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# Ultrahigh pressure phase transition in ice

## Details

**Authors** Osmond et al.

**Year** 2026

**Publisher** Nature Materials

**Discipline** Chemistry

**Secondary disciplines** Materials Science, Physics

[Read it at the publisher](https://doi.org/10.1038/s41563-026-02732-1) 
10.1038/s41563-026-02732-1

## In authors' words

### What they found (results)

Diamond-anvil-cell X-ray diffraction and Raman spectroscopy show ice X undergoes a first-order phase transition to a new orthorhombic phase (ice XXII, Pbcm symmetry) above 308(5) GPa, stable to at least 340(5) GPa.

## Commentary

### In short

A qualitatively new, symmetry-distinct material category only exists once a sharp pressure threshold is crossed, produced by the whole crystal lattice reorganizing collectively rather than any single component changing.

**Patterns it shows** D, S

**Added** 2026-09-08

**How to cite this** Osmond et al. (2026). Ultrahigh pressure phase transition in ice. Nature Materials.