Delocalization in metals and conjugated systems

  • Thread starter Thread starter Deadevil
  • Start date Start date
  • Tags Tags
    Metals Systems
Click For Summary

Discussion Overview

The discussion centers around the concept of delocalization in both organic and inorganic chemistry, specifically contrasting delocalization in conjugated systems with that in metals. Participants explore the implications of electron behavior in these different contexts, addressing theoretical and conceptual aspects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Faisal expresses confusion about the concept of delocalization, noting that it is typically associated with conjugated systems in organic chemistry, while also questioning its occurrence in metals without double bonds.
  • One participant clarifies that delocalization refers to electrons not being bound to a single atom and can occur in both conjugated pi systems and metals, despite the differences in these systems.
  • Another participant suggests that in conjugated systems, delocalization arises from the ground electron configuration, while in conductors, valence electrons must overcome a band gap to delocalize.
  • A subsequent reply corrects the previous statement, asserting that conductors do not have a band gap, which is a characteristic of their conductive properties.
  • One participant acknowledges the correction and mentions the possibility of small band gaps in conductors that may be populated at certain temperatures, questioning whether this is merely a semantic issue.
  • Another participant discusses that delocalization occurs when multiple equivalent resonance structures can be drawn, noting that in metals, the abundance of orbitals relative to electrons allows for more bonding possibilities.
  • One participant posits that Lewis resonance structures represent delocalization, suggesting that bond breakage is only a representation and that metals exist as hybrid structures of these resonance forms.
  • A later reply identifies this perspective as aligning with Pauli's resonating valence bond description of metallic bonding.

Areas of Agreement / Disagreement

Participants express varying interpretations of delocalization, with some agreeing on the fundamental concept while others debate specific details regarding band gaps and resonance structures. The discussion remains unresolved with multiple competing views presented.

Contextual Notes

Participants reference concepts such as band gaps, resonance structures, and the behavior of electrons in different materials, but there are limitations in the clarity of definitions and assumptions regarding these terms.

Deadevil
Messages
21
Reaction score
0
Hi Fellow Members,
I am a bit confused about delocalization concept. Since, in organic chemistry we have been told that delocalization only exits between conjugated systems but in inorganic chemistry there is delocalization of electrons in metals with no double bonds. Isn't it confusing, is there a difference between both delocalization. Please help me out.

Thanks
Faisal
 
Chemistry news on Phys.org
Delocalization means electron is not bounded to an atom, but can travel much further.

It is possible in conjugated pi systems, it is possible in metals. These are very different systems, but the idea remains the same.
 
My limited understanding of each phenomenon is that in a conjugated system the ground electron configuration leads to delocalization whereas in a conductor the valence electron(s) need(s) to overcome the band gap in order to delocalize.
 
Not that I feel confident about these things either, but there is no band gap in conductors, that's why they are conductors.
 
Borek said:
Not that I feel confident about these things either, but there is no band gap in conductors, that's why they are conductors.

Could be, I will do some reading later in the evening. I thought that conductors simply have very small band gaps which are populated at reasonable temperatures according to the Boltzmann distribution. Maybe that is just semantics?

EDIT: Sorry, Borek is correct. Conductors have overlap of valence and conduction bands. See: http://hyperphysics.phy-astr.gsu.edu/hbase/solids/band.html
 
Last edited:
Yanick said:
EDIT: Sorry, Borek is correct.

You don't have to be sorry about me being correct :-p

But I am wrong often enough to be happy when I get something right :wink:
 
Delocalization always occurs when you can draw several equivalent resonance structures. In organic chemistry, this usually only happens for the pi system, although there are exceptions like e.g. CH5+.
In metals, boron compounds etc. delocalization is more commonplace as metals tend to have more orbitals than electrons, so that more bonding possibilities become possible.
What also matters, i the low electronegativity of metals. This allows for the possibility to include ionic resonance structures, so that not only compounds with alternating bonds will show delocalization.
 
Ok, it means that lewis resonance structure represents only delocalization. bond breakage is only for representation. metal exists as a hybrid structure of lewis resonance structures. Delocalization in metal is due to the increased density of electron in metal. Please Let me know if I am correct.

Thanks
 
Yes, this is basically Pauli's resonating valence bond description of metallic bonding.
 
  • Like
Likes   Reactions: 1 person

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
5
Views
2K
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
16K
Replies
1
Views
3K