Drawing Chemical Structures
Draw your own chemical structures with this Demonstration.[more]
First, select a structure and then click the "add" button. To move an object, click its far edges and drag it. To rotate an image, click nearer to its center and spin it to the desired angle.
The "undo" button deletes the last component added.
To insert an element, click the buttons at the top and drag the symbol anywhere.[less]
 Wikipedia. "Chemical Formula." (Mar 29 2012) http://en.wikipedia.org/wiki/Chemical_formula.
 Wikipedia. "Skeletal Formula." (Feb 23 2012) http://en.wikipedia.org/wiki/Skeletal_formula.