MarvinSketch is one of tools of the Marvin which is a poweful & cross-platform collection of Java tools for drawing, displaying and characterizing chemical structures, substructures and reactions. It has a rich (and growing) list of editing features, is chemically aware and is able to call ChemAxon’s structure based calculation plugins for structures on the canvas.If you often need to draw chemical diagram,I strongly recommend MarvinSketch to you.

marvinsketch

Download(requires register) :http://www.chemaxon.com/marvin/download-user.html

see more about MarvinSketch or Marvin :http://www.chemaxon.com/product/msketch.html