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High-resolution Measurement of Contact Ion-pair Structures in Aqueous RbCl Solutions from the Simultaneous Corefinement of their Rb and Cl K-edge XAFS and XRD Spectra

Pham, Van-Thai LU and Fulton, John L. (2016) In Journal of Solution Chemistry 45(7). p.1061-1070
Abstract
In concentrated solutions of aqueous RbCl, all of the Rb+ and Cl– ions exist as contact ion pairs. This full structural assessment is derived from the refinement of three independent experimental measurements: the Rb and Cl K-edge X-ray absorption fine structure (XAFS) and the X-ray diffraction spectra (XRD). This simultaneous refinement of the XAFS and XRD data provides high accuracy since each method probes the structure of different local regions about the ions with high sensitivity. At high RbCl concentration (6 molﰆkg–1) the solution is dominated by Rb+–Cl– contact ion pairs yielding an average of 1.5 pairs at an Rb–Cl distance of 3.24 A ̊ . Upon formation of these ion pairs, approximately 1.1 waters molecules are displaced from the... (More)
In concentrated solutions of aqueous RbCl, all of the Rb+ and Cl– ions exist as contact ion pairs. This full structural assessment is derived from the refinement of three independent experimental measurements: the Rb and Cl K-edge X-ray absorption fine structure (XAFS) and the X-ray diffraction spectra (XRD). This simultaneous refinement of the XAFS and XRD data provides high accuracy since each method probes the structure of different local regions about the ions with high sensitivity. At high RbCl concentration (6 molﰆkg–1) the solution is dominated by Rb+–Cl– contact ion pairs yielding an average of 1.5 pairs at an Rb–Cl distance of 3.24 A ̊ . Upon formation of these ion pairs, approximately 1.1 waters molecules are displaced from the Rb? and 1.4 water molecules from Cl–. The hydration shells about both the cation and anion are also determined. These results greatly improve the understanding of monovalent ions and provide a basis for testing the Rb?–Cl– interaction potentials used in molecular dynamics (MD) simulation. (Less)
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author
and
publishing date
type
Contribution to journal
publication status
published
keywords
Aqueous RbCl, EXAFS, Ion hydration, Ion–pair, XADSR, XRD
in
Journal of Solution Chemistry
volume
45
issue
7
pages
10 pages
publisher
Springer
external identifiers
  • scopus:84975246759
ISSN
0095-9782
DOI
10.1007/s10953-016-0487-5
language
English
LU publication?
no
id
332ffda3-70a3-4d88-a21c-56d74220cbac
date added to LUP
2019-06-30 09:36:36
date last changed
2022-04-10 19:28:02
@article{332ffda3-70a3-4d88-a21c-56d74220cbac,
  abstract     = {{In concentrated solutions of aqueous RbCl, all of the Rb+ and Cl– ions exist as contact ion pairs. This full structural assessment is derived from the refinement of three independent experimental measurements: the Rb and Cl K-edge X-ray absorption fine structure (XAFS) and the X-ray diffraction spectra (XRD). This simultaneous refinement of the XAFS and XRD data provides high accuracy since each method probes the structure of different local regions about the ions with high sensitivity. At high RbCl concentration (6 molﰆkg–1) the solution is dominated by Rb+–Cl– contact ion pairs yielding an average of 1.5 pairs at an Rb–Cl distance of 3.24 A ̊ . Upon formation of these ion pairs, approximately 1.1 waters molecules are displaced from the Rb? and 1.4 water molecules from Cl–. The hydration shells about both the cation and anion are also determined. These results greatly improve the understanding of monovalent ions and provide a basis for testing the Rb?–Cl– interaction potentials used in molecular dynamics (MD) simulation.}},
  author       = {{Pham, Van-Thai and Fulton, John L.}},
  issn         = {{0095-9782}},
  keywords     = {{Aqueous RbCl; EXAFS; Ion hydration; Ion–pair; XADSR; XRD}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{7}},
  pages        = {{1061--1070}},
  publisher    = {{Springer}},
  series       = {{Journal of Solution Chemistry}},
  title        = {{High-resolution Measurement of Contact Ion-pair Structures in Aqueous RbCl Solutions from the Simultaneous Corefinement of their Rb and Cl K-edge XAFS and XRD Spectra}},
  url          = {{http://dx.doi.org/10.1007/s10953-016-0487-5}},
  doi          = {{10.1007/s10953-016-0487-5}},
  volume       = {{45}},
  year         = {{2016}},
}