X-ray Diffraction of Oxygen under Pressure in a Neon Medium

Solid oxygen under pressure transforms to the e phase above 10 GPa. New X-ray diffraction measurements on a fine powder of e oxygen embedded in neon (5% of oxygen) and on pure oxygen, performed at ESRF, are presented. The evolution with pressure of the lattice parameters and of the molar volume up to 38 GPa are discussed.