How do you calculate the formal charge of O3?

1 Answer
Nov 7, 2015

The formal charge of the ozone molecule is zero. Its Lewis structures do present charge separation.

Explanation:

With simple VSEPR considerations, there are 18 valence electrons to distribute around the 3 oxygen atoms (24 electrons in total; 6 are inner core).

Typically, a Lewis structure of O=..O+O, would be depicted. Going from left O to right O and including the 2 inner core electrons on each atom, there are 8, 7, and 9 electrons around each oxygen centre, resulting in formal charges of 0, +1, and 1, respectively. Of course, I can draw the other resonance structure, but the Lewis structure has the same electronic formulation. The OOO 117; this is slightly LESS than the normal sp2 bond angle of 120, due to disproportionate influence of the oxygen lone pair, which tends to compress OOO.

Since the central oxygen has 3 regions of electron density, this molecule is bent.