Polar covalent bonds are a particular type of covalent bond.
In a polar covalent bond, the electrons shared by the
atoms spend a greater amount of time, on the average, closer to the Oxygen
nucleus than the Hydrogen nucleus. This is because of the geometry of the
molecule and the great electronegativity difference between the Hydrogen
atom and the Oxygen atom.
The result of this pattern of unequal electron association
is a charge separation in the molecule, where one part of the molecule,
the Oxygen, has a parital negative charge and the Hydrogens have a partial
positive charge.
You should note this molecule is not an ion because there is no excess of proton or electrons,
but there is a simple charge separation in this electrically neutral molecule.
Water is not the only molecule that can have polor
covalent bonds. Examples of other molecules that have polar covalent bonds
are Peptide bonds and amines .
The biological consequence of polar covalent bonds is that
these kinds of bonds can lead to the formation of a weak bond called a hydrogen bond.
return to nonpolar covlent bond
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