Question

What is the electron pair geometry for a water molecule, `H_2O`?

Answer 1

The geometry of electron pairs in water, bonding and non-bonding, is tetrahedral to a first approximation.

Explanation:

Around each oxygen atom there are 2 lone pairs, and 2 bonding pairs of electrons to form the `O-H` bonds. `/_H-O-H` is compressed from the ideal tetrahedral angle of `109.5` `""^@` to approx. `104.5` `""^@` because the lone pairs are larger and more diffuse than a localized bonding pair, and therefore more likely to influence structure.

The geometry of valence electron pairs around oxygen is thus tetrahedral. But we describe the geometry of the water molecule as bent