EXAFS investigation of the second hydration shell of metal cations in dilute aqueous solutions

✍ Scribed by A. Muñoz-Páez; S. Díaz; P.J. Pérez; M.E. Martín-Zamora; J.M. Martínez; R.R. Pappalardo; E.Sánchez Marcos

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 175 KB
• Volume: 208-209
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)00856-q

✦ Synopsis

EXAFS spectra of aqueous dilute solutions (0.1 M) containing Cr 3 ÷, Rh 3 +, Ga 3 + and Zn 2 + ions are presented. From the EXAFS fit parameters it is deduced that always the first hydration shell is formed by six water molecules with M-O distances between 1.95 and 2.06/~. A second hydration shell is also observed in all cases, although the amplitude of this contribution increases with the stability of aquocomplexes. This can be quantified by the correlation between the Debye-Waller factors for the first and second hydration shells, and the first-shell water release constants of the hydrated cations.