X-Ray diffraction and equation of state of hydrohalite, a major component of water-rich planetary bodies.

Observations from space probes strongly support the presence of dissolved ionic species (e.g. Mg, Na, Cl, SO4) in deep oceans of icy moons like Ganymede, Europa, Enceladus and Titan to pressures of several GPa. Eutectic salt saturated phases (e.g. hydrohalite for H2O-NaCl) are expected at the surface and interior of these planetary bodies through their thermal evolution. Accurate P-V-T equations of state (EoS) of relevant materials are of capital importance to better constrain the structure, dynamic and evolution of icy worlds. Even if predicted as a major specie at the surface and interior of icy worlds , no equation of states for hydrohalite exists to date due to the very limited amount of data available in the litterature. We propose to run high-pressure, low temperatures single crystal and powder X-Ray diffraction experiment to characterize the volumes hydrohalite NaCl•2(H2O), in the 50K – 300K and 0 – 2200MPa range.