Ok so I'm confused about the mechanism for this process:
Now the idea here is that iron first becomes oxidised to Fe(III) by placing an electron in the antibonding orbital of dioxygen. This is followed by the addition of 2 electrons from an external source. This causes the splitting of the O-O bond resulting in the formation of a hydroxide ion. In addition, iron loses another electron to oxygen forming the Iron(IV) oxide species shown.
Now what I do Not understand is the overall charges on the species at the end. I feel as if the original O-Fe(III) bond was considered purely ionic hence the lack of a formal charge on oxygen, yet at the end it seems as if the O=Fe(IV) bond is covalent, otherwise there would be a negative 2 charge on oxygen!
Is there a switch between ionic and covalent formalisms in the middle of this process?
If anyone could help explain the charges with perhaps a curly arrow mechanism to indicate the numbers of electrons on each atom then that would be most appreciated!