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

Abstract

The pressure–volume–temperature (P–V–T) equation of state (EoS) of a natural molybdenite (MoS2) has been measured at high temperature up to 700K and high pressures up to 18.26GPa, 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±0.1Å3, K0=67±2GPa and K′0=5.0±0.3. With K′0 fixed to 4.0, we obtained: V0=106.7±0.1Å3 and K0=74.5±0.8GPa. 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±0.1Å3, K0=69±2GPa, K′0=4.7±0.2, (∂K/∂T)P=−0.021±0.003GPaK−1, a=(2.2±0.7)×10−5K−1 and b=(2.9±0.8)×10−8K−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.