A different view of structure-making and structure-breaking in alkali halide aqueous solutions through x-ray absorption spectroscopy
Number of Authors: 6
2014 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 140, no 24, 244506- p.Article in journal (Refereed) Published
X-ray absorption spectroscopy measured in transmission mode was used to study the effect of alkali and halide ions on the hydrogen-bonding (H-bonding) network of water. Cl- and Br- are shown to have insignificant effect on the structure of water while I-locally weakens the H-bonding, as indicated by a sharp increase of the main-edge feature in the x-ray absorption spectra. All alkali cations act as structure-breakers in water, weakening the H-bonding network. The spectral changes are similar to spectra of high density ices where the 2nd shell has collapsed due to a break-down of the tetrahedral structures, although here, around the ions, the breakdown of the local tetrahedrality is rather due to non-directional H-bonding to the larger anions. In addition, results from temperature-dependent x-ray Raman scattering measurements of NaCl solution confirm the H-bond breaking effect of Na+ and the effect on the liquid as similar to an increase in temperature.
Place, publisher, year, edition, pages
2014. Vol. 140, no 24, 244506- p.
IdentifiersURN: urn:nbn:se:su:diva-106752DOI: 10.1063/1.4881600ISI: 000338634200044OAI: oai:DiVA.org:su-106752DiVA: diva2:738930