Breakthrough Discovery of a New Ice Phase: Ice XXI

In an unprecedented scientific achievement, a team of researchers has identified a completely new pathway for water crystallization, leading to the discovery of a new and previously unknown phase of ice known as “Ice XXI.” This discovery enhances our understanding of how ice forms under extreme pressure and temperature conditions.

How Ice Forms Under High Pressure

Water typically turns into ice when its temperature drops below the freezing point. However, pressure can play a crucial role in the crystallization process, allowing ice to form at temperatures significantly higher than the normal boiling point when subjected to sufficiently high pressures.

For instance, when water is compressed to more than 0.96 gigapascals at room temperature, it transforms into Ice VI. These processes lead to a complex rearrangement of the hydrogen-bonded network between water molecules, resulting in diverse ice structures depending on the surrounding conditions.

A History of Ice Research

Over the past century, scientists have identified 20 different crystalline forms of ice by adjusting pressure and temperature. These forms exist within a wide range exceeding 2000 Kelvin in temperature and 100 gigapascals in pressure. One of the most complex areas in the water phase diagram is the region between atmospheric pressure and 2 gigapascals, where more than ten different ice phases converge.

Advanced Techniques Behind the Discovery

A team from the Korea Research Institute of Standards and Science (KRISS) managed to create a highly compressed liquid state, where water remained liquid at pressures exceeding 2 gigapascals, more than double the pressure typically required for crystallization. This was achieved using a dynamic diamond anvil cell (dDAC), a high-pressure tool developed at KRISS.

The dDAC is characterized by reducing mechanical shocks and shortening the pressure application time from tens of seconds to just 10 milliseconds, allowing water to be pushed deeply into the Ice VI pressure range while remaining in the liquid state.

International Collaboration in Research

This discovery involved 33 researchers from South Korea, Germany, Japan, the United States, and England, in collaboration with scientists at the European XFEL and DESY. The project was proposed and led by the Korea Research Institute of Standards and Science (KRISS) under the supervision of Dr. Lee Jeon Woo.

Significance of the Discovery

The new ice, Ice XXI, features a large and complex unit cell compared to other known phases. This discovery may provide deeper insights into ice formation in similar environments, such as the high-pressure ice layers within Jupiter’s and Saturn’s moons, potentially offering new clues for exploring the origins of life in extreme conditions in space.

Conclusion

The discovery of Ice XXI represents a significant step forward in understanding high-pressure physics and planetary sciences. The use of advanced techniques such as the dDAC and European XFEL facilities contributed to these groundbreaking results. As research in this field continues, we may witness further discoveries that open new horizons in science.