Zusammenfassung
The results of dielectric relaxation experiments on solutions of LiClO4, NaClO4 and Bu4NClO4 in N,N-dimethylfonnamide (DNIF), and N,N-dimethylacetamide (DMA), performed at 25 degrees C in the frequency range 0.2 <= v/GHz <= 89 are presented. For all electrolytes, a solute relaxation process due to ion pairs is observed in addition to the solvent relaxation. The alkali salts form predominantly ...
Zusammenfassung
The results of dielectric relaxation experiments on solutions of LiClO4, NaClO4 and Bu4NClO4 in N,N-dimethylfonnamide (DNIF), and N,N-dimethylacetamide (DMA), performed at 25 degrees C in the frequency range 0.2 <= v/GHz <= 89 are presented. For all electrolytes, a solute relaxation process due to ion pairs is observed in addition to the solvent relaxation. The alkali salts form predominantly solvent-shared ion pairs in DNIF and DMA, whereas contact ion pairs are observed for Bu4NClO4 In all cases, the rate of ion-pair formation is nearly diffusion controlled. Effective solvation numbers were deduced from the solvent dispersion amplitude. Data suggest that the anion-solvent interactions are weak, whereas the alkali ions form a well-defined primary solvation shell. Interestingly, irrotational bonding of solvent molecules by Bu4N+ is observed, possibly due to steric interactions. (c) 2004 Elsevier B.V. All rights reserved.
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