The Gnome Chemistry Utils provide C++ classes and Gtk+-2 widgets related to chemistry.They will be used in future versions of both Gnome Crystal and GChemPaint. I suggest app-sci/gchemutils.
Created attachment 37592 [details] gchemutils-0.2.5.ebuild
It would be better to use 0.2.7 because many memory leaks have been fixed. I am the author of this package an da new gentoo user (amd64). If I can help, tell me.
gchemutils has been in Portage for some time now.