4.6 Hybrid Orbitals

  • Orbitals overlap, may form hybrid orbitals of equal length.
  • Form to satisfy VSEPR geometry.
  • Hybrid orbitals form by combining orbitals with different shapes in a process called hybridization.

Types of Hybrid Orbitals

Chart for Hybrid Orbitals

Sigma vs. Pi Bonds

  • Sigma bonds

    • Bonds that are formed when 2 orbitals overlap end to end
    • (s, p, sp hybrid)

  • Pi Bonds

    • Bonds that form when two parallel orbitals overlap
    • Occur during double/triple bonds.

    Bonding Types

Example Test Questions

  • For the molecule NH3:
    • Draw the Lewis Structure, identify sigma and pi bonds (consider formal charge)
    • Draw the VSEPR diagram
    • List the AXE #, steric #, basic geometry, molecular geometry
    • Determine the hybrid orbitals, identify sigma and pi bonds
    • Must match basic geometry (tetrahedral is sp3, trigonal planar is sp2, linear is sp, etc)
    • Bonds require unpaired electron
    • Pi bonds must be p orbitals (not hybridized)
    • Draw orbital diagram

Steps:

  1. Write electron configuration

  2. Draw diagram showing valence electrons

  3. Determine is any promotion is required, if so, draw another diagram

    1. keep in mind sigma and pi bonds

  4. Hybridize by moving electrons, draw a full orbital diagram showcasing the bonding and hybridization