[JohnTan]

Hi guys, I was just wondering, does having a charge on an atom in a molecule automatically make this bond a dipole if the other atom has no charge? or is it still based on electronegativity?

[Jorriss]

Not necessarily, if it's singular like you said it would but not always.

Look at the sulfate ion. It has a net charge but if you evaluate the resonance structures there's no net dipole in any direction so it's non polar.

It's all about electronegativity and symmetry.

[Schrödinger]

does having a charge on an atom in a molecule automatically make this bond a dipole if the other atom has no charge?

What do you mean the other atom has no charge? There is never an ion without a counter-ion. So, every ionic molecule is a dipole.

[Jorriss]

does having a charge on an atom in a molecule automatically make this bond a dipole if the other atom has no charge?

What do you mean the other atom has no charge? There is never an ion without a counter-ion. So, every ionic molecule is a dipole.

I assumed he was referring to formal charges, where the adjacent atom in the molecule has no formal charge. Like an acetylide

[oxyflo]

If the difference in electronegativity is greater than 1.5 the bond is ionic. between 0.3 to 1.4 would be in the range of polar covalent.