Skeletal formula of <a href="https://en.wikipedia.org/wiki/Butane" class="extiw" title="en:Butane">butane</a>.
<a href="//commons.wikimedia.org/wiki/User:Yikrazuul" title="User:Yikrazuul">Yikrazuul</a>
2008-12-15
<span class="int-own-work" lang="en">Own work</span>