Synthesis and characterization of XeAr2 under high pressure.

Abstract

The binary Xe-Ar system has been studied in a series of high pressure diamond anvil cell experiments up to 60GPa at 300K. In-situ x-ray powder diffraction and Raman spectroscopy indicate the formation of a van der Waals compound, XeAr2, at above 3.5GPa. Powder x-ray diffraction analysis demonstrates that XeAr2 adopts a Laves MgZn2-type structure with space group P63/mmc and cell parameters a = 6.595 Å and c = 10.716 Å at 4GPa. Density functional theory calculations support the structure determination, with agreement between experimental and calculated Raman spectra. Our DFT calculations suggest that XeAr2 would remain stable without a structural transformation or decomposition into elemental Xe and Ar up to at least 80GPa.