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Homolytic versus Heterolytic Dissociation of Alkalimetal Halides: The Effect of Microsolvation
Author(s) -
Osuna Sílvia,
Swart Marcel,
Baerends Evert Jan,
Bickelhaupt F. Matthias,
Solà Miquel
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900480
Subject(s) - heterolysis , homolysis , dissociation (chemistry) , chemistry , halide , diatomic molecule , bond dissociation energy , photochemistry , molecule , inorganic chemistry , radical , catalysis , organic chemistry
Herein we report density functional calculations of homolytic and heterolytic dissociation energies of the diatomic alkalimetal halides MX (M=Li, Na, K, Rb, and Cs and X=F, Cl, Br, I, and At) and their corresponding microsolvated structures MX⋅(H 2 O) n ( n =1 to 4). Our results show that the homolytic dissociation energy of the MX⋅(H 2 O) n species increases with the number of water molecules involved in the microsolvated salts. On the other hand, the heterolytic dissociation energy follows exactly the opposite trend. As a result, while for the isolated diatomic alkalimetal halides, homolytic dissociation is always favored over heterolytic dissociation, the latter is preferred for CsF and CsCl already for n =2, and for n =4 it is the preferential mode of dissociation for more than half of the species studied.