electron number of an electrochemical reaction

symbol: $z$
synonyms: charge number, number of electrons transferred
https://doi.org/10.1351/goldbook.09063
Number of electrons transferred in a charge transfer reaction between an electrode and a single entity (ion, radical-ion, or molecule) of an electroactive substance, whose identity must be specified.
Notes:
  1. The apparent number of electrons transferred, \(z_{\rm{app}}\), represents the experimentally measured number of electrons transferred between an electrode and one electroactive substance species, whose identity must be specified. When the electrooxidation or electroreduction of a substance \(\ce{B}\) is accompanied by chemical processes, such as the catalyzed or induced reduction of a second substance, or a side reaction that consumes \(\ce{B}\) or an intermediate, the value of \(z_{\rm{app}}\) will differ from that of \(z\).
  2. Symbol \(n\) is commonly used when there is no risk of confusion with an amount of substance.
  3. Charge number is used in in the IUPAC Green Book.
Source:
PAC, 2020, 92, 641. (Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)) on page 648 [Terms] [Paper]