Terminology

The terminology used in our project differs in part from the one conventionally used in redox chemistry. Thus, it needs to be evaluated if a new terminology is needed or if it is unnecessary and confusing.

From a didactical standpoint, the historically evolved terminology within redox chemistry is far from being intuitive compared with the terminology used in acid base chemistry. Here, the focus on the proton as being the reason for an “acid” or “acidity” resulting in the expressions “protonation” and “deprotonation” is self-explanatory.

On the contrary, the quality “reducing” or “reductive” often is seen as being inherent to the molecule, which is able to “reduce” another one; from this phrase it remains unclear that an electron is transferred in this process. Furthermore, in redox chemistry the counterpart to this expression is “oxidizing”. Likewise, it is not evident that an electron is the actual principal player in an oxidation process. The fact that a reducing agent is oxidized concomitantly with an oxidizing agent being reduced whereby the direction of electron transfer is not intuitive during a redox reaction, creates confusion for beginners in chemistry, for non-chemists and even for professionals.

We therefore adopted the terminology of Bockris and Reddy^[1] they used in their textbook of electrochemistry in the 1970s and also found entry into the IUPAC gold book^[2] “electronation” and “deelectronation” being as self-explaining as “protonation” and “deprotonation”. To complete the analogy to acid/base chemistry, which is also covered in this article, we use the expression “reducity” to indicate the reducing power of a medium.

This was done for three reasons: 1) conciseness, 2) accentuation of the analogy to acid–base chemistry, and 3) distinction from the general term “reduction”, which also translates to “decrease” or “diminishment of something” and therefore is misleading—except for those who remember the historic background of the reaction of metals with oxygen, the oxidation, and the return, the reduction, of metal oxides to metals.

Here is a brief summary of the expressions we use.

We are quite aware that introducing new expressions may lead to even more confusion than to more clarity. However, we are convinced that in redox chemistry more clarity concerning nomenclature is required. This can be achieved, if the parallelism to the acid–base chemistry is utilized by focusing on the particle of interest: the view on the proton with its acidity has to be given a counterpart. This is the focus on the electron with its “reducity”. Likewise, the “oxidity” is opposed to the basicity, but these terms should be avoided, since both are in fact redundant and lead to confusion.

[1] J. O. M. Bockris and A. K. N. Reddy, Modern Electrochemistry, Plenum Press, New York, 1970.

[2] M. Nič, J. Jirát, B. Košata, A. Jenkins, A. McNaught (Eds.) IUPAC Compendium of Chemical Terminology, IUPAC, Research Triagle Park, NC, 2009.