Single/Double Bonds in Resonance

[Sean Sugai 4E]

Because single and double bonds are considered one unit in the VSEPR model, does it matter which of the Lewis structures contribute to the resonance structure? What's an example of this?

[Michael Nguyen 1E]

I don't believe resonance structures really impact the VSEPR model. The model only depends on the number of atoms bonded to the central atom and the number of lone pairs on the central atom. Whether or not there is resonance, single bonds, or double bonds, it does not affect a molecule's shape according to the VSEPR model.

[Cynthia Gong 1L]

Single, double ,and triple bonds are all considered one region of electron density in the VSEPR model. So regardless of resonance structures, the shape of the VSEPR model won't be affected.

[Brian Tangsombatvisit 1C]

All of the different Lewis structures contribute to the resonance model since it is a blend of these structures. Because of this, all of the bond lengths in this type of atom are the same, but are in between a single and double bond's length. However, resonance does not affect a molecule's bond angles or shape.

For example, the carbonate ion, CO3(2-) is trigonal planar with bond lengths of 120 degrees, even if one of its bonds is a double bond and it has resonance.

[305421980]

In lecture today he explained that resonance does not need to be explained by more that one VESPR model structure because each bond (single, double, triple) only counts as one. The example he used was carbonate and showed how you only need one VESPR structure.

[Angela Patel 2J]

So all resonance structures for a molecule have the same shape? Is this always true?

[Megan Vu 1J]

Each bond for the single, double, and triple are essentially the same as looking at all single bonds. Thus, the resonance structures do not change what type of structure it is because each bond acts as a single region of electron density, which remains true for these resonance structures.