Difference between bond angle strain and steric strain

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shannon_tseng_3L
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Joined: Wed Sep 21, 2016 2:56 pm

Difference between bond angle strain and steric strain

Postby shannon_tseng_3L » Mon Mar 13, 2017 3:11 pm

What's the difference between bond angle strain and steric strain?

Chem_Mod
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Re: Difference between bond angle strain and steric strain

Postby Chem_Mod » Mon Mar 13, 2017 3:55 pm

Great question. The two can be related, but not always. The simple answer is that steric strain is strain that cannot be alleviated by just changing the bond angle.

For example, cyclopropane and cyclobutane both exhibit high angular strain, but not really any steric strain. The best example of steric strain is that which we studied in class, namely the various conformations of butane. When the two end carbons are "eclipsed" over each other, the steric strain is much higher than if the end carbons (think of them as methyl groups) are staggered or "gauche." The image below demonstrates this.

Image

Image credit: http://research.cm.utexas.edu

AnnaTong1E
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Joined: Fri Jul 15, 2016 3:00 am

Re: Difference between bond angle strain and steric strain

Postby AnnaTong1E » Mon Mar 13, 2017 6:10 pm

Is there a clear definition for steric strain?


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