Energy Bands and Molecular Orbitals

In summary, The relationship between MO and Energy Bands is that Energy Bands occur as the number of MO increase in a crystal structure, due to the interlinking of various atoms. However, the behavior of different elements in terms of conduction can be confusing, as seen with K and Si. To gain a clearer understanding, it is recommended to study Bloch's theorem and do model calculations for one dimensional systems.
  • #1
ABhattacharya
2
0
Hello, a newbie here. I need to understand the relationship between MO and Energy Bands.

Although i have searched and researched about this topic in Google, but i am yet to understand this part clearly.

It is said that Energy Bands occur as the number of MO increase due to the various atoms that are interlinked in a crystal structure.

But i can't help but wonder.
While K has its σ state fully filled and its σ* state empty, and yet behaves as a conductor
But Si has ∏px and ∏py states partially filled which means when bands form, Si should have some bands which are partially filled and hence should be good conductors while Na should behave more of a semiconductor way... but it is just the opposite. Why?
 

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  • #2
The diagram you show seems to be for diatomic molecules while the band structure refers to infinitely large crystals. Why do you think the two are comparable?
 
  • #3
DrDu said:
The diagram you show seems to be for diatomic molecules while the band structure refers to infinitely large crystals. Why do you think the two are comparable?

Then what should i do to get a clearer picture of the MO and Energy Band conduction??
 
  • #4

FAQ: Energy Bands and Molecular Orbitals

What are energy bands and molecular orbitals?

Energy bands and molecular orbitals are terms used in chemistry and physics to describe the distribution of energy levels within a material or molecule. Energy bands refer to the range of energy levels that electrons can occupy in a solid material, while molecular orbitals refer to the specific energy levels that electrons can occupy in a molecule.

How are energy bands and molecular orbitals related?

Energy bands and molecular orbitals are related in that they both describe the energy levels available for electrons in a material or molecule. However, energy bands refer to a larger range of energy levels, while molecular orbitals refer to specific energy levels within that range for a particular molecule.

What is the difference between a valence band and a conduction band?

A valence band is the highest energy band that is fully occupied by electrons in a material, while a conduction band is the band just above the valence band that is partially filled or empty. The energy gap between the two bands determines the material's conductivity, with larger gaps leading to insulating properties and smaller gaps leading to conducting properties.

How do energy bands and molecular orbitals affect the properties of materials?

The distribution of energy levels in a material, as described by energy bands and molecular orbitals, can greatly influence its properties. For example, the size of the energy gap between the valence and conduction bands can determine a material's conductivity, while the overlap of molecular orbitals can affect a molecule's chemical reactivity.

Can energy bands and molecular orbitals be manipulated?

Yes, energy bands and molecular orbitals can be manipulated by changing the conditions of a material or molecule. For example, applying an external electric field can shift the energy levels within a material, while altering the arrangement of atoms in a molecule can change the distribution of molecular orbitals. This manipulation can be used to control the properties of materials and molecules for various applications in technology and science.

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