The Mn nitrenoid fragment in 20 is potentially redox non-innocent; thus the formal oxidation states of the Mn nitrenoids in the forgoing discussion are based on counting the nitrenoid fragment as a 2-ligand (i.e., imido nomenclature). In the context of a formally Mn(IV) imido complex, N-centered non-innocence could result in a species more appropriately described as either a Mn(III) adduct of an iminyl radical anion (RN •-, S = 1/2) or as a Mn(II) adduct of a singlet nitrene ligand (S = 0). Applying the Enemark-Feltham nomenclature, the Mn(IV) imide would be described as {MnNR} .