Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dipole Dipole and Lewis Dot structes

  1. Sep 20, 2005 #1
    Why doesn't HOOH dipole dipole forces?

    I read that if a molecule has an Oxygen atom, it's likely to have dipole forces. This one only has Dispersion forces.

    Also, why does the Lewis structure of this molecule NOT look like this:

  2. jcsd
  3. Sep 21, 2005 #2
    Because the dipoles cancel out. (e.g., [tex] CO_2 [/tex] is nonpolar, but contains polar bonds).

    The component dipole moments of [tex] H_2O_2 [/tex] simply cancel out, and it has no net dipole moment.
    You see, hydroxyl groups contain a partially positively charged hydrogen and a partially negatively charged oxygen.

    Draw the direction of each dipole moment, and you will have two antiparallel H -|--> O equal in magnitude but opposite in direction (as vectors). As in vector addition, these two dipole moments will cancel each other out (you have a zero vector for net dipole).
    Consider formal charge, and the usual valence of oxygen atoms. (http://www.westga.edu/~chem/courses/chem1212slattery/contents/chapter8-all/img031.gif [Broken])
    (Hint: Oxygen | [itex] 1 s ^2 2 s^2 2 p^4 [/itex] )
    Last edited by a moderator: May 2, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook