Mobility, definition ionic liquid

The definition of perfectly mobile and inert components should also be valid for cases of ionic diffusion in rocks and where no fluid is involved (Korzhinskii, 1965), but this possibility does not concern us here since clay mineral equilibria are dominated by the presence of liquid or fluid aqueous solutions. 

Ionic mobilities generally have a temperature coefficient of around -i-2.5%/degree, but it is not exactly the same for all ions. Incidentally, water viscosity has a temperature coefficient of approximately -2.5%/degree. This sometimes leads to the erroneous conclusion that ionic mobility is, by definition, inversely proportional to liquid viscosity, which is an oversimplification, originating also from the following relationship ... 

The authors state that while the above definition is used widely, other authors have defined tortuosity as 1/T, T, and l/T as these forms are frequently encountered in expressions for ionic conductivity and mobility through tortuous membranes. Experimental measurement of liquid membrane support tortuosity is described by Bateman et al. 

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