Dipole moments and Shape

[OzzyMMSection2J]

How does a dipole moment affect shape? And is there a way to remember which shapes would be considered to have dipole moments?

[Jane Ling Dis3E]

I don't think dipole moments affect shape - rather, it's the shape that'll affect the direction of dipoles. Take H2O for example, without applying the repulsion between lone pairs and bonds, you'd assume that the shape is linear and the dipole moments cancel eachother out. However, given that the lone pairs will repel the bonds away from each other, H2O has an overall dipole moment because of the bent shape. In terms of which shapes will have dipole moments, I think typically trigonal pyramidal, seesaw, T-shaped, and square pyramidal dipoles won't be able to cancel each other out, so they'll likely always have a non-zero dipole moment (however I'm not too too sure).

[506047744]

Dipole moments do not affect shape