Superionic water

Superionic water is a theoretical phase of water under extreme heat and pressure which has properties of both a solid and a liquid.^[1] It is a face-centered cubic lattice form of ice, As of 2013, one of two forms of superionic ice known, the other being a body-centered cubic lattice.^[2]

At high temperatures and pressures, such as in the interior of giant planets, it is argued that water exists as ionic water in which the molecules break down into a soup of hydrogen and oxygen ions, and at even higher pressures as superionic water in which the oxygen crystallises but the hydrogen ions float around freely within the oxygen lattice.^[3]

Properties

Superionic water is thus far theoretical, but predictions have been made about its properties. If it were present on Earth, it would rapidly decompress and explode. Under the conditions theorized to cause water to enter the phase, it is believed that superionic water would be as hard as iron and would glow yellow.^[1] The crystalline structure of superionic water is a face-centered cubic lattice (fcc).^[2]

History of theoretical and experimental evidence

In 1999 Cavazzoni, et al. predicted that such a state would exist for ammonia and water in conditions such as those existing on Uranus and Neptune.^[4] In 2005 Laurence Fried led a team at Lawrence Livermore National Laboratory in California to recreate the formative conditions of superionic water. Using a technique involving smashing water molecules between diamonds and super heating it with lasers they observed frequency shifts which indicated that a phase transition had taken place. The team also created computer models which indicated that they had indeed created superionic water.^[1]

Existence in gas giants

It is theorized that the gas giant planets Uranus and Neptune hold a layer of superionic water.^[5]

References

1. ↑ 1.0 1.1 1.2 Giant planets may host superionic water, Nature, 22 March 2005.
2. ↑ 2.0 2.1 Phys.org, "New phase of water could dominate the interiors of Uranus and Neptune", Lisa Zyga, 25 April 2013
3. ↑ Weird water lurking inside giant planets, New Scientist,01 September 2010, Magazine issue 2776.
4. ↑ Superionic and Metallic States of Water and Ammonia at Giant Planet Conditions, Cavazzoni C., et al. Science, 283. 44 - 46
5. ↑ Charlie Osolin. "Public Affairs Office: Recreating the Bizarre State of Water Found on Giant Planets". Llnl.gov. Retrieved 2010-12-24.