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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: o0CY0o on December 21, 2008, 03:48:58 AM

Title: About MO theory
Post by: o0CY0o on December 21, 2008, 03:48:58 AM
I got 2 questions about it.
Can anyone help me out with the MO theory energy diagram of CN-?
It is heteronuclear diatomic molecule, however, both have Z smaller than 8. Would the sp interaction affect it?
Another question is about s-p interaction. Even though i understand it happens, I do not know the principle behind. Can anyone tell me?
Thanks
Title: Re: About MO theory
Post by: opuktun on December 24, 2008, 09:56:07 AM
Erm, I'm not a physical chemist and it's been a while since I was taught on MO.

You can refer to http://www.mpcfaculty.net/mark_bishop/molecular_orbital_theory.htm
and examine the part for carbon monoxide. The MO structure is the same for cyanide.

As for "It is heteronuclear diatomic molecule, however, both have Z smaller than 8. Would the sp interaction affect it?", if I interpret your question correctly, sp interaction will not affect the MO.

When speaking about s-p interaction, I am inclined to recall the idea of sp hybridization in organic chemistry. (see http://en.wikipedia.org/wiki/Orbital_hybridisation ) This interaction, in my own thinking, comes about because of the mixing of electron clouds and the strength of the positive nuclei. As we know that s orbitals are spherical and p orbitals are dumbbell, spx hybridized (x=1,2 or 3) is a result of the "mixing" of these s and p orbitals which form sigma bonds. Pi bonds are formed by the left over p orbitals not hybridized.