1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Water molecule

  1. Oct 24, 2007 #1
    Why does water angled 104.45° ?
     
  2. jcsd
  3. Oct 24, 2007 #2

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Because the O-atom is sp3 hybridized, and the repulsion from non-bonding electron pairs is greater than that from bonding electron pairs.
     
  4. Oct 25, 2007 #3

    jim mcnamara

    User Avatar
    Science Advisor
    Gold Member

    Gokul - good answer. But it doesn't totally explain the divergence of the 104.45 degree angle from the expected 109.47 degree angle - this explains why (I think):

    http://xnet.rrc.mb.ca/rcharney/The water molecule.htm
     
  5. Oct 26, 2007 #4

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Jim, the divergence was traditionally explained in terms of a greater delocalization of the lone pairs causing the bond angle to be smaller that the symmetric angle - this is what I stated above. However, the information in your reference suggests there is now good reason to believe that in fact, the 2s orbital is unhybridized and the 105 deg = 90 deg + steric repulsion from H atoms.

    Thanks for the link.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?