November 30, 2024, 05:32:46 AM
Forum Rules: Read This Before Posting


Topic: what is meant by priciple axis C4, C2?  (Read 8191 times)

0 Members and 1 Guest are viewing this topic.

Offline fishingcat

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
what is meant by priciple axis C4, C2?
« on: January 23, 2008, 10:48:39 AM »
HI there! it's my first time posting. i'm stuck on the Mulliken symbols. what is meant by priciple axis C4, C2? how is the notation C4, C2 be stated? why a1g is a very symmetric system in octahedral?

Offline Kryolith

  • Full Member
  • ****
  • Posts: 269
  • Mole Snacks: +19/-4
  • Gender: Male
Re: what is meant by priciple axis C4, C2?
« Reply #1 on: January 23, 2008, 05:43:38 PM »
what is meant by priciple axis C4, C2?

Benzene for example has one six-fold axis C6 and six twofold axes C2. If a molecule
has several rotational axes, then the one of them with the greatest value of n is called the principal axis. Was this your question actually?


Offline Alpha-Omega

  • Full Member
  • ****
  • Posts: 693
  • Mole Snacks: +360/-231
  • Gender: Female
  • Physical Inorganic Chemist
Re: what is meant by priciple axis C4, C2?
« Reply #2 on: January 23, 2008, 08:25:42 PM »
To explain A1g for an octahedral you need to look at the point groups for an octahedral molecule:

Here is a link to an Oh POINT GROUP:  http://www.webqc.org/symmetrypointgroup-oh.html

If you perform all the symmetry operations for A1g you can see that the object (bonding orbital) remains the same after each symmetry operation 1 = unchanged-there is no change and is completely symmetric.

Sponsored Links