In situ high temperature Raman and DFT analysis of cerium fluoride and oxyfluoride structures in molten FLiNaK.

In order to investigate the species in the FLiNaK–CeF3 and FLiNaK–CeF3–Li2O melts, in situ high temperature Raman spectroscopy was used with the aid of density functional theory (DFT) calculation. In molten FLiNaK, the CeF63− octahedra affected by alkali cations were identified to be the predominan species. Binuclear cerium oxyfluoride anions Ce2OF84− and Ce2OF106− were formed after adding O2− into the molten FLiNaK‐CeF3 (20 mol%) mixtures. Both of these two species were predicted to have Ce−O−Ce geometries with two CeF4/CeF5 moieties bridged by a single oxygen atom. [ABSTRACT FROM AUTHOR]