Molecular structure of <b><a href="https://en.wikipedia.org/wiki/ammonia" class="extiw" title="w:ammonia">ammonia</a></b> showing lone electron pair
<a href="//commons.wikimedia.org/wiki/User:Booyabazooka" class="mw-redirect" title="User:Booyabazooka">Booyabazooka</a> (vectorization)
2006-05-31
<span class="int-own-work" lang="en">Own work</span>