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Title: Countercations Control Local Specific Bonding Interactions and Nucleation Mechanisms in Concentrated Water-in-Salt Solutions

Abstract

One of the continuing challenges presented in aqueous salt solutions is to understand ion association reactions driving dynamic demixing from solvation, complexation and solute clustering. The problems understanding this phenomenon are exacerbated in the highly-concentrated water-in-salt electrolytes, where the deficiency of water leads to a dramatic retardation of solvating water and formation of extended solvent-solute clustering networks. By probing microscopic dynamics of water and prenucleation clusters using quasi-elastic neutron scattering and proton nuclear magnetic resonance spectroscopy, we observed contrasting mechanistic specifics of ion-water mobilities in highly-concentrated Na+- vs. K+-based aluminate solutions (diffusion coefficients of 0.2 vs. 2.6?10-10m2s-1 at 293 K, respectively). The magnitude of the differences is far beyond the kosmotropic (Na+) and chaotropic (K+) effects typically understood at low ionic concentrations. The distinct crystallization mechanisms observed in analogous deuterated systems further imply that different prenucleation cluster dynamics and network packing morphologies can either frustrate or promote crystallization, as described by non-classical nucleation theory.

Authors:
 [1]; ORCiD logo [2];  [3];  [3];  [3];  [2]
  1. OAK RIDGE NATIONAL LAB
  2. BATTELLE (PACIFIC NW LAB)
  3. Oak Ridge National Laboratory
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1567252
Report Number(s):
PNNL-SA-142833
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 10; Journal Issue: 12
Country of Publication:
United States
Language:
English

Citation Formats

Wang, Hsiu-Wen, Graham, Trenton R., Mamontov, Eugene, Page, Katherine, Stack, Andrew G., and Pearce, Carolyn I. Countercations Control Local Specific Bonding Interactions and Nucleation Mechanisms in Concentrated Water-in-Salt Solutions. United States: N. p., 2019. Web. doi:10.1021/acs.jpclett.9b01416.
Wang, Hsiu-Wen, Graham, Trenton R., Mamontov, Eugene, Page, Katherine, Stack, Andrew G., & Pearce, Carolyn I. Countercations Control Local Specific Bonding Interactions and Nucleation Mechanisms in Concentrated Water-in-Salt Solutions. United States. doi:10.1021/acs.jpclett.9b01416.
Wang, Hsiu-Wen, Graham, Trenton R., Mamontov, Eugene, Page, Katherine, Stack, Andrew G., and Pearce, Carolyn I. Thu . "Countercations Control Local Specific Bonding Interactions and Nucleation Mechanisms in Concentrated Water-in-Salt Solutions". United States. doi:10.1021/acs.jpclett.9b01416.
@article{osti_1567252,
title = {Countercations Control Local Specific Bonding Interactions and Nucleation Mechanisms in Concentrated Water-in-Salt Solutions},
author = {Wang, Hsiu-Wen and Graham, Trenton R. and Mamontov, Eugene and Page, Katherine and Stack, Andrew G. and Pearce, Carolyn I.},
abstractNote = {One of the continuing challenges presented in aqueous salt solutions is to understand ion association reactions driving dynamic demixing from solvation, complexation and solute clustering. The problems understanding this phenomenon are exacerbated in the highly-concentrated water-in-salt electrolytes, where the deficiency of water leads to a dramatic retardation of solvating water and formation of extended solvent-solute clustering networks. By probing microscopic dynamics of water and prenucleation clusters using quasi-elastic neutron scattering and proton nuclear magnetic resonance spectroscopy, we observed contrasting mechanistic specifics of ion-water mobilities in highly-concentrated Na+- vs. K+-based aluminate solutions (diffusion coefficients of 0.2 vs. 2.6?10-10m2s-1 at 293 K, respectively). The magnitude of the differences is far beyond the kosmotropic (Na+) and chaotropic (K+) effects typically understood at low ionic concentrations. The distinct crystallization mechanisms observed in analogous deuterated systems further imply that different prenucleation cluster dynamics and network packing morphologies can either frustrate or promote crystallization, as described by non-classical nucleation theory.},
doi = {10.1021/acs.jpclett.9b01416},
journal = {Journal of Physical Chemistry Letters},
number = 12,
volume = 10,
place = {United States},
year = {2019},
month = {6}
}