Question

What is the dipole moment for azulene?

Answer 1

The dipole moment of azulene is `color(blue)("1.08 D")` or `color(blue)(3.60×10^(-30) "C·m")`.

Explanation:

In the various resonance structures for azulene, the most stable contributors put negative charge in the 5-membered ring and positive charge in the 7-membered ring.

(from commons.wikimedia.org)

In effect, this gives an aromatic 6 π-electron five-membered ring fused to an aromatic 6 π-electron seven-membered ring, as we see in the above diagram.

This separation of positive and negative charge gives the molecule a dipole moment of `"1.08 D"`.