Charged vs polar species

christian0710

Hi,
Is it correctly understood that all charged molecules are polar (if they have a charge at some point, they must also have a unequal distribution of positivity and negativity)

but polar molecules can be charged or uncharged ( they have Δelectronegativity)

DrClaude

You have to take into account symmetry. I'm pretty sure that H₂⁺ is non-polar!

christian0710

Ahh yes that makes sense! thank you :)
So in the case of H2(+) I could imagine there are (if one can say) two resonance form, where 50% of the time the electron is most at Hydrogen A and the other 50% most at hydrogen B.

DrClaude

In a simple classical picture, yes. Quantum mechanically, you just have to see the electron as being in an orbital that stretches symetrically over the two hydrogen nuclei.