Why is the bond length of O3 longer than O2 ???

Question

Bond length of O2 is 0.121 nm.
Bond length of O3 is 0.128 nm.

Answer 1

Hand-wavy answer:

The O2 bond is a double-bond (12 valence shell electrons) or bond order of 2.0.

The O3 molecule (18 valence shell electrons) has 2 (reasonable) resonance forms with a double and single bond:

O-O=O <--> O=O-O

That "averages" to a bond order of 1.5. The general trend is that bond length decreases with bond order (single bonds are longer than double which are in turn longer than triple bonds).

The not-so-handwavy answer gets into MO Theory, if you want to read up on it. ;-)

Answer 2

O3 has a higher charge density compared to O2 thus greater repulsion is exhibited by the constituent atoms of O3 than those of O2, I think

Answer 3

I agree with Lovely, and also, the valence bond is longer in ozone because the two oxygens in O3 don't share electrons as much as the two oxygens in O2 molecule.

Answer 4

because it's O=O-O and there is resonance so there's also O-O=O. which results in a hybrid bonds. the lone pairs on the oxygen repell each other because they're high energy which lengthens the bonds.

Answer 5

The repulsion is greater, due to the greater charge density.

Each O atom is pusing against two others - and they are both pushing on it - so they come to a different position.

I think.

Answer 6

Because the elements need to be farther apart since there are three of them instead of two.