title: Quantized hydration energies of ions and structure of hydration shell from the experimental gas-phase data.
abstract: With previous data on alkali metal and halide ions included [Rais, J.; Okada, T. Anal. Sci. 2006, 22, 533], we analyzed rather broad data on ionic hydration from the point of view of gaseous cluster energetics. We have now added alkaline earth cations, Zn(2+), H(+), OH(-), Cu(+), Ag(+), Bi(+), Pb(+), and alkylammonium cations. The present analysis revealed the octa-coordinated nature of alkaline earth cations, which is not fully pronounced for Be(2+) and Zn(2+), existence of Eigen protonium complex, which is trigonally hydrated, and particular property of the first OH-, H(2)O cluster. Whereas these findings are generally in accordance with theoretical model calculation studies, we have foreseen in addition tetrahedral hydration for halide anions and Rb(+) and Cs(+), as well as for alkylammonium ions. The obtained picture of the quantized solvation of ions is mirrored in the ionization potentials of outer electrons of pertinent atoms. This is a second independent phenomenon, and together, they invoked a common pattern formation ("Aufbau") obeying tetra- and octa-coordinated principles.
authors.affiliation: Nuclear Research Institute plc, ReZ, 25068 ReZ, Czech Republic.
authors.forename: Jirí
authors.initials: J
authors.lastname: Rais
authors.forename: Tatsuhiro
authors.initials: T
authors.lastname: Okada