Students can use this applet to explore different 3-D objects. Different objects can be chosen, rotated, and viewed from a variety of sides. [Requires Java.]

A colorful picture of two partially clear 3D shapes.

This site from the Department of Chemistry at Washington University is a nice site in that it gives you a graphical look at the arrangement of electron pairs. The plug-in CHIME will let you see the 3-D molecules, but it is good even if...