“…In fact, the α -quartz structure, with the proposed parameters20, gives rise to atypical, very short, O–O distances. After this, Oganov and colleagues21 used density functional theory-based structure searching to predict several phases of the H 2 –H 2 O mixture, but these searching methods are restricted in the number of atoms; thus, any large clathrate-sized unit cells can easily be missed. In this work we study, by means of Raman spectroscopy, the C 0 phase of the water–hydrogen mixture, produced at ∼400 MPa and recovered at room pressure and liquid nitrogen temperature, still containing a large fraction of molecular hydrogen.…”