Physicists Discover the Most Complex Forms of Ice Yet

Recommendable! The many wonders of water!

"... Since 1900, scientists have observed more than 20 phases of ice, many of them shaped under extreme conditions. The growing list includes hot ice and even ice that conducts electricity. ...

Over the past decade, computer simulations have predicted tens of thousands of possible forms of ice. Though uncommon on our planet, exotic ice may exist in off-Earth environments, from cold and amorphous comet tails to the hot and crushing cores of icy planets.

As physicists put water to the test with improved experimental techniques, they keep finding surprises. “You take water, and just the way you compress it — a little bit faster, a bit slower, up and down, at the right timescale — and then you can find this completely unexpected behavior,” ...

In 2018, an international research group from Europe and Japan created an ambitious computer simulation of the dynamics of water molecules that aimed to predict undiscovered forms of ice. The result was a catalog of over 75,000 phases, each characterized by a slightly different way that the water molecules could fit together when subjected to a different combination of temperature and pressure. ...

In 2025, Bove’s team in Lausanne discovered a smaller but in some ways stranger metastable phase of ice. In a study published in Nature, they reported the first observation of plastic ice VII. This is a variation of ice VII, a high-pressure phase of ice, that appears when the ice is heated to around 500 degrees Celsius. ..."

Physicists Discover the Most Complex Forms of Ice Yet | Quanta Magazine "Scientists keep detecting new forms of ice. According to simulations, there could be many more left to find."

Fig. 1: Phase diagram of the QENS experiment and investigated thermodynamic paths.

a, Experimental phase diagram of water in the investigated P–T region, melting lines are reproduced from refs. 31,43. The region of stability of plastic ice VII from numerical simulations8 is shown with white dashed lines, pressures and temperatures are shifted to match the experimental melting line. The measured thermodynamic points are represented as circles with colours corresponding to the phase attribution (a selection of thermodynamic points from previous experiments34 are represented as squares). Error bars on the pressure determination are of ±0.5 GPa for the high-pressure isobars, whereas they are of 0.1 GPa for the thermodynamic points close to the melting as the melting was used to calibrate the pressure.