Key Takeaways
- Scientists have discovered a new form of ice, Ice XXI, the 21st known crystalline phase of water.
- It was created under immense pressure equivalent to 34,000 elephants on one square meter.
- The discovery could provide insights into the icy environments of moons like Europa and Enceladus.
In a major scientific breakthrough, researchers have created a new type of ice using pressure so immense it’s comparable to the weight of 34,000 elephants concentrated on a single spot. This newly discovered phase, named Ice XXI, is the 21st known crystalline form of water.
Groundbreaking Discovery in High-Pressure Science
The Korea Research Institute of Standards and Science (KRISS) led the international team that identified Ice XXI. The discovery occurred under ultrahigh pressure conditions exceeding 2 gigapascals (GPa) at room temperature, observed at unprecedented microsecond timescales.
To put this in perspective, 2 GPa is the enormous pressure used to synthesise diamonds in laboratories or what materials experience deep inside the Earth’s mantle.
How Scientists Created the New Ice
While ordinary ice forms by cooling water below 0°C, crystallisation depends as much on pressure as temperature. At room temperature, water pressurised above 0.96 GPa normally transitions to Ice VI.
Researchers used a new dynamic diamond anvil cell (dDAC), developed at KRISS, to supercompress microscopic water samples beyond 2 GPa without mechanical shock. This enabled exploration of previously inaccessible states of water.
Capturing Fleeting Crystallisation Moments
KRISS scientists collaborated with the European XFEL, the world’s largest X-ray free-electron laser facility, and international partners from Germany, Japan, the USA, and the UK. Together, they captured the rapid freezing and melting processes of water.
The high-resolution observation revealed complex multiple crystallisation pathways, leading to the unexpected identification of Ice XXI.
Unique Properties of Ice XXI
The distinct structure of Ice XXI features a significantly larger and more complex unit cell than prior ice phases, with a unique flattened rectangular crystal lattice shape. This new ice form is metastable at room temperature and pressure ranges where Ice VI typically dominates.
KRISS Principal Investigator Dr. Lee Geun Woo highlighted how combining dDAC technology and XFEL capabilities allowed them to capture fleeting crystallisation moments, opening new frontiers in high-pressure science.
Implications for Extraterrestrial Research
Co-first author Dr. Lee Yun-Hee noted that the density of Ice XXI mirrors that of high-pressure ice layers believed to exist inside the icy moons of Jupiter and Saturn. This suggests potential insights into extraterrestrial icy environments and the origins of life under extreme conditions.
This international research milestone advances fundamental understanding of water’s behaviour in extreme environments and promises to impact high-pressure physics, planetary science, and material science. The discovery creates future opportunities to find novel materials beyond Earth.
