The Hydration of Lanthanide-Chloride Salts : A Quantum Chemical and Classical Molecular Dynamics Simulation Study

Cesar Beuchat (1) , Daniel Hagberg (1) , Riccardo Spezia (2) , Laura Gagliardi (3)

1 UNIGE - Université de Genève = University of Geneva
2 LAMBE - Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement
3 UMN - University of Minnesota [Twin Cities]

We present the results of a quantum chemical and classical molecular dynamics simulation study of some solutions containing chloride salts of La³⁺, Gd³⁺, and Er³⁺ at various concentrations (from 0.05 to 5 M), with the purpose of understanding their structure and dynamics and analyzing how the coordination varies along the lanthanide series. In the La−Cl case, nine water molecules surround the central La³⁺ cation in the first solvation shell, and chloride is present only in the second shell for all solutions but the most concentrated one (5 M). In the Gd³⁺ case, the coordination number is ∼8.6 for the two lowest concentrations (0.05 and 0.1 M), and then it decreases rapidly. In the Er³⁺ case, the coordination number is 7.4 for the two lowest concentrations (0.05 and 0.1 M), and then it decreases. The counterion Cl⁻ is not present in the first solvation shell in the La³⁺ case for most of the solutions, but it becomes progressively closer to the central cation in the Gd³⁺ and Er³⁺ cases, even at low concentrations.

Domaines: Chimie théorique et/ou physique; Chimie-Physique [physics.chem-ph]

Cesar Beuchat, Daniel Hagberg, Riccardo Spezia, Laura Gagliardi. The Hydration of Lanthanide-Chloride Salts : A Quantum Chemical and Classical Molecular Dynamics Simulation Study. Journal of Physical Chemistry B, 2010, 114 (47), pp.15590-15597. ⟨10.1021/jp105590h⟩. ⟨hal-00616980⟩