Most understandable notation for reduction and oxidation potentials

Nowadays a lot of electrochemistry is done using just electrode potentials (i.e. reduction potentials), so if in doubt the notation $E^o$ tends to imply a reduction potential. However, some chemists use the perfectly acceptable convention that oxidation reactions are accompanied with oxidation potentials. 


I wondered whether anyone could inform me about the most unambiguous or widely used conventions for indicating which type of potential is being employed when written next to a half equation.


For instance, for the **oxidation** half equation $Ag \rightarrow Ag^+ + e^-$, I could write the associated potential in a number of ways:


1. $E\_{Ag^+/Ag} = +0.80V$ - the electrode potential of the $Ag^+/Ag$ couple
2. $E\_{red}(Ag^+/Ag) = +0.80V$ - the reduction potential of the $Ag^+/Ag$ couple
3. $E\_{ox}(Ag^+/Ag) = -0.80V$ - the oxidation potential of the $Ag^+/Ag$ couple
4. Often, just $E$, or some other notation!


I think the notation in points 1 through 3 is fairly clear, with the first two applicable to the European convention and the third applicable to the American convention, when written next to the oxidation equation. However I was wondering if anyone more experienced could advise as to what the most common conventions in the field are! 


Thank you!




I don't know why your textbook author is confusing and still teaching American & European conventions. It is obsolete now. I will show you how oxidation potentials were quoted by American electrochemists in the 1950s-60s. Have a look at the table [Latimer's book: Oxidation States of the Elements and their Potentials in Aqueous Solutions pg 340](https://archive.org/details/oxidationstateso00lati/page/340/mode/1up). This was a very famous book of its time. Latimer and Gibbs had great influence on American science and thermodynamics.


I would say you should stick to only (1). Your number 3 is not correct because you are still writing the cell as reduction. The correct version would be


$E\_{ox}(Ag/Ag^+) = -0.80V$ - the oxidation potential of the $Ag/Ag^+$ couple, so that you are consistent. 


Also make sure your instructor is aware of these things (American European conventions, and that the sign of the electrode potential is an electrostatic one, and that electrode potential does not care how the equation is written. You seem to know more than an average PhD student). I will not be surprised, your instructor is not a trained electrochemist, he/she may not be aware of these subtleties.


Also note that the small "o" on E, indicates standard conditions.


[![Oxidation potentials](https://i.stack.imgur.com/PVtAe.png)](https://i.stack.imgur.com/PVtAe.png)


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