Just out: Discovery of a low-density filled-ice phase in nitrogen hydrate at high pressure
Communications Chemistry, Published online: 11 June 2026; doi:10.1038/s42004-026-02030-6While the stability of nitrogen clathrate hydrates at moderate pressures is well established, the behavior of the water-nitrogen system at higher pressures, relevant for the deep interiors of large icy moons and water-rich exoplanets, remains underexplored. Here, the authors use neutron diffraction, Raman spectroscopy and crystal structure prediction to map the high-pressure phase diagram of nitrogen hydrate up to 16 GPa at room temperature, reporting a sequence of structural transformations from sI/sII clathrates to hexagonal and tetragonal phases and orthorhombic filled-ice structures above 1.8 GPa.
