If you like us, please share us on social media.
The latest UCD Hyperlibrary newsletter is now complete, check it out.

ChemWiki: The Dynamic Chemistry E-textbook > Wikitexts > UC Davis > UCD Chem 124A: Kauzlarich > ChemWiki Module Topics > MO Theory: CO

MO Theory: CO

Molecular orbital (MO) theory can be used to describes the bonding in CO.  CO bonding is specifically based on a heteronuclear Molecular Orbital theory. The different types of energy levels and overlapping of orbitals will be discussed through MO theory for CO.    


The goal of MO theory is to allow us to produce a diagram that will give us information about the allow energy bonding between carbon and oxygen. 

Please use only heading 2 and lower, heading 1 is ugly and is avoided.  In this section, give a short introduction to your topic to put it in context. The module should be easy to read; please reduce excess space, crop figures to remove white spaces, full justify all text, with the exception of equations, which should use the equation command for construction (see FAQ).

MO Diagram and Calculation


MO CO Diagram.jpg

For carbon monoxide, both carbon and oxygen uses sp because two things are attach to both carbon and oxygen.  For example, carbon is connected to one lone pair (1 thing) and connected to oxygen (1 thing).  So there are a total of two things attached to oxygen.  Sp arrangement of its hybridized lopes are linear, so it is possible for one lone pair to be occupied in one of lopes, while the other is used for overlapping. 

Rename to desired sub-topic. This is where you put the core text of your module. Add any number of headings necessary for your topic. Try to reduce unnecessary discussion and get to the point in a terse, yet informative, manner possible.

Analyzing MO for CO

The bonding order of CO is 3.  It would make sense, carbon monoxide is triple bonded between carbon and oxygen.  From the diagram we see that it is bonded by two pi overlaps and one sigma overlap.  

Rename to desired sub-topic. You can delete the header for this section and place your own related to the topic. Remember to hyperlink your module to other modules via the link button on the editor toolbar.


  1. Housecroft, Catherine. Inorganic Chemistry. England: Pearson Education Limited, 2005.
  2. McQuarrie, Donald A., and John D. Simon. Physical Chemistry: a Molecular Approach. Sausalito, CA: University Science, 1997. Print

Outside Links

  • This is not meant for references used for constructing the module, but as secondary and unvetted information available at other site
  • Link to outside sources. Wikipedia entries should probably be referenced here.


What does it mean by sigma and pi overlaps?

-sigma is connected by sp hybridization overlap, while pi are overlap by the pz and py overlaping.

Why is the oxygen 2p orbitals are lower in energy than carbon 2p orbitals?

-because oxygen is more electronegative and is more stable in energy, so is lower in energy.

Is it possible for [CO]2- to exist?

-It is not possible to exist, because two more electrons will be occupied in the antibonding orbital. 

Be careful not to copy from existing textbooks. Originality is rewarded. Make up some practice problems for the future readers. Five original with varying difficulty questions (and answers) are ideal.


  • Name #1 here (if anonymous, you can avoid this) with university affiliation

You must to post a comment.
Last modified
10:16, 2 Oct 2013



(not set)
(not set)

Creative Commons License Unless otherwise noted, content in the UC Davis ChemWiki is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. Permissions beyond the scope of this license may be available at copyright@ucdavis.edu. Questions and concerns can be directed toward Prof. Delmar Larsen (dlarsen@ucdavis.edu), Founder and Director. Terms of Use