Isothermal compressibility, internal pressure studies of aqueous rare earth nitrate solutions at 298.15 K: An attempt to estimate ionic radii and understand inner– and outer–sphere exchange water structural interactions

• Published in: Journal of molecular liquids Vol. 399; p. 124361
• Main Authors: Tomar, Preeti A., Shaikh, Vasim R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2024
• Subjects: Hydration number; Internal pressure; Ionic radii; Ion–pair and complex formation; Isothermal compressibility; Tammann–Tait–Gibson equation of state; Tammann–Tait–Gibson equation of state; Isothermal compressibility; Ion–pair and complex formation; Ionic radii; Hydration number; Internal pressure
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2024.124361

Variation of internal pressure (Pi) as a function of cation radius for rare earth nitrate salts/chloride salts in aqueous solutions at 298.15 K. The plots are made for solution of 0.36 m.
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•Variation of βT as a function of molality of rare earth nitrates in water are reported.•Internal pressure variation for rare earth nitrates in water are studied.•Electrostriction, intrinsic volume and ionic radii for rare earth cations and have been calculated.•The two series affect is observed for ionic radii and internal pressure.
In this communication, we report our analysis and results concerning the determination of ionic radii in aqueous solution phase for Lanthanum (La+3), Neodymium (Nd+3), Erbium (Er+3) and Ytterbium (Yb+3) ions in presence of nitrate (NO3-) anion at 298.15 K. The literature data for density, adiabatic compressibility, and specific heat capacity of solutions at constant pressure have been used to compute isothermal compressibility, internal pressure of solutions in limiting concentration range. The apparent molar isothermal compressibility of electrolytes and hydration numbers have been obtained. The electrostriction for rare earth cations and intrinsic volumes have been calculated using thermodynamic equations. The ionic radii of cations have been obtained using the ionic partial molar volume data of NO3- ions and the results are compared with those obtained for rare earth chlorides. The two series affect is also observed for ionic radii and internal pressure. The results have been explained on the basis of water structural effects due to electrostatic field and water dipole interaction between the inner– and outer–sphere water exchange reaction.