The molecular geometry of water is tetrahedral, but its molecular shape is bent. Is this contradictory?

1 Answer
Nov 24, 2015

Answer:

The bonding and non-bonding electron pairs arranged about oxygen in the water molecule assume the shape of a tetrahedron to a first approximation.

Explanation:

About the #O# atom in the water molecule there are 2 non-bonding lone pairs, and 2 bonds to hydrogen. VSEPR tells us that the most energy stable disposition of these electron pairs is as a tetrahedron. But we describe molecular shape in terms of the bound atoms: that is as a "bent" #H-O-H# structure where the lone pairs compress the #/_OH_2# bond angle.