Researchers discover new form of ice

UNLV researchers have discovered a new form of ice.

Solid water, or ice, can be used to make a variety of solid materials, like diamond or graphite, because of its variable temperature and pressure. There are at least 20 solid forms of ice known to us, and water is exceptional in this aspect.

A team of scientists working in UNLV's Nevada Extreme Conditions Lab pioneered a new method for measuring the properties of water under high pressure. The water sample was squeezed between the tips of two diamonds and frozen into ice. The ice was temporarily melted by a laser-heating technique and then re-crystallised into a powder-like collection of tiny crystals.

The team observed the water ice transition from a known cubic phase, Ice-VII, to the newly discovered intermediate phase, Ice-VIIt, before settling into another known phase, Ice.

The transition to Ice-X, when water stiffens aggressively, occurs at much lower pressures than previously thought by the UNLV student who led the work.

It is likely a common ingredient within the mantle of Earth as well as in large moons and water-rich planets outside of our solar system, and it is unlikely we will find this new phase of ice anywhere on the surface of Earth.

The findings were reported in the journal Physical Review B.

The research team was studying the behavior of high-pressure water in distant planets.

A standard feature of high pressure physics is the placement of a sample of water between the tips of two diamonds. The researchers were able to recreate the pressures found at the center of the Earth by applying force to the diamonds.

The water sample between the diamonds was squeezed between the oxygen and hydrogen atoms to create a variety of different arrangements.

The first-of-its-kind laser-heating technique allowed scientists to observe a new phase of water ice, but the team also found that the transition to Ice-X occurred at pressures nearly three times lower than previously thought. The topic of this transition has been debated for a long time.

The transformation to an ionic state occurs at much lower pressures than was thought before.

The work makes us understand the composition of exoplanets. The Ice-VIIt phase of ice could exist in abundance in the upper mantle of expected water rich planets outside of our solar system, meaning they could have conditions for life.

Pressure driven symmetry transitions in dense H 2 O ice were published in the journal Physical Review B.

More information: Zachary M. Grande et al, Pressure-driven symmetry transitions in dense H2O ice, Physical Review B (2022). DOI: 10.1103/PhysRevB.105.104109 Journal information: Physical Review B Citation: Researchers discover new form of ice (2022, March 18) retrieved 18 March 2022 from https://phys.org/news/2022-03-ice.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.