MOLAR VOLUME VARIATION AND IONIC-CONDUCTION IN MOLTEN SMCL3-NACL, SMCL3-KCL AND SMCL3-CACL2 SYSTEMS

Molar volume, V-m, and electrical conductivity, kappa, of molten SmCl3 -NaCl, SmCl3-KCl and SmCl3-CaCl2 systems were measured by dilatometry and a conventional a.c. technique, respectively. The molar conductivit ies (Lambda) were evaluated using the data of molar volume and conduct ivity. The ii values of molten mixtures of SmCl3 with NaCl, KCl or CaC l2 suggested that the existence of dimeric or more polymeric complex a nions might be presumed in the melt as was the case in a series of mol ten rare earth chlorides. Additionally, the Lambda values of molten ra re earth chlorides appeared to be affected qualitatively by the cation ic radii and the types of linkage, that is, corner-or edge-sharing of octahedral units in melts. The Lambda values of molten SmCl3-NaCl and SmCl3-KCl systems increased with decreasing SmCl3 concentration, x, an d in the range of x>0.25 the increment in Lambda to x was much smaller than that in the range of x<0.25. As for molten SmCl2-CaCl2 system, t he Lambda values increased almost linearly with decreasing SmCl3 conce ntration all over the range. (C) 1997 Elsevier Science S.A.