Equation of state of KI up to 150 GPa

ABSTRACT

The equation of state of potassium iodide, KI, has been determined up to 156 GPa at 298 K by angular-dispersive X-ray diffraction in diamond-anvil-cell. Helium pressure transmitting medium was used to minimize non-hydrostatic stress on the sample. The B2 phase is stable at least between 2 and 156 GPa. Pressure–volume data were fitted using a Rydberg–Vinet equation of state. The volume, isothermal bulk modulus and its pressure derivative of B2-KI at ambient pressure are $V_0=79.2\pm 2.5$ ${\text{Å}}^3$, $K_0=11.9\pm 1.2$ GPa and $K_0^{\prime }=6.01\pm 0.11$. It allows using KI as a pressure calibrant in high pressure experiments.

KEYWORDS:

• Diamond anvil cell
• pressure transmitting medium
• X-ray-diffraction

Acknowledgments

We acknowledge synchrotron ESRF for the provision of beamtime under proposal HC-5077 and synchrotron SOLEIL. We thank Florent Occelli for his help with samples loading.

Disclosure statement

No potential conflict of interest was reported by the author(s).