Plots in the Case of Two Adsorbed Species

The second term in Eq. (166) represents a second-order electrochemical impedance, 5 and its denominator may be expressed in the following form  

Depending on the value of the parameter the poles of the second term of Eq. (167) are real or imaginary. Taking into account Eq. (167), there are 54 theoretically different cases of poles and zeros. They were considered systematically in Ref. 95. The faradaic impedance may be represented by many different equivalent circuits, depending on the sign of parameters B and C and relative values of all the parameters. Its complex plane plots display different forms from two capacitive semicircles through various capacitive and inductive loops to two inductive loops. In order to obtain the total impedance, the double-layer capacitance and solution resistance should be added to the faradaic impedance. Some examples of complex plane plots of faradaic impedances are presented in Eig. 26. 

Faradaic Impedance for a Process Involving Three or More Adsorbed Species 

Similarly to the case of two adsorbed species presented above, more complicated cases may be considered. Such a case is often found in corrosion. Assinning the existence of three adsorbed species, a system of equations similar to Eqs. (157)-(159) may be written  

Some examples of the complex plane plots obtained for the case of two adsorbed 

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