XDrawChem is described as 'free software program for drawing chemical structural formulas, available for Unix and Mac OS. It is distributed under the GNU GPL. In Microsoft Windows this program is called WinDrawChem' and is an app in the Education & Reference category. There are nine alternatives to XDrawChem for a variety of platforms, including Windows, Mac, Linux, iPhone and iPad. The best alternative is Avogadro, which is both free and Open Source. Other great apps like XDrawChem are Marvin (Free), BKchem (Free, Open Source), JChemPaint (Free, Open Source) and ACD/ChemSketch (Free Personal).
Marvin suite is a chemically intelligent desktop toolkit built to help you draw, edit, publish, render, import and export your chemical structures and as well as allowing you to convert between various chemical and graphical file formats.
ACD/ChemSketch is a chemically intelligent drawing interface that allows you to draw almost any chemical structure including organics, organometallics, polymers, and Markush structures. Use it to produce professional looking structures and diagrams for reports and publications.