Phase transition and water incorporation into Eu2Sn2O7 pyrochlore at high pressure

- The high pressure behavior of Eu2Sn2O7 pyrochlore was studied by XRD and spectroscopy methods.
- Pyrochlore oxide transformed to a cotunnite-type high-pressure phase at 34.4 GPa.
- Water insertion into the lattice was observed at ∼24 GPa.
- The water insertion associate with cation disordering.