Diffusion cationic

The data given should serve only as reference values following the rule, the higher the ionic potential, the thicker the hydration layer of the water molecules around the ion, and the slower the ionic diffusion. Cations generally diffuse more rapidly than anions. 

Mn Mgi )2Si04 olivine mixture obtained by Morioka (1981). The concentration profiles are symmetric, indicating that the diffusivities are independent of the concentration of the diffusing ion. On the contrary, possible asymmetry in the diffusion profiles indicate that concentration depends significantly on the diffusing cations. In this case, the interdiffusion coefficient can be obtained by the Boltzmann-Matano equation ... 

These features make the design of suitable ligands that can displace water and bind both strongly and selectively to these freely diffusing cations a difficult task. The only basis for selectivity between alkali metal... 

As is seen, when the temperature rises, a considerable decoupling of the Li ions in liquid LiCl seems to take place. Decoupling of the cations is likely to help cationic self-diffusion more than cationic conductance, because in self-diffusion cations must interchange positions while in conductance they may move in parallel. In fact, corresponding to the temperature dependence of n in molten LiCl, an increase of D+/Ta (D+ = self-diffusion coefficient of the cations, A = equivalent conductance) with absolute temperature T has been observed for all molten alkali halides checked (30). (Also work is in progress at Mainz to check LiCl.)... 

In 2002, Morrow and Maginn presented an all-atom force field for [C4mim][PF6] using a combination of DFT calculations (B3LYP/6-311+G ) and CHARMM 22 parameter values [13]. MD simulations were carried out in the isothermal-isobaric ensemble at three different temperatures. The calculated properties contained infrared frequencies, molar volumes, volume expansivities, isothermal compressibilities, self-diffusivities, cation-anion exchange rates, rotational dynamics, and radial distribution functions. These thermodynamic properties were found to be in good agreement with available experimental values [13]. 

Gibbs-Donnan equilibrium exists in systems consisting of two fluid compartments separated by a semipermeable membrane, which permits diffusion of some ions (e.g., Na+, Cl ) but is impermeable to protein anions. Note that the concentration of diffusible cation in compartment 1 is greater than in compartment 2 and that osmotic differences exist between compartments 1 and 2. 

The fastest diffusing substance in alumina is hydrogen (H2). Fast-diffusing cations are sodium, copper, silver, with hydroniums (H30+) the fastest of these monovalent cations. Many other di- and trivalent cations have diffusion coefficients intermediate between these fast-diffusing ions and the slowest diffusers, the lattice elements aluminum and oxygen, which have about the same diffusion coefficients. 

If a second diffusible cation, H% is added to the system, then... 

Thus, if the total molar concentration of diffusible cation in the solution is mc, and the total molar concentration of anion is ma, and if one mol of the salt (component 3) contains v3c mols of cation and v3a mols of anion, then the molar concentration of component 3 is ... 

As pointed out already, since the inside of the cell is separated from the surrounding medium by a membrane with selective permeability, the potassium and chloride ions on both sides of the membrane are distributed according to Donnan distribution. The Donnan law states that the charges on both sides of the membrane are to be neutralized, and that the product of the diffusible ions on one side of the membrane equals the product of the diffusible ions on the other. In any cell, the diffusible cations (only potassium, since the membrane is virtually impermeable to sodium) traverse the membrane in order to neutralize the intracellular fixed negative charges (organic phosphates and carboxyl groups). 

Moyer et al. demonstrated that anion complexes of 57 could include large charge-diffuse cations, such as caesium and imidazolium, in the anion-induced calix [4]pyrrole cup [114]. Shielding of the imidazolium CH atoms in CD2CI2 in the presence of an anion-binding calixpyrrole was observed and considered as evidence for ion-pair complexation in solution. Similar behavior was also observed for N-ethylpyridinium cation [115]. 

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