What does this mean:

[chiddler]

(context: the best explanation for the stability of the chair conformation of cyclohexane is)

The bonds have non linear overlap.

This answer is not true, but I don't understand what it means.

---

Members don't see this ad.

 

[CodeRedDew]

I believe it is referring to the fact that there is zero ring strain in cyclohexane. It doesn't experience ring strain because of the bond angles being as close to 109.5 as possible and that it doesn't experience any torsional strain as well. Torsional strain is the overlap of electrons between bonded atoms so I'm guessing this is what they are referring to when they state "non-linear" overlap.

 

[chiddler]

thanks for your help, but i don't understand what you mean.

i probably misunderstood what you wrote, but just in case: remember that what I wrote is NOT true.

 

[MedPR]

(context: the best explanation for the stability of the chair conformation of cyclohexane is)

The bonds have non linear overlap.

This answer is not true, but I don't understand what it means.

I believe it is referring to the fact that there is zero ring strain in cyclohexane. It doesn't experience ring strain because of the bond angles being as close to 109.5 as possible and that it doesn't experience any torsional strain as well. Torsional strain is the overlap of electrons between bonded atoms so I'm guessing this is what they are referring to when they state "non-linear" overlap.

thanks for your help, but i don't understand what you mean.

i probably misunderstood what you wrote, but just in case: remember that what I wrote is NOT true.

Lesser carbon rings... eh that doesn't make sense.

Rings like cyclopropane exhibit nonlinear orbital overlap shown here:

As opposed to cyclohexane (benzene here):

 

[MedChad]

Medpr's picture shows it best, but just to reiterate their are different kinds of overlap that can be observed. One may completely overlap while other types like the sideways overlap do not. The bonds are linear in the chair conformation since this position allows equatorial position of the substituent, which is the ideal position for the substituent. This question also has to deal with ring strain I thought but could be wrong with that.

 

[mcloaf]

I would caution everybody in this thread against spending too much time worrying about the meaning of an incorrect answer. Often the test writers write wrong answers with terms that are relevant to other areas (see MedPR's post) and in doing so are able to mislead test takers who get overwhelmed and simply guess at a term they have seen before and for which they can't remember the context.

As for the stability of chair, it is not because of ring strain. Ring strain makes cyclohexanes and cyclopentanes stable, but doesn't necessarily favor chair over twisted or boat. The reason everybody loves the chair is that it minimizes steric interactions among substituents on adjacent carbons of the ring. That is, if you were to look down the newman projections for all the carbon-carbon bonds in chair form cyclohexane, nothing will be eclipsed.

 

[MedPR]

Yes, as the above person said, you have to consider torsional strain and steric strain