# 14.18
Both naphthalene and azulene have 10 pie electrons and are aromatic.
Pentalene is apparently antiaromatic and is unstable even at -100
degrees C. Heptalene has been made but it adds bromine, it reacts with
acids, and it is not planar. Is Huckle’s rule applicable to these
compounds? If so, explain their lack of aromaticity.
