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Ionic liquids Stokes-Einstein relation

The Walden rule is interpreted in the same manner as the Stokes-Einstein relation. In each case it is supposed that the force impeding the motion of ions in the liquid is a viscous force due to the solvent through which the ions move. It is most appropriate for the case of large ions moving in a solvent of small molecules. However, we will see here that just as the Stokes-Einstein equation applies rather well to most pure nonviscous liquids [30], so does the Walden rule apply, rather well, to pure ionic liquids [15]. When the units for fluidity are chosen to be reciprocal poise and those for equivalent conductivity are Smol cm, this plot has the particularly simple form shown in Figure 2.6. [Pg.14]

Validity of the Stokes-Einstein Relation in Ionic Liquids... [Pg.654]

This equation was deduced in Section 4.4.8. It is of interest to inquire here about its degree of appiicabiiity to ionic liquids, i.e., fused salts. To make a test, the experimental values of the self-diffusion coefficient D and the viscosity tj are used in conjunction with the known crystal radii of the ions. The product D r//T has been tabulated in Table 5.22, and the plot of D tj/T versus 1/r is presented in Fig. 5.31, where the line of slope k/6n corresponds to exact agreement with the Stokes-Einstein relation. ... [Pg.655]

In polar liquids, ionic mobilities have been extensively studied, for instance by conductometry. They are known for many solvents (Robinson and Stokes, 1959 Janz and Tomkins, 1972). In low polar liquids, K has been deduced most often from transit time measurements, after irradiation of a thin layer of liquid or photoexcitation of the cathode, or after applying a voltage step. K values are now available in different liquids (Tables 1 and 2) but the nature of the corresponding ion is often unknown. So, to estimate the value of the mobility of a given ion in a liquid, the relation, Kt) = e/6nr, between K and the liquid viscosity Vi (Stokes-Einstein relation) is often used, where r is the hydrodynamic radius of the ion. In fact, this relation is only a crude approximation even for rather large ions, since the viscous forces are not the only retarding force acting on the ion, and the solvent is... [Pg.504]

E. Herald, M. Strauch, D. Michalik, A. Appelhagen, R. Ludwig, Dynamics of methanol in ionic liquids validity of the Stokes-Einstein and Stokes-Einstein-Debye relations, ChemPhysChem 15 (14) (2014) 3040-3048. [Pg.242]

Harris KR (2010) Relations between the fractional stokes- einstein and nemst- einstein equations and velocity correlation coefficients in ionic liquids and molten salts. J Phys ChemB 114 9572-9577... [Pg.97]


See other pages where Ionic liquids Stokes-Einstein relation is mentioned: [Pg.153]    [Pg.355]    [Pg.153]    [Pg.69]    [Pg.195]   


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