Oxide solubility and Raman spectra of NdF3-LiF-KF-MgF2-Nd2O3 melts

The solubility of Nd2O3 in NdF3-LiF-MgF2 melts is about 0.08-0.38 mol% when the NdF3 concentration varies from 15 to 30 mol% at 900degreesC. The solubility increases from 0.13 mol% at 750 degreesC to 0.22 mol% at 900 degreesC in the NdF3-LiF eutectic. When MgF2 is added to NdF3-LiF binary melts saturated with Nd2O3, the Nd2O3 solubility seems to decrease slightly at 30 mol% NdF3, while a slight increase was observed with 15 mol% NdF3 in the binary. When dissolving Nd2O3 in the NdF3-LiF eutectic Raman spectroscopy showed that the complex ions NdOFx(x-1)- and Nd2OF(x+3)((x-1)-) may form in the melt. The most reasonable candidates seem to be: NdOF43- and NdOF54- among the mononuclear compounds and Nd2OF106-, Nd2OF84- among the binuclear complexes.