Objectives

1. For any pair of atomic orbitals on two atoms, determine whether there is no interaction or a net interaction between the two orbitals.
2. For orbitals where a net interaction occurs, determine whether the interaction produces sigma, pi, or delta bonding/antibonding orbitals.

Use the controls on the left to select the orbital on the left atom and the orbital on the right atom. Then use the controls to move the orbitals close together so that overlap occurs. Carefully examine the overlap and determine whether the two orbitals interact (bonding/antibonding orbitals are formed) or do not interact (orbitals are nonbonding).

The green color represents an area where the wave function has a positive sign; the red color represents an area where the wave function has a negative sign.

NOTE: In this exercise, the two atoms approach each other along the z-axis. In other molecules, especially molecules containing more than two atoms, atoms may approach from other directions, and consequently the orbitals that interact will differ from those in this example. For this reason, do not attempt to memorize orbital combinations; it is necessary to examine the overlap behavior for each molecule individually.

Part 1

It is possible to examine all 45 combinations of orbitals (3s, 3p_x, 3p_y, 3p_z, 3d_z², 3d_xz, 3d_yz, 3d_xy, and 3d_x²-y²). For the purpose of this exercise, however, it is only necessary to examine the following combinations:

1. 3s and 3p_z
2. 3s and 3p_y
3. 3p_x and 3p_y
4. 3s and 3d_z²
5. 3p_y and 3d_yz
6. 3p_y and 3d_xy
7. 3d_yz and 3d_yz
8. 3d_xy and 3d_xy
9. 3s and 3d_yz
10. 3d_x²-y² and 3d_x²-y²

Part 2

Display the 3p_y orbital on the left atom, and systematically examine the overlap of this orbital with all possible orbitals on the right atom (there are nine orbitals). For each pair of orbitals, indicate whether there the orbitals are nonbonding (n), sigma bonding/antibonding (σ/σ^*), pi bonding/antibonding (π/π^*), or delta bonding/antibonding (δ/δ^*).

Contributors

• Prof. David Blauch (Davidson College)

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