Hydration and ion association of La3+ and Eu3+ salts in aqueous solution. Issue 13 (15th March 2018)

• Record Type: Journal Article
• Authors: Friesen, Sergej; Krickl, Sebastian; Luger, Magdalena; Nazet, Andreas; Hefter, Glenn; Buchner, Richard
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 13(2018)
• Page Start: 8812
• Page End: 8821
• Publication Date: 2018-03-15
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c8cp00248g
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Lanthanide ions affect water out to the third shell and form double solvent-separated and solvent-shared ion pairs. Abstract : Aqueous solutions of five lanthanide salts: LaCl3, La(NO3 )3, La2 (SO4 )3, Eu(NO3 )3 and Eu2 (SO4 )3 have been studied at 25 °C by dielectric relaxation spectroscopy over the frequency range 0.05 ≤ ν /GHz ≤ 89. Detailed analysis of the solvent-related modes located at higher frequencies showed that both La 3+ and Eu 3+ are strongly hydrated, even including partial formation of a third hydration shell similar to that of Al 3+ (aq). Up to two solute-related modes could be detected at lower frequencies, due to the formation of various types of 1 : 1 ion pairs (IPs). All five salts showed modest levels of association in the order Cl − < NO3 − ≪ SO4 2−, mostly in the form of double-solvent-separated IPs with small amounts of solvent-shared IPs. Overall association constants, , calculated from the stepwise IP formation constants were consistent with literature values.