The expression for the Gibbs energy of solvation for simple 1-1 electrolytes within the mean spherical approximation has been fitted to data for 20 alkali metal halides in water. In performing this fit, one needs to assume a radius for each ion, the Pauling values often having been chosen in the past. The MSA parameters appear as corrections to these radii and are different for cations and anions. Two sets of ionic radii were considered, the Pauling values from crystallographic data and values based on X-ray diffraction results obtained in aqueous solutions. Excellent fits between theory and experiment were obtained, the results with the latter set of radii being preferred. This analysis provides an extrathermodynamic route to single ion solvation free energies and yields results which are very close to the real free energy of solvation measured by Randles.
Ions are ubiquitous in chemical, technological, ecological and biological processes. Characterizing their role in these processes in the first place requires the evaluation of the thermodynamic parameters associated with the solvation of a given ion. However, due to the constraint of electroneutrality, the involvement of surface effects and the ambiguous connection between microscopic and macroscopic descriptions, the determination of single-ion solvation properties via both experimental and theoretical approaches has turned out to be a very difficult and highly controversial problem. This unique book provides an up-to-date, compact and consistent account of the research field of single-ion solvation thermodynamics that has over one hundred years of history and still remains largely unsolved. By reviewing the various approaches employed to date, establishing the relevant connections between single-ion thermodynamics and electrochemistry, resolving conceptual ambiguities, and giving an exhaustive data compilation (in the context of alkali and halide hydration), this book provides a consistent synthesis, in depth understanding and clarification of a large and sometimes very confusing research field. The book is primarily aimed at researchers (professors, postgraduates, graduates, and industrial researchers) concerned with processes involving ionic solvation properties (these are ubiquitous, eg. in physical/organic/analytical chemistry, electrochemistry, biochemistry, pharmacology, geology, and ecology). Because of the concept definitions and data compilations it contains, it is also a useful reference book to have in a university library. Finally, it may be of general interest to anyone wanting to learn more about ions and solvation. Key features: - discusses both experimental and theoretical approaches, and establishes the connection between them - provides both an account of the past research (covering over one hundred years) and a discussion of current directions (in particular on the theoretical side) - involves a comprehensive reference list of over 2000 citations - employs a very consistent notation (including table of symbols and unambiguous definitions of all introduced quantities) - provides a discussion and clarification of ambiguous concepts (ie. concepts that have not been defined clearly, or have been defined differently by different authors, leading to confusion in past literature) - encompasses an exhaustive data compilation (in the restricted context of alkali and halide hydration), along with recommended values (after critical analysis of this literature data) - is illustrated by a number of synoptic colour figures, that will help the reader to grasp the connections between different concepts in one single picture
The entropy of solvation of monoatomic ions in polar solvents is considered within the context of the mean spherical approximation which is used to estimate the experimentally observed quantities in 15 different polar solvents. The role of ion-dipole interactions in determining both the Gibbs energy and entropy of solvation is assessed. It is shown that the temperature variation of the polarization parameter, which characterizes short-range electrostatic interactions, plays an important role in determining the magnitude of the entropy. Not only does this temperature coefficient depend on whether the ion is a cation or an anion, but also on the charge on the ion. The model developed here, together with the parameters extracted from experimental data for monoatomic ions, is applied to estimate the entropic change associated with a simple spherical redox system, namely, ferrocenium cation-ferrocene, which has been used as a model reaction for considering solvent effects on thermodynamic parameters.
Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
In order to quantitatively predict the chemical reactions that hazardous materials may undergo in the environment, it is necessary to know the relative stabilities of the compounds and complexes that may be found under certain conditions. This type of calculations may be done using consistent chemical thermodynamic data, such as those contained in this book for inorganic compounds and complexes of nickel. * Fully detailed authoritative critical review of literature.* Integrated into a comprehensive and consistent database for waste management applications.* CD ROM version.
The chapters making up this volume had originally been planned to form part of a single volume covering solid hydrates and aqueous solutions of simple molecules and ions. However, during the preparation of the manu scripts it became apparent that such a volume would turn out to be very unwieldy and I reluctantly decided to recommend the publication of sepa rate volumes. The most sensible way of dividing the subject matter seemed to lie in the separation of simple ionic solutions. The emphasis in the present volume is placed on ion-solvent effects, since a number of excellent texts cover the more general aspects of electrolyte solutions, based on the classical theories of Debye, Huckel, On sager, and Fuoss. It is interesting to speculate as to when a theory becomes "classical." Perhaps this occurs when it has become well known, well liked, and much adapted. The above-mentioned theories of ionic equilibria and transport certainly fulfill these criteria. There comes a time when the refinements and modifications can no longer be related to physical significance and can no longer hide the fact that certain fundamental assumptions made in the development of the theory are untenable, especially in the light of information obtained from the application of sophisticated molecular and thermodynamic techniques.
