On the mechanism of the pressure-induced wurtzite- to NaCl-type phase transition in CdS: an X-ray diffraction study

The high-pressure behavior of wurtzite-type CdS up to the transition pressure of about 2.5 GPa was studied using single-crystal X-ray diffraction techniques. The fit of the Birch-Murnaghan equation of state gave a bulk modulus K=62.8(8)GPa with a fixed pressure derivative K′=4. During the phase transformation the single crystals were destroyed but the obtained material showed a pronounced preferred orientation. Therefore, orientation relations between the low-pressure wurtzite-type phase and the high-pressure NaCl-type phase could be determined. Apart from slight tilts with unknown origin between the unit cells of both structures, the observations support the usual transition mechanism.