**7. Fenton chemistry for beginners**


structure of the oxidant as (Fe = O)+3 (perferryl-oxo ion) in 1990, and the bifurcated oxygen addition mechanism in 1992.


Addition of Fe+2 (or Fe+3) ions first allows the metal ions to associate with and/or chelate onto the substrate. Addition of H2O2 now creates the ferryl-oxo (or perferryl-oxo) ions adjacent to the substrate, increasing the likelihood of in situ oxidation at the ion's binding site, creating uneven product profiles, as observed in Ovalle et al. (2020). Allowing binding of metal ions to substrates before addition of H2O2 can explain observations of noncanonical "crypto-hydroxyl-" substrate oxidations previously observed by many authors.

8.This summary is not an exhaustive history, nor is it the full collection of all the articles I read. However, it took me many years to both acquire and understand the chemistry of each oxidant. I did not address other metal/peroxide systems (such as copper-Fenton chemistry) here as it was not relevant to either Ovalle et al. (2001) nor (2020).

This article is written as a guide for newcomers so that they have a head start in finding the papers they need for their research. Welcome to the club!
