Ionic bonding from a quantum mechanics point of view

In summary, the conversation discusses the question of the quantum nature of ionic bonds and how they differ from covalent bonds. It is mentioned that ionic bonding involves the transfer of electrons and is energetically favorable. The concept of molecular orbit theory and quantum mechanics are also brought up in explaining the nature of ionic bonds. The stability of ions compared to atoms is also a factor in understanding ionic bonding, which can be calculated using Koopmans theorem.
  • #1
Ron19932017
32
3
Hi all,

I have a question about the quantum nature of ionic bonds.

I know some ideas about molecular bonding which can combine two ground state of H atom
to get a bonding state and an anti-bonding state which in the case of H2 molecules it correspond to the covalent bonding (sharing of electrons).

However I did not know the quantum mechanics nature of ionic bond.
I know that from energetics, the "transfer" of electron is energetic favourable thus this is a bonding.
I also understand that the ionic bond is not absolute, it only means that the electron is likely to be found close to 1 atom in the case of simple 2-atom molecule.

Can someone kindly explain to me the quantum nature of ionic molecules ?
To be more specify, can molecular orbit theory (or any quantum theory) explain ionic bond?
 
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  • #2
Ionic bonding depends on one hand on the electrostatic attraction of the ions, which does not require quantum mechanical concepts and on the other hand an understanding of the stability of the ions as compared to the atoms, i.e. the calculation of the electron affinity and ionisation energy. These two quantities can be calculated to a good approximation using Koopmans theorem which states that the latter quantities are approximately equal to the energies of the highest unoccupied and occupied atomic orbitals, respectively.
 
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1. How does quantum mechanics explain ionic bonding?

Quantum mechanics explains ionic bonding as the result of electrostatic interactions between positively charged cations and negatively charged anions. In this theory, the electrons in each atom occupy specific energy levels known as orbitals, and when two atoms come together to form an ionic bond, the electrons are transferred between the atoms to achieve a more stable configuration.

2. What is the role of electron shells in ionic bonding?

Electron shells, or energy levels, play a crucial role in ionic bonding. In quantum mechanics, electrons are arranged in shells around the nucleus, and the electrons in the outermost shell determine the chemical properties of an atom. When forming an ionic bond, the outermost electrons of one atom are transferred to the outermost shell of another atom, resulting in the formation of ions and the bond between them.

3. How does the concept of quantum tunneling apply to ionic bonding?

Quantum tunneling allows electrons to "jump" between energy levels without having to pass through the energy barrier between them. In ionic bonding, this means that the electrons can easily move from one atom to another, even if they do not have enough energy to overcome the electrostatic repulsion. This phenomenon plays a crucial role in the formation and stability of ionic bonds.

4. Can quantum mechanics explain the strength of ionic bonds?

Yes, quantum mechanics can explain the strength of ionic bonds. The strength of a bond is determined by the difference in electronegativity between the atoms involved. In quantum mechanics, the electronegativity is related to the ionization energy and electron affinity of the atoms, which are both influenced by the electron configurations and energy levels. Therefore, the strength of an ionic bond is ultimately determined by the quantum mechanical properties of the atoms involved.

5. Do other factors besides quantum mechanics influence ionic bonding?

While quantum mechanics plays a crucial role in explaining ionic bonding, other factors can also influence the strength and stability of these bonds. For instance, the size and charge of the ions involved, as well as the crystal structure of the ionic compound, can affect the strength of the bond. Additionally, external factors such as temperature and pressure can also impact the stability of the bond. Therefore, while quantum mechanics is a fundamental aspect of ionic bonding, it is not the only factor at play.

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