The local structure of dilute
CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy
(XAS) at temperatures from room temperature to 800<sup>o</sup>C. This
constitutes the first experiment where dilute Cr speciation is explored in a
molten chloride salt, ostensibly due to the compounding challenges arising from
a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the
stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions
at higher temperature (>700<sup>o</sup>C) prevented confirmation of the
local structure.
Reaction cell for in situ soft x-ray absorption spectroscopy and resonant inelastic x-ray scattering measurements of heterogeneous catalysis up to 1 atm and 250 °C