What is the bond angle in a water molecule?

1 Answer
Nov 15, 2015


You can derive the approximate angle by knowing that the oxygen in water has four electron groups, giving it a tetrahedral electron geometry, and a bent molecular geometry.

From knowing that it has a tetrahedral electron geometry, but two lone pairs of electrons, one question should pop into your mind:

"Why does water not have a #109.5^@# H-O-H bond angle? "

It's because the two nonbonding #2p# orbitals on oxygen impose a spatial repulsion, bending together the two hydrogens and decreasing the bond angle, which is measured such that it is #<=180^@#.


(It is acceptable to just say #104.5^@#, but it is known to more decimal places than just one.)