ChemAxon's MarvinSketch Drawing Applet
This structure drawing applet is part of the Free Web package provided free for academic and non-commercial use by ChemAxon.com. Perhaps the coolest thing about this applet is the way that you can
- Import existing files (.mol, .pdb and others)
- Draw your own structures
- View the drawing in the 2-d and 3-d viewer applet (MarvinView), which show it as a formula that you can rotate
- View the structure in the molecular viewer (MarvinSpace) which allows you to view it as a model in traditional wireframe, ball and stick, spacefilling, and so on.