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Densities and Apparent Molar Volumes of Rubidium and Cesium Triflates to High Concentrations in Aqueous Solution at Temperatures from 293.15 to 343.15 K

Hnědkovský, L. and Hefter, G. (2022) Densities and Apparent Molar Volumes of Rubidium and Cesium Triflates to High Concentrations in Aqueous Solution at Temperatures from 293.15 to 343.15 K. Journal of Chemical & Engineering Data, 67 (1). pp. 123-131.

Link to Published Version: https://doi.org/10.1021/acs.jced.1c00837
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Abstract

Densities of aqueous solutions of rubidium triflate (RbTf) and cesium triflate (CsTf), where Tf– is the trifluoromethanesulfonate ion (CF3SO3–), have been measured by vibrating-tube densimetry at temperatures from 293.15 to 343.15 K at 5 K intervals. Concentrations ranged from 0.03 to 5.0 mol·kg–1 for RbTf and from 0.02 to 3.9 mol·kg–1 for CsTf. No volumetric data for either salt appear to have been published previously. Apparent molar volumes (Vϕ) calculated from the densities were well modeled with Pitzer equations. Standard partial molar volumes, Vo, for RbTf(aq) and CsTf(aq) were determined by extrapolation of the Pitzer fits to infinite dilution. Isobaric coefficients of thermal expansion (expansivities), α, derived from the temperature dependence of the densities, increased with concentration, especially at lower T, consistent with the solvent-structure-breaking character of their component ions. Combination of the present Vo values with a common extra-thermodynamic assumption and relevant literature data provided ionic volumes, Vo(Rb+,aq) and Vo(Cs+,aq), that show more realistic temperature dependences than previous estimates.

Item Type: Journal Article
Murdoch Affiliation(s): Mathematics, Statistics, Chemistry and Physics
Publisher: American Chemical Society
Copyright: © 2022 American Chemical Society
URI: http://researchrepository.murdoch.edu.au/id/eprint/63669
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