ChemDraw is described as «Communicate with the natural language of chemical structures, biological pathways, and models» and is an app in the education & reference category. There are more than 10 alternatives to ChemDraw for a variety of platforms, including Windows, Linux, Mac, iPhone and iPad. The best alternative is Chemaxon Marvin, which is free. Other great apps like ChemDraw are ChemDoodle, BKchem, XDrawChem and Gnome Chemistry Utils.