Internal Cation Mobilities in the Molten Systems (Li-Na)NO₃ and (Na-Cs)NO₃

Abstract

For the molten salt systems (Li-Na)N03 and (Na-Cs)N03, relative differences of intei'nal mobilities have been measured with the Klemm method. The internal mobilities, b, are calculated from these data and the available conductivity data. In the mixtures of the former system, &xa is always greater thanIn the latter system, the Chemla crossing point occurs. It is found that bu and &xa in the binary alkali nitrate systems so far investigated are well expressed, except at small molar volumes, by b = {^4/(F-F 0 )} exp(-E/RT) with constant A and E, where V is the molar volume and F° a constant for bu and nearly a constant for The values of bes at equal concentrations of CSNO3 in the systems (Li-Cs)N03 and (Na-Cs)NOs are practically equal. The internal mobilities obtained are discussed in terms of free space, mutual ionic attraction and thermal agitation.

Some Properties of Molten KCl at High Density Studied by MD Simulation

“…This value would depend on pair potentials implicitly including the concept of ionic size, moveability of coions, and temperature; this would be different from that for the self-diffusion. The existence of such an optimal volume has been suggested also for the internal mobilities from the experimental results of molten alkali nitrate mixtures [3]. For pure KCl in the present case, where the sizes of both ions are rather large, in other words, the attraction between cation and anion is not so strong, the optimal molar volume is expected to be larger than that at normal density, and hence the SEV decreases at higher density.…”

“…On the basis of the results of molecular dynamics simulation [1] as well as of experiments [2,3], we have assumed that in transport phenomena of ionic melts such as diffusion and electric conduction, interactions between cation and anion and the relative volume of free space compared with the ionic size are the dominant factors. One way for elucidating the effect of the free-space on transport phenomena is to measure the properties under high pressure.…”

Internal Cation Mobilities in the Molten Binary Systems (Li, Na)Cl and (Na, K)Cl

“…The profiles of the isotherms for (Li, Na)Cl are similar to those of (Li, Na)N0 3 [6] in that the larger cation is more mobile than the smaller one in the whole concentration and temperature range. The sharp increase in b u and b Na with increasing concentration of LiCl is due to the sharp increase in the number density of the Cl~ ions.…”

“…Especially (Na, K)N0 3 shows the Chemla effect [5]. In (Li, Na)N0 3 the mobility of Na + is throughout larger than that of Li + [6].…”

Internal Mobilities in the Binary Molten System (Na, TI)NO3

“…In all these systems, in a certain range of concentration and temperature the Chemla effect was observed, i. e., the mobility of the larger cation is greater than that of the smaller one. Further, we have found that, when Coulombic interaction between the cations and anions is the predominant factor influencing the cationic mobilities, the internal mobilities b are well expressed by [3,4]:…”