Compressibility and structural properties of jadeite, NaAlSi₂O₆ at high pressure

The structural properties of jadeite at high pressures (0. 000 1-30 GPa) are investigated using plane-wave pseudopotential density functional theory method. As a function of pressure, the monoclinic cell parameters were calculated and the compressibility coefficients are 0. 002 6, 0. 002 3 and 0. 002 6 GPa^-1, respectively. The bond length, bond angle and distortion variation were studied in order to obtain the information of polyhedral compression. The pressure-volume equation of state was considered in order to obtain the bulk modulus K₀. Comparison between the calculated K₀ values and the experimental data suggested that the model provides reasonable insights into crystallographic and physical properties of jadeite.