Internal cation mobility in molten LiCl–NdCl3 system

Internal mobilities of Li+ and Nd3+ cations have been investigated in binary unsymmetrical molten LiCl–NdCl3 system by countercurrent electromigration method (so-called Klemm method). The results have been presented as isotherms of cation internal mobilities versus equivalent fraction of NdCl3 for 1023, 1073 and 1123 K and have been compared with corresponding relationships for NaCl–NdCl3 and KCl–NdCl3 systems. It has been found that internal mobility of Nd3+ ions (as well as Li+) increases with decreasing concentration of NdCl3, contrary to KCl–NdCl3 and NaCl–NdCl3 systems for which Nd3+ internal mobility decreases or is nearly constant, respectively. The tendency that smaller alkali metal cation enhances internal mobility of trivalent ion (bLn) has been described with a simple equation: bLn=bLn0+a(1−yLnCl3)2, where bLn0 is the internal mobility of Ln3+ in molten LnCl3, yLnCl3yLnCl3 the equivalent fraction of LnCl3 and a parameter is the difference between internal mobility of Ln3+ cation in molten LnCl3 and internal mobility of this cation in infinitely diluted solution of LnCl3 in alkali metal chloride.