X-ray Diffraction to 302 Gigapascals: High-Pressure Crystal Structure of Cesium Iodide

+ See all authors and affiliations

Science  03 Nov 1989:
Vol. 246, Issue 4930, pp. 649-651
DOI: 10.1126/science.246.4930.649


X-ray diffraction measurements have been carried out on cesium iodide (CsI) to 302 gigapascals with a platinum pressure standard. The results indicate that above 200 gigapascals CsI at 300 K has a hexagonal close-packed crystal structure with the ideal c/a ratio of 1.63 ± 0.01. The crystal structure and pressure-volume relations converge at high pressure with those of solid xenon, which is isoelectronic with CsI. The results indicate a significant loss of ionic bonding in the hexagonal close-packed metallic phase of CsI at ultrahigh pressure.

Related Content