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.