Ions, aqueous, properties

Polynuclear transition metal cyanides such as the well-known Prussian blue and its analogues with osmium and ruthenium have been intensely studied Prussian blue films on electrodes are formed as microcrystalline materials by the electrochemical reduction of FeFe(CN)g in aqueous solutionThey show two reversible redox reactions, and due to the intense color of the single oxidation states, they appear to be candidates for electrochromic displays Ion exchange properties in the reduced state are limited to certain ions having similar ionic radii. Thus, the reversible... 

A new water-soluble calix[4]arene-triacid-monoquinone (99) has been synthesized and its ion-binding properties in aqueous solution were investigated by means of voltammetry and UV-visible spectrophotometry. The electrochemical behaviour of (99) is dependent on the concentration of Ca + ion rather than that of other alkaline... 

As a result of the absence of A102 units in the crystalline lattice, Silicalite has no ion exchange properties. This characteristic makes Silicalite hydrophobic while zeolites are commonly used to extract water from organic substances, Silicalite selectively extracts organic materials from aqueous solutions (J)). 

Changes in mobile-phase components such as pH, ionic strength, and water content have been systematically studied [3,310,316,317]. These studies indicate that retention of basic analytes is mediated primarily by the cation-exchange properties of the silica [2]. Interestingly, it has been suggested from retention data of various pharmaceuticals that the retention mechanisms of silica with aqueous eluents and reversed-phase systems are similar [317,318]. Due to the ion-exchange properties of silica, mobile-phase pH adjustments are useful in changing the retention of ionic compounds. 

The surface properties of the aluminum oxide in aqueous solutions play an important role in the technology of dispersed system processing and utilization of wastes containing alumina oxides or hydroxides. The wide abundance and application of alumina oxide caused intensification of their investigations in colloid chemistry. Especially coagulation, flocculation, filtration and ion exchanging properties of the systems were examined. For all these processes, the electrical properties of the interface, that rule the accumulation and transportation of the charge, are very important. 

Through the investigation of various synthetic conditions, the actions of non-aqueous solvents, organic amines and F cations for product crystallization are further clarified. Moreover, the probable reaction mechanisms for the formations of the compounds were estimated. These mechanisms need to be proved or corrected via further investigation. Additionally, with cations located at the interspaces of the structures, the compounds will probably have some ion-exchange properties, researches about which are now in progress. 

Many properties of electrolytic solutions are additive functions of the properties of the respective ions this is at once evident from the fact that the chemical properties of a salt solution are those of its constituent ions. For example, potassium chloride in solution has no chemical reactions which are characteristic of the compound itself, but only those of potassium and chloride ions. These properties are possessed equally by almost all potassium salts and all chlorides, respectively. Similarly, the characteristic chemical properties of acids and alkalis, in aqueous solution, are those of hydrogen and hydroxyl ions, respectively. Certain physical properties of electrolytes are also additive in nature the most outstanding example is the electrical conductance at infinite dilution. It will be seen in Chap. II that conductance values can be ascribed to all ions, and the appropriate conductance of any electrolyte is equal to the sum of the values for the individual ions. The densities of electrolytic solutions have also been found to be additive functions of the properties of the constituent ions. The catalytic effects of various acids and bases, and of mixtures with their salts, can be accounted for by associating a definite catalytic coefl5.cient with each type of ion since undissociated molecules often have appreciable catalytic properties due allowance must be made for their contribution. 

For every aluminum atom in the lattice, a fixed negative charge results. This negative charge is counterbalanced by mobile cations, typically alkaline or alkaline-earth cations. In contact with aqueous solutions, these mobile cations can easily be exchanged for other cations (metal cations, cationic complexes) of appropriate dimensions, thus determining the remarkable ion exchange properties of zeolites. 

The chemistry of natural zeolites may have important effects on their ion exchange properties, mainly in terms of selectivity. It is well known that selectivity is a function of various parameters, depending on (1) framework topology, (2) ion size and shape, (3) charge density on the anionic framework, (4) ion valence and (5) electrolyte concentration in the aqueous phase [51]. Within the same zeolite type, the variation of the framework composition (in practice, Si/Al ratio) and therefore of the framework charge density, affects the cation selectivity [52], as it has experimentally been proven for phillipsitc [53]. It is improper, stricto sensu, to compare with each other, in terms of selectivity behaviour, different zeolites having... 

In summary, actinides in the oxidation stage M(III) form trivalent ions in aqueous solution with chemical properties similar to those of the trivalent tare earths, e.g., lanthanum. The M(IV) actinides form tetravalent ions with properties characteristic of Th. The M(V) actinides form MOj" ions, and the M(VI) form ions whose properties are characteristic of The... 

There are several complete compilations of the literature concerning zirconium and hafnium that take the reader up to about 1960 62, 344, 420, 558). Since then several reviews of more limited scope have been published, one on the structural aspects of zirconium chemistry 116), and others on the separation of zirconium and hafnium 578), aqueous chemistry 234, 533), and ion-exchange properties of zirconium compounds 29). In general, the data in the present review are drawn from publications since 1960, although references to earlier work are included where necessary to complete the picture. 

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