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Determination of the Solubility of Rhabdophanes LnPO 4 ·0.667H 2 O (Ln = La to Dy)
Author(s) -
Gausse Clémence,
Szenknect Stéphanie,
Qin Dan Wen,
Mesbah Adel,
Clavier Nicolas,
Neumeier Stefan,
Bosbach Dirk,
Dacheux Nicolas
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201600517
Subject(s) - chemistry , solubility , lanthanide , gibbs free energy , atmospheric temperature range , standard enthalpy of formation , analytical chemistry (journal) , thermodynamics , chromatography , organic chemistry , ion , physics
A systematic study of the solubility of the rhabdophanes LnPO 4 · 0.667H 2 O (Ln = La–Dy) was performed through oversaturation and undersaturation experiments at different temperatures (298–363 K) to demonstrate the reversibility of the equilibria. The structure of the neoformed phase was controlled carefully over the entire temperature range to enable the unambiguous attribution of the solubility products and the derived thermodynamic data to the rhabdophane phases. The log K ° s,0 (298 K) values for LnPO 4 · 0.667H 2 O ranged from –25.6 ± 0.8 (Pr) to –24.9 ± 1.7 (Eu), and the minimum values were for Pr to Sm, whereas the Δ f G ° values at 298 K varied between (–1984 ± 2) and (–2004 ± 2) kJ mol –1 whatever the lanthanide element considered, except for Eu‐rhabdophane, which presented the highest Gibbs energy of formation [(–1896 ± 2) kJ mol –1 ]. From the solubility data obtained at various temperatures, the enthalpies of formation of the rhabdophanes Δ f H ° were found to be (–2151 ± 13) to (–2130 ± 12) kJ mol –1 , excepted for that of Eu, which reached (–2057 ± 9) kJ mol –1 .