Space-filling model of the <a href="https://en.wikipedia.org/wiki/Diacetylene" class="extiw" title="w:Diacetylene">butadiynyl</a> radical.
<a href="//commons.wikimedia.org/wiki/User:Benjah-bmm27" title="User:Benjah-bmm27">Ben Mills</a> and <a href="//commons.wikimedia.org/wiki/User:Jynto" title="User:Jynto">Jynto</a>
Derived from <a href="//commons.wikimedia.org/wiki/File:Ethynyl-radical-3D-vdW.png" title="File:Ethynyl-radical-3D-vdW.png">File:Ethynyl-radical-3D-vdW.png</a>.