The thermal expansion of 2H-MoS₂, 2H-MoSe₂ and 2H-WSe₂ between 20 and 800°C

The hexagonal cell dimensions a and c of 2H-MoS₂, 2H-MoSe₂ and 2H-WSe₂ have been measured over the temperature range 20 to 800 °C. In all three compounds a and c increased non-linearly with temperature, the linear thermal expansion coefficient of c being greater than that of a. Above 500°C the compounds begin to decompose in vacuum.