Evaluation of individual ionic partial molar volumes in aqueous solutions

Molar volumes of LiI in H2O and D2O solutions; Structural hydration interactions

“…figure 2. They could be fitted over both concentration ranges within experimental errors to the form of the (''extended") Masson equation (4), see reference [5], [6]. As a consequence, these are included in the fits.…”

“…increases with increasing temperature [6] and the Li + is ''positively" hydrated (decreased solvent activity), while the I À is ''negatively" hydrated (increased solvent activity [6,7]), their overall influences on the activities of the isotopic solvents should be small and/or well compensated.…”

“…Correspondingly, Li + has the largest, the I À the smallest positively hydrated hydration sphere, which is apparent among others in their (single ionic) hydrodynamic hydration volumes [6], calculated from the kinetic (Stokes) ionic radii [9]. Such asymmetry between the hydration capabilities of the cation and anion is characteristic for solutions, where with increasing concentration the structural hydration interactions result in a ''mutual saltingout" process, see reference [8].…”

“…As we pointed out in our preceding MVIE study [1], the inner hydration structure of the Li + should be similar to that of the hydronium ion, H 9 O þ 4 , see reference [8], both having unique negative expansibilities. Due to the multilayer hydrogen-bonded primary hydration sphere, neither V o 2 (Li + ) [6] nor its solvent isotope effect [1] corresponds to those of the other alkali cations.…”