XRD study of MIT crystal structure at different temperatures

The structure of MIT was studied by X-ray powder diffraction in ambient atmosphere at different temperatures from 25 °C to 100 °C. The Rietveld method was employed to refine the structure and determine the concentration of Hg vacancy concentration. The results show that Hg vacancy concentration in MIT crystal introduced by high Hg vapor pressure is 1.88% at room temperature, and the lattice constant is about 0.63163 nm. As the temperature increasing, the concentration of Hg vacancy increases, and the lattice constant of MIT decreases first and then increases.