The in-situ high-pressure structures of wulfenite have been investigated by means of angular dis- persive X-ray diffraction with diamond anvil cell and synchrotron radiation. In the pressure up to 22.9 GPa, a pressure-induced scheelite-to-fergusonite transition is observed at about 10.6 GPa. The pressure dependence for the lattice parameters of wulfenite is reported, and the axial compression coefficients Kao ----- -1.36 × 10^-3 GPa^-1 and Kc0 = -2.78× 10^-3 GPa^-1 are given. The room-temperature isothermal bulk modulus is also obtained by fitting the P-V data using the Murnaghan equation of state.
In-situ high-pressure energy dispersive X-ray diffraction experiments of malachite have been performed using diamond anvil cell and synchrotron radiation. The highest recorded pressure is up to 17.4 GPa. The experimental results reveal that malachite experienced two phase transitions at 0.7 and 7.8 GPa, and the last one is reversible.
LIU YingxinQIN ShanLI HaijianLI XiaodongLI YanchunLIU Jing
