Covalent Compounds: More hybridization

The previous section introduced hybridization and how it explains geometry found in compounds.  The example of sp3 for an octet of electrons (four bonding pairs) of a central atom was used in the introductory section because this hybridization is probably the one most often found in compounds.

There are other numbers of electrons that exist around central atoms that the student needs to know. The student will be directed to websites for additional information.

Before beginning this discussion, open a second window.  Copy and paste, http://en.wikipedia.org/wiki/Hybrid_orbitals , in the address bar. Notice the two graphics on the right side of the page.  Scroll down to the section titled “Types of hybridization”.  Note the three types of sp hybrids, the shapes and molecular formulae associated with each.  These hybrids are found in molecules of organic compounds.

Scroll down to the section “Hybridization and molecule shape”.   Carefully examine the information in the table.  The first column lists possible hybrids depending on the number of bonding pairs.  The first entry, AX2, has 2 bonding pairs about the central atom A.  Like wise AX3 has three bonding pairs about the central atom A.  AX4 was discussed in the section titled Covalent Compounds: “Molecular Orbitals (Hybridization)”

Open a third window.  Copy and paste, http://www.chem.ufl.edu/~myers/chm2045/shapes.htm , in the address bar.  Look at the examples on this page and compare them to the designations (AX2, AX3, etc) on the hybridization table of the second window.

The next set of web sites provides another view of this information.  Note the change in geometry when there are nonbonded electron pairs in the molecule.

3 Groups/Pairs Around the Central Atom

4 Groups/Pairs Around the Central Atom

5 Groups/Pairs Around the Central Atom

6 Groups/Pairs Around the Central Atom

This information will be presented again in subsequent sections when appropriate.  At this time just be aware of hybridization and the role it has in molecular structure.  Also be aware of the effect of non-bonded electrons on molecular structure.