Hi!
Just re-incarnation of old idea to support 3D image of chemical structures... I played a little bit with Kalzium in KDE 4 today and discovered molecule viewer which render molecules in Chemical Markup Language.
CML (http://cml.sourceforge.net) is open XML-based format so we could allow it on Commons and provide files repository for other projects (such as Kalzium).
There is also Java-based open source viewer JMol (http://jmol.sourceforge.net) including web browser plugin. With JMol we could dramatically enreach chemistry/biochemistry related pages in Wikipedia/Wikibooks/Wikiversity in same way as we support Ogg media files playback now.
Eugene.