Part 2. sp2
Hybridization of Carbon
sp2 hybridization is best illustrated
using ethene, C2H4. The carbon atoms in
this molecule are sp2 hybridized.
- Note that each carbon now has only three bonds, and that
the bonds about each carbon atom are coplanar, with 120o
bond angles throughout. Note also that the C-C bond is a double
bond, i.e. 4 electrons.
- To make these bonds, the s orbital and two of the p
orbitals of carbon are hybridized to for three equivalent
sp2 hybrid orbitals. (Remember for now that
this leaves one p orbital of carbon un-used.) Each sp2
orbital looks like the following. Use
the mouse to rotate the figure.
- When the three sp2 hybrids are arranged around
the carbon nucleus, we have:
- To form the C-C bond, an sp2 hybrid from one
carbon atom overlaps with that of the other, creating a
C-C single bond. This type of bond, resulting from the
end-on interaction of the two hybrid orbitals, is termed
a "sigma" bond. The other four sp2
hybrids are used to make single bonds with the hydrogens.
Remember that left over p orbital on each carbon atom? These
two now overlap to produce another bond between the carbon atoms.
This "pi" bind and the C-C sigma bond constitute the
double bond between the carbons. Note the extra electron density
between the carbons.
Back to part 1,sp3
On to part 3, sp