SVG version of <a href="//commons.wikimedia.org/wiki/File:Nitric_acid_resonance_median.png" title="File:Nitric acid resonance median.png">Image:Nitric_acid_resonance_median.png</a>, which is PD.
<a href="//commons.wikimedia.org/wiki/User:ScottSteiner" title="User:ScottSteiner">ScottSteiner</a>
<span class="int-own-work" lang="en">Own work</span>