Trigonal Pyramidal: 3 bonding pairs, 1 lone pair.

This is an example of a Trigonal pyramidal molecule. It has angles all of which are 107°, and is a 3-dimensional structure. This example is of ammonia. Nitrogen, the central atom, has 5 valence electrons, 3 of which are bonded to hydrogen’s electrons. However, 2 of nitrogen’s valence electrons are not being used for bonding and create a lone pair. Examples: NH3, PCl3.

Trigonal Bipyramidal: 5 Bonding Locations and No Lone Pairs

This is an example of a Trigonal bipyramidal molecule. It has 120°, 180°, and 90° angles and is a 3-dimensional structure. This particular molecule is Phosphorus pentachloride. The lewis dot structure is composed of 40 valence electrons 5 bonding locations and 0 lone pairs on the central atom. Examples: PF5, SF4.

See Saw : Four Bonding Locations and One Lone Pairs

This is an example of the seesaw molecule that contains one lone pair. The lone pair is located on the right side of the molecule, forcing the other atoms to create a 90 degree angle between them in a 2-dimensional structure. This particular molecule is SULFURIC FLORIDE, SF4.

Octahedral: No Lone Pairs, 6 Bonding Locations

This is an example of a octahedral molecule that contains no lone pairs. This is a Sulfur hexaflouride molecule, SF6, which contains 48 valence electrons to use for the lewis dot structure. When the lewis dot structure is drawn there are six bonding locations and no lone pairs on the central atom. This type of configuration would give you a octahedral geometry. The angles are 90 degrees all around except for opposite atoms, which would be 180 degrees. Other octahedral molecules would be SCl6, SeF6, and SeBr6. Click on the top picture to see the rotation of the molecule.