# Bent molecular geometry of water

Could you please explain how the bent molecular geometry of water is due to hydrogen bonding? I was under the impression that it was because of the lone pairs (VSEPR Theory).

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Your impression is correct. The bend in the water molecule doesn't have anything to do with hydrogen bonding, as evinced by the fact that isolated water molecules retain their bent geometry. –  Richard Terrett Dec 23 '12 at 0:34
Okay thanks, I missed the question on the test which is why I was perplexed. –  LanguagesNamedAfterCofee Dec 23 '12 at 0:39

The slightly more advanced explanation comes from molecular orbital theory. Oxygen's valence electrons are all $2\text{p}$ electrons; hydrogen's electron is $1\text{s}$. The only way to mix those orbitals to get enough bonding orbitals is by using two $\text{sp}^3$ hybrid orbitals to generate the two bonds. The $\text{sp}^3$ orbitals are arranged in a tetragonal geometry.