Physics, asked by Samiksha9836, 1 year ago

Why sigma bonds are stronger than pi bond

Answers

Answered by smriti24
15
pi bonds are usually weaker than sigma bond . quantum mechanics says this is becoz the orbital path are parallel. so , there is much less over between the p orbitals.
Answered by anshul001
14
The reason behind this is the orientation of the overlapped orbitals. Sigma bonds result from head-on(co-axial) overlapping while pi bonds are outcome of lateral(para-axial) overlapping. Here is a pictorial representation of ethene(sp2 hybridized C atoms) :

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The greater the extent of overlapping, the higher the probability of finding the valence electrons in between the nuclei and hence the bond will be stronger & shorter.

In MOT, this can be explained using Overlap Integral. This is how Atkins depicts it :

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In simple terms, after forming a sigma-bond (a pre-requisite for pi-bonds), the two atoms get locked along the inter-nuclear axis. As a result, the orbitals available for pi-bonding can only partially overlap, thus forming a weaker bond.
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