There are several types of
Covalent Bonds.  We have
looked at water and hydrogen,
but some elements such as
oxygen and carbon can also
have a
double covalent bond.
This means that they can
share 4 electrons between the
two electron shells.  Carbon
also has the ability to form a
triple bond.

Just as covalent bonds are
stronger than ionic, a double,
or triple bond is even stronger.
Types of Covalent Bonds