What is the difference between bond stretching and bond bending? and Lewisporte and Sir Robert Bond

What is the difference between bond stretching and bond bending?

When reading IR specs, what exactly is bond bending? I understand stretching somewhat, energy is absorbed and the bond stretches from the increase in energy, and higher absorbency means higher wave number and stronger bond, but I dont really understand what bond bending is... is that like rotational energy is introduced?

Also a side question, what is the difference between symmetrical and asymmetrical compound readings?

Thanks ahead of time for any help.


Bond best answer:

Answer by mnrlboy
Sal,

Bond bending is when the angle between two different bonds changes..... for example, if the two hydrogen atoms in a water molecule move closer together, it may not change the O-H bond distances, but it will change the angle between the O-H bonds to something less than the normal 104 degrees. (Imagine sticking your arms out away from you, and then clapping them together).

In the context of spectroscopy, "symmetrical" and "asymmetrical" probably refers to the symmetry of a stretching or bending motion, and whether it has a center of symmetry. For instance, a motion that has a center of symmetry will not create an electric dipole, and therefore won't be IR active (meaning that it won't absorb any IR radiation).

Bond

Lewisporte and Sir Robert Bond


Image by Product of Newfoundland
Lewisporte Marina and the Sir Robert Bond Ferry preparing to leave for Labrador.

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