Cyclohepta-1,3,5-triene with negative charge. Diagram of molecular orbitals included.
<a href="//commons.wikimedia.org/wiki/User:Ji%C5%99%C3%AD_Janou%C5%A1ek" title="User:Jiří Janoušek">Jiří Janoušek</a>
<span class="int-own-work" lang="en">Own work</span>