Difference ionic and covalent bonds

Click For Summary
SUMMARY

The discussion clarifies the distinctions between ionic and covalent bonds, emphasizing that covalent bonds involve shared electrons around bound nuclei, while ionic bonds are characterized by the electric force between ions. It is established that pure covalent bonds exist only between identical atoms, and pure ionic bonds are debated in terms of their existence. Most bonds are a hybrid of both types, with quantum mechanics (QM) indicating that a bond is ionic if the electron probability density is significantly greater around one nucleus. Linus Pauling's "The Nature of the Chemical Bond" is recommended for further insights into the potential energy curves of these bonds.

PREREQUISITES
  • Understanding of basic chemistry concepts, including atomic structure and bonding.
  • Familiarity with quantum mechanics principles, specifically Linear Combination of Atomic Orbitals (LCAO) and Molecular Orbitals (MO).
  • Knowledge of Linus Pauling's theories on chemical bonding.
  • Ability to interpret potential energy curves in chemical bonding contexts.
NEXT STEPS
  • Study Linus Pauling's "The Nature of the Chemical Bond" for in-depth analysis of ionic and covalent bonds.
  • Explore quantum mechanics applications in chemistry, focusing on LCAO and MO theories.
  • Research the concept of electronegativity and its role in bond character determination.
  • Investigate the potential energy curves for various chemical bonds to understand their behavior at different distances.
USEFUL FOR

Chemistry students, educators, and researchers interested in the nuances of chemical bonding, particularly those exploring the quantum mechanical aspects of ionic and covalent interactions.

jostpuur
Messages
2,112
Reaction score
19
According to chemistry books the ionic and covalent bonds are a different thing. In covalent bonds the electrons share the same space around the bound nuclei, while in ionic bonds two ions are bound by the electric force between the ions.

However, the truth is that the wave functions of the electrons are spread onto the surroundings of the both nuclei anyway, and I'm left unable to understand what the ionic bond is supposed to mean.
 
Physics news on Phys.org
My understanding is that you never get bonds that are perfectly ionic.

Claude.
 
It is a question of degree. Pure covalent bonds can only exist between identical atoms (such as a homonuclear diatomic molecule), while one could argue a long time whether pure ionic bonds can exist. [Edit: the other Claude was faster than me on this last point.]

For most molecules, a bond will be somewhere between covalent and ionic. When the sharing is more or less equal, then we call that a covalent bond; when it is very unequal, ionic. In QM (LCAO-MO), you would call a bond ionic if the corresponding bonding orbital leads to a much greater probability density of the electron around one nucleus than the other.
 
  • Like
Likes   Reactions: 1 person
I've consulted several textbooks looking for 'quantum theory of the ionic bond' (let's say in CsF). Turned up nothing. So I'm assuming that the 'ionic bond' doesn't exist.

EDIT: Just saw post #3.
 
You could have a look in Linus Pauling "The nature of the chemical bond"
Usually you can draw two potential energy curves, even for bonds between equal atoms.
One of the curves is predominantly ionic, the other one covalent.
At large distances, the ionic rises like 1/R and lies above the covalent one. In molecules which are
covalent at the equilibrium distance, the ionic curve lies always above the ionic one, in those molecules which are
predominantly ionic at equilibrium distances, the two curves nearly intersect at some larger distance.
There are pictures in Paulings book and good explanations.
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
6
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 6 ·
Replies
6
Views
15K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
3
Views
2K