Molecular geometry tells the shape the molecule.  The shape of the molecule is important because the shape tells us something about how that molecule is going to interact with other molecules, like itself or different. 

The following material will lead you through some basic molecular geometries.  You will need to download a VRML player to be able to look at the molecular geometries.  It is a free download.

When you have the player installed you are ready to go.  Choose study on the control buttons.

Below is a listed of the molecular geometries and molecules available.

Electron Pair Arrangement	Molecular Geometry	Lewis Structure	Molecule
Two electron pairs	Linear		HCN
Three electron pairs	Trigonal Planar		SO3
	Angular		SO2
Four electron pairs	Tetrahedral		CH4
	Trigonal Pyramidal		NH3
	Angular		H2O
Multi-centered Molecules	C- trigonal planar, O- trigonal planar		Formaldehyde
	C - tetrahedral, C - trigonal planar, O - trigonal planar		Acetaldehyde
	C- tetrahedral, O - angular		Methanol