What are the oxidation numbers of each oxygen atom in ozone?

1 Answer
Oct 9, 2015

What is the oxidation state of the individual OO atoms in ozone: from left to right, -I, +I, OI,+I,O. (O^(-)-O^(+)=OOO+=O).

Explanation:

Oxidation state/number is of course a formalism. It is the charge left on the atom when all the bonding pairs are broken, and the charge goes to the most electronegative atom. Here, we have oxygen-oxygen bonds. The bond is cleaved homolytically, with the 2 (or 4) bonding electrons shared between the oxygen atoms.

From left to right, there are (7+2)e^-(7+2)e, 7e7e, and 8e8e. The atomic number of oxygen is 88, i.e. 8 protons; of course this means from left to right the formal charge on each atom is -1, +1,1,+1, and 00). Of course this a formalism, but it nevertheless means that the formal charge of the bent ozone molecule is ZERO (-1 + 1 + 0)(1+1+0), even if the individual oxygen atoms have different formal oxidation states, and we can draw the other resonance structure such that the order of charge is reversed.