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I would like to know whether the electronegativity of atoms will affect the molecular geometry of a molecule.

For example, the molecule $\ce{CHFCl2}$. Originally I thought that as fluorine was the most electronegative, it would have a stronger partial negative charge, so the shape of the molecule would not be tetrahedral. I also thought that as carbon has a higher electronegativity, there would be a partial positive charge at the carbon atom. Can anyone explain whether the electronegativity of atoms in a molecule can affect the shape of the molecule? In $\ce{CHFCl2}$ why can $\ce{CHFCl2}$ even have a tetrahedral shape although I think the charges cannot cancel out?

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    $\begingroup$ It can, but so can the atom radius. $\endgroup$
    – Poutnik
    Jul 16, 2022 at 11:22
  • $\begingroup$ Could you give some examples? Are there certain conditions for that to happen? $\endgroup$ Jul 16, 2022 at 11:23
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    $\begingroup$ I will wait a day, and if you will not have been able to find any and will have justified it, I will provide some. // Before all that, check if your assumptions are correct $\endgroup$
    – Poutnik
    Jul 16, 2022 at 11:31
  • $\begingroup$ Hint: look up "VSEPR" $\endgroup$
    – Andrew
    Jul 16, 2022 at 17:36

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Under special circumstances, yes. For example, the NIST Web Book entry for tris(trifluoromethyl)amine (not the preferred IUPAC name, written here in an acceptable name for the sake of intuitivity) clearly gives a trigonal planar coordination geometry at nitrogen, while e.g. the valence isoelectronic trimethylamine has the VSEPR-expected (3BD1LP) triangular pyramidal geometry at nitrogen- this is due to negative hyperconjugation from the nitrogen lone pair to the C-F antibonding orbital, which is promoted by the so high electronegativity of fluorine. This effect is quite general, and is called the anomeric effect(Warning: PDF auto-download)

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    $\begingroup$ I suspect OP meant slight deviations from perfect tetrahedron not entirely different classes of structures $\endgroup$
    – Andrew
    Jul 16, 2022 at 17:37

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