Ice II is a rhombohedral crystalline form of ice with highly ordered structure. It is formed from ice Ih by compressing it at temperature of 198 K at 300 MPa or by decompressing ice V. When heated it undergoes transformation to ice III.
Ordinary water ice is known as ice Ih, (in the Bridgman nomenclature). Different types of ice, from ice II to ice XV, have been created in the laboratory at different temperatures and pressures.
It is thought that the cores of icy moons like Jupiter's Ganymede may be made of ice II.
- Chaplin, Martin (2007-10-26). "Ice-two structure". Water Structure and Science. Retrieved 2008-01-02.