<p><a href="https://en.wikipedia.org/wiki/Skeletal_formula" class="extiw" title="w:Skeletal formula">Skeletal formulae</a> of the basic structures of <a href="https://en.wikipedia.org/wiki/penicillin" class="extiw" title="w:penicillin">penicillin</a> (1) and <a href="https://en.wikipedia.org/wiki/cephalosporin" class="extiw" title="w:cephalosporin">cephalosporin</a> (2) antibiotics, highlighting the <a href="https://en.wikipedia.org/wiki/beta-lactam" class="extiw" title="w:beta-lactam">beta-lactam</a> ring (red). Created using <a rel="nofollow" class="external text" href="http://www.acdlabs.com/download/chemsk.html">ACD/ChemSketch 10.0</a> and <a href="https://en.wikipedia.org/wiki/Inkscape" class="extiw" title="w:Inkscape">Inkscape</a>.
</p>
<dl><dt>Legend</dt></dl><div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:thin solid #333;background:red;color:#202122;text-align:center;"> </div> <a href="https://en.wikipedia.org/wiki/Beta-lactam" class="extiw" title="w:Beta-lactam">Beta-lactam</a> ring</div>
<a href="//commons.wikimedia.org/wiki/User:Fvasconcellos" title="User:Fvasconcellos">Fvasconcellos</a> 19:02, 23 October 2007 (UTC)
<span class="int-own-work" lang="en">Own work</span>