Rate of water exchange from hydrated magnesium ion

Abstract

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Molecular simulation of the diffusion of uranyl carbonate species in aqueous solution

“…For the alkaline-earth cations, some experimental data are available for Mg 2+ and Ca 2+ . Although the residence time of water in the magnesium hydration shell is longer than the timescale of the simulation and therefore no exchange was observed during the entire MD run, previous work (Kerisit and Parker, 2004) using constrained MD simulations and the same magnesium-water potential as used in this work, albeit with a different water model, gave excellent agreement with the experimental data of Bleuzen et al (1997) (6.7 ± 0.2 Â 10 5 s À1 ) and Neely and Connick (1970) (5.3 ± 0.3 Â 10 5 s À1 ). For calcium, a quasi-elastic neutron scattering (QENS) study (Salmon et al, 1987) reported a water residence time of less than 100 ps.…”

Kinetics and Equilibria of Nickel(II)−Schiff Base Adducts Formation

“…The latter values compare quite satisfactorily with the activation parameters reported for solvent exchange: [17] ∆H ϶ ϭ 60.8 Ϯ 1.1 kJ mol Ϫ1 and ∆S ϶ ϭ 25.8 J Ϯ 2.8 J mol Ϫ1 K Ϫ1 , thus confirming a dissociative mechanism.…”

“…stant of acetonitrile exchange [16] between the nickel(II) cations and the bulk solvent, and f ϭ 3/4 is a statistical factor taking into account the number of solvent molecules in the outer-sphere complex competing with the entering ligand. [17] The theoretical K 0 values derived from the electrostatic theory, see Table 2, as well as from theoretical calculations, vide infra, were in excellent agreement. Table 2.…”

Na-Montmorillonite Edge Structure and Surface Complexes: An Atomistic Perspective

“…With this additional perspective, the first peak of the Mg sol -Ow RDF reproduces the first cluster distance, and the first minimum of the RDF encompasses the distance of the second cluster [ Table 3: r peak (Mg sol -O) = 2.52 Å]. The water ligands associated with Mg sol were not exchanged with the bulk phase during the timescale of our classical MD trajectory, a result consistent with the slow exchange of first shell water molecules from hydrated Mg ions (average residence time: 1-2 µs [57,58]). The Mg pbc -O pair distribution is indistinguishable from the Mg-O pairs in bulk.…”