Spectroscopic and Structural Characterization of Water-Shared Ion-Pairs in Aqueous Sodium and Lithium Hydroxide
| Autor: | Aria J. Bredt, Steven A. Corcelli, Dor Ben-Amotz, Denilson Mendes de Oliveira, Tierney C. Miller |
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| Rok vydání: | 2021 |
| Předmět: |
Range (particle radiation)
Aqueous solution 010304 chemical physics Sodium Inorganic chemistry chemistry.chemical_element 010402 general chemistry 01 natural sciences Lithium hydroxide 0104 chemical sciences Surfaces Coatings and Films Characterization (materials science) Ion chemistry.chemical_compound symbols.namesake chemistry 0103 physical sciences Materials Chemistry symbols Hydroxide Physics::Chemical Physics Physical and Theoretical Chemistry Raman spectroscopy |
| Zdroj: | The journal of physical chemistry. B. 125(5) |
| ISSN: | 1520-5207 |
| Popis: | The structures of the ion-pairs formed in aqueous NaOH and LiOH solutions are elucidated by combining Raman multivariate curve resolution (Raman-MCR) experiments and ab initio molecular dynamics (AIMD) simulations. The results extend prior findings to reveal that the initially formed ion-pairs are predominantly water-shared, with the hydroxide ion retaining its full first hydration-shell, while direct contact ion-pairing only becomes significant at higher concentrations. Our results confirm previous experiments and simulations indicating greater ion-pairing in aqueous LiOH than NaOH as well as at high temperatures. Our results further imply that NaOH and LiOH ion-pairing free energies have an approximately linear (rather than square-root) dependence on ion concentration (in the molar range), with positive enthalpies and entropies that increase with concentration, thus implying that water-mediated interactions enthalpically disfavor and entropically favor ion-pair formation. |
| Databáze: | OpenAIRE |
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