## thickness of diffusion layer

in electrochemistry
https://doi.org/10.1351/goldbook.T06342
The distance from the electrode where the ratio $\frac{c\,-\,c_{\text{e}}}{c_{0}\,-\,c_{\text{e}}}$ reaches a given value. ($$c_{\text{e}}$$ is the @[email protected], $$c$$ is the concentration, $$c_{0}$$ is the value in the bulk solution.) If this ratio is selected as, say, 0.99 the corresponding thickness of the @[email protected] layer is denoted by $$\delta_{0.99}$$.
See also:
diffusion layer
Source:
PAC, 1981, 53, 1827. (Nomenclature for transport phenomena in electrolytic systems) on page 1837 [Terms] [Paper]