Is XeF4 violating the octet rule?

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SUMMARY

The discussion centers on the octet rule and its exceptions in second-period elements, specifically highlighting xenon tetrafluoride (XeF4) and superoxide (O2-). Participants confirm that beryllium (Be) and boron (B) can bond with fewer than eight electrons, while XeF4 exhibits a stable configuration despite having more than eight electrons around xenon. The conversation also touches on sulfur (S8) and boranes, noting that larger atoms can accommodate non-ideal bond angles, which contributes to their ability to form stable structures without adhering strictly to the octet rule.

PREREQUISITES
  • Understanding of Lewis structures
  • Familiarity with the octet rule
  • Knowledge of molecular geometry and bond angles
  • Basic concepts of quantum chemistry
NEXT STEPS
  • Study the Lewis structure of xenon tetrafluoride (XeF4)
  • Research the properties and bonding of superoxide (O2-)
  • Explore Wade's rules for constructing boranes
  • Investigate the molecular geometry of sulfur (S8) and its implications
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Chemistry students, educators, and researchers interested in molecular bonding, exceptions to the octet rule, and advanced concepts in quantum chemistry.

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Is there any violation of the octet rule in the second period elements?
-scott
 
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Yes, beryllium typically bonds with 4 electrons (ie BeF2) and boron with 6 (BF3). Flourine is often involved in bonds that have more than 8 electrons (XeF4).
 
Also the superoxide radical, O2 with an extra electron. It's found in biological systems.
 
movies said:
Also the superoxide radical, O2 with an extra electron. It's found in biological systems.

Just to add, this is a biradical, with an unpaired electron on each oxygen atom.

~H
 
Hootenanny said:
Just to add, this is a biradical, with an unpaired electron on each oxygen atom.

~H

You mean singlet oxygen? That's different. In that case you haven't added an electron, in superoxide you have one more electron than you do in the regular oxygen molecule.

Anyway, I think that I was wrong. You can draw a Lewis structure for superoxide radical where you have 3 lone pairs on one O and two lone pairs plus one electron on the other, with a bond between the two. In that resonance structure it's not an octet rule violation. My mistake.
 
What about S8?
-scott
 
scott_alexsk said:
What about S8?
-scott

S is in the 3rd period...

Also, S8 is a ring of sulfur atoms, so there is no violation.
 
Why is octet configuration stable?
 
It just is.

Careful quantum calculations show that there is a deep local minimum of the potential energy for filled ns and np subshells. There are also shallow local minima at half-filled subshells. These are just the results of very complex calculations and it's hard to simplify things - in my opinion - to any considerable extent without being "a little" dishonest.
 
Last edited:
  • #10
Nitrogen does interesting stuff as well - like in hydrazine
 
  • #11
Gokul43201 said:
It just is.

Careful quantum calculations show that there is a deep local minimum of the potential energy for filled ns and np subshells. There are also shallow local minima at half-filled subshells. These are just the results of very complex calculations and it's hard to simplify things - in my opinion - to any considerable extent without being "a little" dishonest.
thanks Gokul
I would request you to explain the difference between a wave and a particle? How would you describe the behaviour of an electron as a wave(qualitatively)?
 
  • #12
Malay, this question is fairly unrelated to the rest of this thread.

I have a couple of suggestions for you.

1. Read post #3 in the Physics FAQ thread : https://www.physicsforums.com/showthread.php?t=104715
It does not directly answer your question, but addresses some part of it.

2. If you still have something you want to ask, start a new thread in the appropriate Physics subforum - General Physics will work - and ask your question there.
 
  • #13
Gokul43201 said:
Malay, this question is fairly unrelated to the rest of this thread.

I have a couple of suggestions for you.

1. Read post #3 in the Physics FAQ thread : https://www.physicsforums.com/showthread.php?t=104715
It does not directly answer your question, but addresses some part of it.

2. If you still have something you want to ask, start a new thread in the appropriate Physics subforum - General Physics will work - and ask your question there.
Thanks for your help
 
  • #14
Why does oxygen not form o8, since it is in the same family as sulfur?Also what about the Boranes?
 
  • #15
One reason is the steric strain. Larger atoms like S, Se, Te can more easily accommodate non-ideal bond angles that are necessary to make the ring structures.

What about the boranes? Yes, they do not satisfy octets in general (see post#2, by cesium). Also look into Wade's rules for constructing boranes with n electron pairs.
 
  • #16
Does that mean that XeF4 follows the octet rule?
 
  • #17
try and draw out the structure of XeF4 and count the electrons. If you draw the correct structure your question should be answered.
 

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