Structure and compression of crystalline argon and neon at high pressure and room temperature

Argon and neon crystallize in the face-centered cubic structure (Fm3m, z = 4) at 11.5±0.5 and 47.4±0.5 kbar, respectively, at 293 K. Single-crystal cell dimensions were obtained at 82 kbar for argon and 144 kbar for neon with high-pressure, x-ray diffraction techniques. The data were corrected to 0 K and fitted to a second-order Murnaghan equation of state with V0 and K0 constrained to results obtained in low-temperature experiments. No solid-solid phase transitions are observed to the highest pressures studied.