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Quantum Chemical Studies of the Hydration of Sr 2+ in Vacuum and Aqueous Solution
Author(s) -
Kerridge Andrew,
Kaltsoyannis Nikolas
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201003226
Subject(s) - solvation shell , solvation , aqueous solution , chemistry , density functional theory , quantum chemical , molecule , thermodynamics , entropy (arrow of time) , shell (structure) , computational chemistry , materials science , physics , organic chemistry , composite material
The geometric structures of gas‐phase Sr 2+ hydrates are calculated quantum chemically by using hybrid (B3LYP) and meta ‐GGA (TPSS) density functional theory, and a range of thermodynamic data (including sequential bond enthalpies, entropies and free energies for the reactions Sr 2+ (H 2 O) n −1 +H 2 O→Sr 2+ (H 2 O) n ) are shown to be in excellent agreement with experiment. When the number of coordinating water molecules exceeds six, such that water begins to occupy the second solvation shell, it is found that detailed analysis based on both geometrical and conformational entropy is required in order to confidently identify the experimentally observed structures. The significant increase in coordination number observed experimentally between the gas‐ and aqueous‐phase species is successfully reproduced, as is the first solvation shell geometry. Inaccurate second shell geometries imply that larger model systems may be required to achieve agreement with experiment. Candidate species for on‐going computational studies of the interaction of hydrated Sr 2+ with brucite surfaces have been identified.