Bond Length and Resonance

[Ryan Troutman 4L]

I'm confused on the aspect of how the number of bonds influences the length. In the case of a single and a triple bond, is the single bond longer than the triple bond(and why)? When we use resonance do we assume that the bond lengths are the same? Thanks :)

[yast_27]

Hi

you should checkout this website (it explains everything really clearly, i usually go there when i'm looking for further info)
I'm going to quote the important part of this article for your question:
https://chem.libretexts.org/Textbook_Ma ... _Chemistry)/Chemical_Bonding/Fundamentals_of_Chemical_Bonding/Bond_Order_and_Lengths
"The higher the bond order, the stronger the pull between the two atoms and the shorter the bond length. Therefore, bond length increases in the following order: triple bond < double bond < single bond."
for resonance, you have to do the average bond lenght of one of the model and this would be the bond lenght of every bond.

[Sophia Ding 1B]

Just building off, the number of bonds do affect bond length in that the greater amount of bonds, the shorter the bond length (so triple bond is the shortest). This is because a triple bond is much stronger than a single bond, and thus would have much more pull between the two atoms to thus have a shorter length. For resonance, I want to say for the most part I would assume all the bond lengths are the same, in that all the bond lengths are a mixture of the possible resonance structure (e.g. like an intermediary between the length of a single and double bond for all present bond lengths in the Lewis structure).

[Sameen Mahmood 3D]

Generally, the longer a bond, the weaker a bond. Because triple bonds consist of very high electron density between two atoms, the charges are centralized between the two nuclei which brings them closer together, creating a stronger, shorter bond. And with resonance yes the bonds are the same as long as they're between the same two atoms.

[Mallory_Podosin_1H]

Single bonds are longer than triple bonds because they are weaker. I am pretty sure this is because there is less pull on the electrons by the nuclei of the atoms that are bonded, so the bond is easier to break when it is longer. In resonance structures, all the bonds between elements with resonance are the same length because they are an average of the different resonance structures.

[yuetao4k]

Bond lengths are the same. Resonance structures give different locations for the different types of bonds, but lengths of the bonds are the same.