Journal of Solution Chemistry

, Volume 39, Issue 12, pp 1888–1897 | Cite as

Spectrophotometric and Calorimetric Studies of Np(V) Complexation with Acetate at Various Temperatures from T=283 to 343 K

  • Linfeng Rao
  • Guoxin Tian
  • Thandankorai G. Srinivasan
  • PierLuigi Zanonato
  • Plinio Di Bernardo


Spectrophotometric titrations were performed to identify the Np(V)/acetate complex and determine the equilibrium constants at various temperatures (T=283 to 343 K) and at the ionic strength 1.05 mol⋅kg−1. The enthalpies of complexation at the corresponding temperatures were determined by microcalorimetric titrations. Results show that the complexation of Np(V) with acetate is weak but strengthens as the temperature increases. The complexation reaction is endothermic and entropy driven. The enhancement of complexation at higher temperatures is primarily due to the increasingly larger entropy gain when the solvent molecules are released from the highly-ordered solvation spheres of \(\mathrm{NpO}_{2}^{+}\) and acetate to the bulk solvent where the degree of disorder is higher at higher temperatures.


Neptunium Acetate Complexation Temperature effect 


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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Linfeng Rao
    • 1
  • Guoxin Tian
    • 1
  • Thandankorai G. Srinivasan
    • 1
  • PierLuigi Zanonato
    • 2
  • Plinio Di Bernardo
    • 2
  1. 1.Lawrence Berkeley National LaboratoryBerkeleyUSA
  2. 2.Dipartimento di Scienze ChimicheUniversità di PadovaPadovaItaly

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