A Chemical Reaction Interposed Between Two Electron Transfers

3 A Chemical Reaction Interposed Between Two Electron Transfers. An electrochemical process in which the product of the electron transfer undergoes a chemical reaction that generates a species which in turn is electrochemically active is defined as an ECE mechanism. It is commonly schematized as  

Such a series of events can have associated aspects of more or less complicated nature depending upon 12 

1 An irreversible chemical reaction interposed between two reversible one-electron transfers (case R-R). The so-called ErQEr process, if n — n2 = 1, can be written as  

Amongst the ECE mechanisms, this one is perhaps the most commonly encountered in inorganic electrochemistry. 

The cyclic voltammetric response depends on the separation between E2 and E, or AE0. Hence, several cases are possible depending on whether  

---

This being stated, the occurrence of a chemical reaction interposed between two electron transfers can be easily detected by plotting a graph of i vs. 1/2 20,22 pjgure 53 shows that at short times after the potential step (corresponding to kf = 0) the current depends only on the process Ox — Red, thus the slope of the function depends on the number , of electrons. 

---