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Title: Electrolyte layering at the calcite(104)-water interface indicated by Rb+- and Se(VI) K-edge resonant interface diffraction

Calcite–water interface reactions are of major importance in various environmental settings as well as in industrial applications. Here we present resonant interface diffraction results on the calcite(104)–aqueous solution interface, measured in solutions containing either 10 mmol L-1 RbCl or 0.5 mmol L-1 Se(VI). Results indicate that Rb+ ions enter the surface adsorbed water layers and adsorb at the calcite(104)–water interface in an inner-sphere fashion. A detailed analysis based on specular and off-specular resonant interface diffraction data reveals three distinct Rb+ adsorption species: one 1.2 Å above the surface, the second associated with surface adsorbed water molecules 3.2 Å above the surface, and the third adsorbed in an outer-sphere fashion 5.6 Å above the surface. A peak in resonant amplitude between L = 1.5 and L = 3.0 is interpreted as signal from a layered electrolyte structure. The presence of a layered electrolyte structure seems to be confirmed by data measured in the presence of Se(VI).
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Publication Date:
OSTI Identifier:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Chem. Chem. Phys.; Journal Volume: 16; Journal Issue: (25) ; 2014
Research Org:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Org:
Country of Publication:
United States