thickness of electrical double layer

https://doi.org/10.1351/goldbook.T06343
The length characterizing the decrease with distance of the potential in the double layer = characteristic @[email protected] length in the corresponding electrolyte solution = \(\kappa^{-1}\):
\[\frac{1}{\kappa } = \sqrt{\frac{\varepsilon_{\text{r}}\varepsilon_{0}RT}{F^{2}\sum _{i}c_{i}z_{i}^{2} }}\]
(rationalized four-quantity system)
\[\frac{1}{\kappa } = \sqrt{\frac{\varepsilon_{\text{r}}RT}{4\pi F^{2}\sum _{i}c_{i}z_{i}^{2} }}\]
(three-quantity electrostatic system)
where \(\varepsilon\) = static @[email protected] = \(\varepsilon_{\text{r}}\varepsilon_{0}\), \(\varepsilon_{\text{r}}\) = relative static @[email protected] of solution; \(\varepsilon_{0}\) = @[email protected], \(R\) = @[email protected], \(T\) = @[email protected], \(F\) = @[email protected], \(z_{\text{i}}\) = concentration of species \(i\), \(z_{\text{i}}\) = ionic charge on species \(i\).
Source:
PAC, 1972, 31, 577. (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 619 [Terms] [Paper]