# Why is water unusual?

For such a small molecule, water has an exceptionally high boiling point, and this may be traced to the polarity of the $O - H$ bond.
If you compare the boiling points of other small molecules, i.e. $N {H}_{3}$, $C {H}_{4}$, ${H}_{2} S$, to that of water, it is very clear that the $100$ ""^@C normal boiling point is exceptionally high. Because the oxygen hydrogen bond is polar, i.e. ""^(delta+)H-stackrel(delta-)O-H^(delta+)water molecules engage in extensive intermolecular hydrogen bonding, and this substantially elevates the boiling point.