This is a german diagram that visualizes the <a href="https://en.wikipedia.org/wiki/Haber_process" class="extiw" title="w:Haber process">Haber process</a>.
<a href="//commons.wikimedia.org/wiki/User:Sven" title="User:Sven">Sven</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>