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    Hi
    I have to draw Valence Bond hybrid orbital model but when i hybridize the porbitals i don't know which one i am suppose to leave out.For example in an sp2 orbital so i leave out 2p x y or z?

    Hope you understand what i mean

    Thanks
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    (Original post by sarah170194)
    Hi
    I have to draw Valence Bond hybrid orbital model but when i hybridize the porbitals i don't know which one i am suppose to leave out.For example in an sp2 orbital so i leave out 2p x y or z?

    Hope you understand what i mean

    Thanks
    Well, I suggest you read this page :

    http://www.chemguide.co.uk/basicorg/.../benzene2.html
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    Thanks but what i mean it after promotion and say you are doing an sp2 hybridisation how do you know which p orbital to leave out e.g x y or z?
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    (Original post by sarah170194)
    Thanks but what i mean it after promotion and say you are doing an sp2 hybridisation how do you know which p orbital to leave out e.g x y or z?
    The orbitals are assigned x,y,z on the basis of a three dimensional axis that is randomly assigned. If you turn the atom over the assignments change.

    What I'm trying to say here is that all three orbitals are equivalent and degenerate so it really does not matter which one you "leave out".

    Normally it's the pz orbital that remains after sp2 hybridisation (even though it is then drawn vertically suggesting that it is a py orbital)
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    oh okay thanks for clearing that up.
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    (Original post by charco)
    The orbitals are assigned x,y,z on the basis of a three dimensional axis that is randomly assigned. If you turn the atom over the assignments change.

    What I'm trying to say here is that all three orbitals are equivalent and degenerate so it really does not matter which one you "leave out".

    Normally it's the pz orbital that remains after sp2 hybridisation (even though it is then drawn vertically suggesting that it is a py orbital)

    (Original post by sarah170194)
    oh okay thanks for clearing that up.
    It is worth noting that in the hybridisation model all orbitals are considered to be equivalent, but if you use a symmetery analysis (which you may or may not have covered yet), then the pz, py and px can be different.
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    oh yes it mentioned about symmetry analysis and that's why i got confused. What is it?
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    (Original post by sarah170194)
    oh yes it mentioned about symmetry analysis and that's why i got confused. What is it?
    Basically within the point group of the molecule, the px, y and z orbitals will have their own symmetery. For some molecules they will be the same (for example in tetrahedral methane).

    However, in a molecule such as carbon monoxide (C(infinity)v ), the px and py have the same symmetery, but the pz is different. This is relevant because only orbitals of the same symmetery can mix so it defines which orbitals are part of which bond and which holds the lone pair.

    If this isn't making a lot of sense then you haven't covered it yet and don't worry about it.
 
 
 
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