Group hydrated ions

A number of refinements and applications are in the literature. Corrections may be made for discreteness of charge [36] or the excluded volume of the hydrated ions [19, 37]. The effects of surface roughness on the electrical double layer have been treated by several groups [38-41] by means of perturbative expansions and numerical analysis. Several geometries have been treated, including two eccentric spheres such as found in encapsulated proteins or drugs [42], and biconcave disks with elastic membranes to model red blood cells [43]. The double-layer repulsion between two spheres has been a topic of much attention due to its importance in colloidal stability. A new numeri-... 

Water-soluble pAM neutral polymer interacts with ions of the solution through the complex formation between amide groups and hydrated ions. 

Furthermore it can be shown that besides the direct influence of hydrophilic and hydrophobic hydration on the conformation, the interaction of charged groups with ions is also strongly influenced by the hydration of the groups involved. Such studies were made largely by using relatively simple poly-a-aminoacids with ionogenic side chains as model substances. 

Hydration consists of the binding of water dipoles to ions or ionic groups, to dipoles, or polar groups. Hydration takes place in solid substances as well as in solution. 

Cevc, G. Watts, A. Marsh, D., Titration of the phase transition of phosphatidylserine bilayer membranes. Effects of pH, surface electrostatics, ion binding, and head group hydration. Biochemistry 20, 4955 -965 (1981). 

There are only few main group metal ion hydrates open to detailed mechanistic study of water exchange by NMR Be , Mg , Al" , Ga" and to a less extent, In" . They provide the opportunity to study the influence of size and charge on exchange rate constant and mechanism without the complicating effects of the variation of the electronic occupancy of the d-orbitals. All of the alkali ions as well as Ca , Sr, and Ba are very labile as a consequence of their relatively low surface charge density. However, indications on water exchange on Sr " can be obtained from... 

Much use has also been made of tunneling concepts in work on electron transfer from electrode to enzymes in solution, some of which adsorb on the electrode (Tarasevich, 1983). Most enzymes are huge in size (r > 50 A) compared with the hydrated ions usually considered. They contain a heme group that is a metal ion that must be reached by an electron if reduction is to occur. This would seem to introduce a hindrance to the development of the theoiy of enzyme electrochemistry. An electron... 

The electronegativity principle provides an explanation of the stability of hydrated ions of the iron-group transition elements with oxida-... 

The cations of Group 1 and 2 metals, and those of charge +1 from other groups, are such weak Lewis acids that the hydrated ions do not act as acids. 

Many of the d-block elements form characteristically colored solutions in water. For example, solid copper(II) chloride is brown and copper(II) bromide is black, but their aqueous solutions are both light blue. The blue color is caused by the hydrated copper(II) ions of composition Cu(H20)g]2+ that form when the solids dissolve. As the formula suggests, these hydrated ions have a specific composition they also have definite shapes and properties. They can be regarded as the outcome of a reaction in which the water molecules act as Lewis bases (electron pair donors, Section 2.13) and the Cu2+ ion acts as a Lewis acid (an electron pair acceptor). This type of Lewis acid-base reaction is characteristic of many cations of both main-group and d-block elements. 

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