Electronic absorption spectra of lanthanides in a molten chloride

Electronic absorption spectra of trivalent neodymium in LiCl-KCl eutectic, NaCl-2CsCl eutectic, CaCl2, LiCl, CsCl and mixtures of these at various temperatures were measured, and the variation of the absorption bands, 4G5/2, 2G7/2 ← 4I9/2, were carefully analyzed. The dependence of their molar absorptivity, oscillator strength, and the degree of the energy splitting on temperature and melt composition were determined. As a result, it was suggested that the NdCl63− complex keeps its octahedral symmetry in the NaCl-2CsCl eutectic, while this symmetry is more distorted in LiCl and CaCl2. Based on these data, the chemical status of NdCl63− complex in molten chlorides was discussed.