High-pressure phase transition and equation of state of CsI

Stuructural properties of CsI at high pressure have been investigated by the use of synchrotron X-ray-diffraction techniques with the diamond-anvil cell at 300 K. The results indicate that the material undergoes a continuous distortion from B2 to an hcp-like phase, which is stable to at least 302 GPa. The intermediate orthorhombic phase is geometrically different from previous assignments and about 10 percent denser. With the new structure, the p-V results of static pressure experiments, shock-wave studies, and theoretical calculations are now in good agreement.