Salts ionic diameter

We give in Table XXIV the salts ordered in increasing sum of the ionic diameter and compare also the solubility in water. As can be derived from the Table, there is no relationship between the solubility of the salts in water and the taste. Molecular weights show a certain parallel with increasing molecular weight the salts became bitter. 

An exception is KBr, which is bitter and salty, but according to the molecular weight should only be salty. A clear relation, however, exists between the sum of the ionic diameter of a salt and its bitterness. From LiCl with 4.98 X to RbCl with 6.56 X the salty taste dominates. KBr with 6.58 X is salty and bitter and from RbBr with 6.86 X to Csl with 7.74 X the bitter taste dominates. It should be mentioned that MgCl with 8.5O X is also bitter,the same holds for MgSO. 2... 

Relations between the bitterness of salts and their ionic diameter... 

In this equation b represents the average ionic diameter. HOckel has calculated b values for the following salts in aqueous solution ... 

At smaller ionic strengths (m < 0.05) the influence of the ionic diameter may be neglected for all practical purposes. Thus we may expect all dibasic indicator acids to have the same salt error in dilute electrolyte solutions provided that the buffers used in the pH measurement all have the same ionic strength and contain the same kind of ions. The buffer solutions in colorimetric pH determinations are, however, always considered as standards, and the pH of the buffer solution is taken as a standard value. Hence it follows immediately that the sign of the salt correction will be... 

The alkali and halide ions have played an important role in studies of ionic solutions. The reasons for this are obvious. The alkali halides form simple salts which are soluble in water. The ions have spherical symmetry and vary sufficiently in size, thus permitting studies of the dependence of solvation on ionic diameter. 

The exact calculation equations are given in [25], where it has also been proved that the Gibbs-Duhem equation is fulfilled. As well, NRTL parameters have been fitted up to molalities of 30mol/kg for a number of systems. Together with the ionic diameters, they are listed in [25]. Osmotic and mean ionic activity coefficients could be reproduced in an excellent way for a number of systems. Furthermore, the parameters fitted to binary systems have been successfully applied to ternary systems, that is, one salt in a binary solvent mixture, which always causes problems with the Electrolyte NRTL model [25]. 

Ionic diameters range from 1.56 to 3.30 A for the series Li through Cs but complexation with macrocyclic ligands results in an increase in cation diameter of 6-7 A in comparison to the cesium salt. Therefore, ions of the type [M(macrocyclic ligand)]+ have smaller surface charge densities than the M" " ions themselves. TTie ion-ion and ion-dipole interactions of these cations with an X" anion or solvent molecule are, accordingly, less effective than those associated with the alkali metal ions alone. 

Physical and ionic adsorption may be either monolayer or multilayer (12). Capillary stmctures in which the diameters of the capillaries are small, ie, one to two molecular diameters, exhibit a marked hysteresis effect on desorption. Sorbed surfactant solutes do not necessarily cover ah. of a sohd iaterface and their presence does not preclude adsorption of solvent molecules. The strength of surfactant sorption generally foUows the order cationic > anionic > nonionic. Surfaces to which this rule apphes include metals, glass, plastics, textiles (13), paper, and many minerals. The pH is an important modifying factor in the adsorption of all ionic surfactants but especially for amphoteric surfactants which are least soluble at their isoelectric point. The speed and degree of adsorption are increased by the presence of dissolved inorganic salts in surfactant solutions (14). 

The polycationic ammonium salt PEU can be chosen for increasing the ionic cloud in the electrical double layer, thus raising the electric repulsion between the gold particles in the sol. Small particles can be obtained (mean diameters between 3.1 and 4.2 nm) [24]. 

Recently, Dupont and coworkers described the use of room-temperature imi-dazolium ionic liquids for the formation and stabilization of transition-metal nanoparticles. The potential interest in the use of ionic liquids is to promote a bi-phasic organic-organic catalytic system for a recycling process. The mixture forms a two-phase system consisting of a lower phase which contains the nanocatalyst in the ionic liquid, and an upper phase which contains the organic products. Rhodium and iridium [105], platinum [73] or ruthenium [74] nanoparticles were prepared from various salts or organometallic precursors in dry 1-bu-tyl-3-methylimidazolium hexafluorophosphate (BMI PF6) ionic liquid under hydrogen pressure (4 bar) at 75 °C. Nanoparticles with a mean diameter of 2-3 nm... 

Upon increase in salt concentration to 2 M, histone octamers were obtained (Thomas and Butler, 1978). The octamer could be assembled from acid-extracted as well as from salt-extracted histones (Thomas and Butler, 1978). In a concentrated solution of the four core histones (prepared by acid extraction) at an ionic strength higher than 2 M NaCl (minimum 10 mg/ml histone concentration), there is a small fraction of assembled fibrous structures which can be observed in the electron microscope (Sperling and Bustin, 1976 Wachtel and Sperling, 1979). These fibers (see Fig. 3d) are 60 A in diameter and have a 330 A axial repeat, and were shown to be composed of the four core histones in an equimolar ratio (Wachtel and Sperling, 1979). The percentage of fibers in the solution of the four core histones is promoted by increase in histone and salt concentrations. 

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