Ab initio molecular dynamics simulations and Raman spectra of the YbCl3 - KCl and Yb2O3 - YbCl3 - KCl ionic melts

Abstract

A direct reduction of solid ytterbium oxides into the metal in molten salts is a promising environmental friendly process. To understand the phenomena, which occur during the electrochemical ytterbium production, data on the structure of ytterbium-containing oxide-salt melts are required. In this study, using ab initio molecular dynamics and in situ Raman spectroscopy, we bring insight on the local structure of these systems by the examples of YbCl3–KCl chloride melt and Yb2O3–YbCl3–KCl oxide-chloride melt with a Yb2O3 concentration up to 2 mol%. We show that there are octahedral species [YbCl6], which, with an increase in YbCl3 concentration, can combine into a weakly bonded network through the bridging chlorine anions. Ytterbium oxide in the chloride melt dissociates to form [OYb3] ionic groups, which are incorporated into the melt structure.