P–V–T equation of state of molybdenite (MoS₂) by a diamond anvil cell and in situ synchrotron angle-dispersive X-ray diffraction

The pressure–volume–temperature (P–V–T) equation of state (EoS) of a natural molybdenite (MoS₂) has been measured at high temperature up to 700 K and high pressures up to 18.26 GPa, by using in situ angle-dispersive X-ray diffraction and diamond anvil cell. Analysis of room-temperature P–V data to a third-order Birch–Murnaghan EoS yields: V₀=107.0±0.1 ų, K₀=67±2 GPa and K′₀=5.0±0.3. With K′₀ fixed to 4.0, we obtained: V₀=106.7±0.1 ų and K₀=74.5±0.8 GPa. Fitting of our P–V–T data by means of the high-temperature third order Birch–Murnaghan equations of state, gives the thermoelastic parameters: V₀=107.0±0.1 ų, K₀=69±2 GPa, K′₀=4.7±0.2, (∂K/∂T)_P=−0.021±0.003 GPa K⁻¹, a=(2.2±0.7)×10⁻⁵ K⁻¹ and b=(2.9±0.8)×10⁻⁸ K⁻². The temperature derivative of the bulk modulus and thermal expansion coefficient of MoS₂ are obtained for the first time. Present results are also compared with previously studies determined the elastic properties of MoS₂ and WS₂