Synthesis of a new vdW compound (Xe)(Cl$_{\mathrm{2}})$ and ionic XeCl$_{\mathrm{2}}$ under pressure

A number of xenon compounds have been synthesized at high pressure-high temperature conditions recently. Most of them have been shown to be molecular, van der Waals compounds. Recently, it has been shown that in the case of Xe-O system, pressure induces changes in the xenon valence state thereby confirming the hypothesis that pressur induces hyper-valency in xenon compounds. Indeed, this causes XeF$_{\mathrm{2}}$ to transition to XeF$_{\mathrm{4}}$, XeF$_{\mathrm{6}}$ and ultimately to XeF$_{\mathrm{8}}$. In the Xe-Cl$_{\mathrm{2}}$ system, we observe the formation of a vdW compound that can be transformed to a non-molecular compound at higher pressures and under laser heating. Using a combination of XANES and XRD at 16-BM-D of HPCAT, we have experimental evidence of valence changes that manifest in huge Raman intensities in the vdW compound.