Hybridization, Sigma and Pi Bonds Model Kit

Styrofoam spheres representing sp, sp2, sp3 hybridized carbon atoms and hydrogen atoms can be linked by ellipsoidal sigma bonds. Un-hybridized p orbitals can be attached and linked with styrofoam bonds to represent pi bonds in double or triple bonds, delocalized electrons, or aromatic ring structures.  The models are a good visualization of electron density located between two nuclei, a sigma bond, and electron density located above and below two nuclei, a pi bond.

Methane, ethane, ethene, acetylene, butadiene, and benzene are some of the molecules that can be represented using this model kit.

Half of the p orbitals are marked with white circles in case the instructor wants to indicate the sign of the wave function for electrocyclic reaction modeling. 

The models are helpful, but the display of the models should be accompanied by a robust set of visual images representing valence bonding orbital overlap, sigma bonds, and pi bonds. A set of PowerPoint slides is available to accompany the models for use in general chemistry.

Curriculum Notes 

This model set can be used in the general chemistry curriculum when multiple bonding or electron delocalization is being discussed. The applications in an organic chemistry class are manifold.

Lead Time 
One day of lead time is required for this project.
Procedure 

This molecular model kit (circa 1965) is large enough to be visible for students in a medium size lecture hall (n = 150). The models will not be visible to students in the back third of a 490 seat lecture hall.  In a large lecture hall, use of video cameras to show large images of the models is recommended.

© Copyright 2012 Email: Randy Sullivan, University of Oregon Chemistry Department and UO Libraries Interactive Media Group