Ice IX

For the fictional material in Cat's Cradle, see Ice-nine.

For other uses, see Ice-nine (disambiguation).

Ice IX is a form of solid water stable at temperatures below 140 K and pressures between 200 and 400 MPa. It has a tetragonal crystal lattice and a density of 1.16 g/cm³, 26% higher than ordinary ice. It is formed by cooling ice III from 208 K to 165 K (rapidly—to avoid forming ice II). Its structure is identical to ice III other than being hydrogen-ordered.

Ordinary water ice is known as ice I_h in the Bridgman nomenclature. Different types of ice, from ice II to ice XVI, have been created in the laboratory at different temperatures and pressures.

See also

• Ice for other crystalline forms of ice.

References

• Bridgman, P. W. (1937) J. Chem. Phys. 5, 964.

External links

• London South Bank University Report