’ describes the sixteen known crystalline phases of ice, starting with normal ice, as well as a potential seventeenth phase called cubic ice, for which they may be evidence elsewhere in the universe. The different crystalline structures of ice are shown on a phase diagram that depicts how changes in pressure and temperature affect the structure of ice. The Bernal–Fowler rules of ice structures are also explained. Ordered arrangements of water molecules all show four-coordinated geometry, but water shows great molecular versatility under pressure: hydrogen bond lengths and OOO angles can vary when forming the high pressure ice structures.
