Bond Length

[Yeprem]

Is there a cutoff value for considering a bond overwhelmingly single-bonded or ample double-bonded?

[JoshMoore2B]

Is there a cutoff value for considering a bond overwhelmingly single-bonded or ample double-bonded?

I believe that this is a pretty discretionary thing, so it is up to the individual. Generally, I would say something is overwhelmingly single- or double-bonded if the measured values for the bond lengths are very close (i.e. the bond length is usually 120 pm, and in the molecule it is observed to be 121), while ample is tending towards that length (i.e. 127-130). Overwhelmingly seems to be a very strong word, and so I would think it would need very strong evidence to support it.

[Samudrala_Vaishnavi 3A]

I've noticed that for bond length reference points it tends to vary based on the example you are looking at in terms of homework questions. There will usually be a table given to you of the experimental bond lengths compared to the actual bond lengths of the Lewis structure you are looking at. In this way, you can gauge the accuracy of the wavefunctions for hybrid Lewis structures thinking application-wise. There is not really a set cut off from what I know.

[Brian_Wu_3B]

Usually I just choose whichever one the actual bond length is closer to. Although I'm not sure if that's correct. What do you guys do?

[Anna Yakura 2F]

I just choose the bond type that the number is closest to, but in the case of an exam I would think the professor would give us a straightforward number.

[Charlotte Adams 1A]

When doing the Sapling, if the length of the bond was closer to that of double bonds, the answer was that it had more double bonds.