High Pressure X-Ray Study on NiO Isothermal Equation of State up to 50 GPa

The isothermal compression behavior of NiO was studied using the in-situ high pressure X-ray diffraction method with the diamond anvil cell up to 50 GPa. The Murnaghan equation of state for NiO was used to fit the experimental data with the least square method, and the equation parameters are: B0=223 GPa, B0'=4.21. The pressure dependence of the ratio c/a of NiO indexed by hexagonal lattice can be expressed approximately as c/a=2.450~1.56910-3(GPa) in the range of our experimental pressures. No phase transition was observed under high pressure and room temperature in present experiment.