What makes a material an insulator?

In summary: Basically, a material has a band gap if it doesn't have any electron vacancies. A material can have a band gap if it has a certain number of electron vacancies, but usually there is a specific energy where the number of vacancies is so high that it could support electrons. In summary, metals have a delocalized electron network that allows them to have a high electrical and thermal conductivity. Materials that don't have a band gap are semiconductors and insulators.
  • #1
Fig Neutron
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(This is a two part question.)

Ok, so I have been trying to find what property of a material determines if it is a good conductor or not. I'm hoping to go beyond just if it can conduct electricity or not. One of the explanations I have found is the length of the band gap. Is this right or have I missed something?

Regardless of whether this is the answer for the first question, what causes a band gap? What is in this gap or is it empty? And why can't an electron exist within this gap?
 
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  • #2
It is easier to study conducting metals by contrast.

https://en.wikipedia.org/wiki/Metal#Electrical said:
The electrical and thermal conductivities of metals originate from the fact that their outer electrons are delocalized. This situation can be visualized by seeing the atomic structure of a metal as a collection of atoms embedded in a sea of highly mobile electrons. The electrical conductivity, as well as the electrons' contribution to the heat capacity and heat conductivity of metals can be calculated from the free electron model, which does not take into account the detailed structure of the ion lattice.
351px-Band_filling_diagram.svg.png

Filling of the electronic states in various types of materials at equilibrium. Here, height is energy while width is the density of available states for a certain energy in the material listed. The shade follows the Fermi–Dirac distribution (black = all states filled, white = no state filled). In semimetals the Fermi level EF lies inside at least one band. In insulators and semiconductors the Fermi level is inside a band gap; however, in semiconductors the bands are near enough to the Fermi level to be thermally populated with electrons or holes.
I apologize if this stuff is a bit difficult for B level, but you asked specifically about the gaps.
 

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Thanks, I think I get it.
 
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1. What is an insulator?

An insulator is a type of material that does not allow electricity or heat to easily pass through it. This means that it can protect objects or people from electric shock or heat transfer.

2. How do insulators work?

Insulators work by having a very high resistance to the flow of electricity or heat. This is due to the way their atoms are arranged, which does not allow for the easy movement of electrons or heat energy.

3. What are some common examples of insulators?

Some common examples of insulators include rubber, plastic, glass, wood, and air. These materials are often used in electrical wiring, building insulation, and protective coatings for electronics.

4. How are insulators different from conductors?

Insulators are different from conductors in that they have high resistance to the flow of electricity or heat, while conductors have low resistance. This means that conductors allow electricity or heat to easily pass through them, while insulators do not.

5. Can insulators become conductors?

In some cases, insulators can become conductors if they are exposed to extreme conditions such as high temperatures or high voltages. This can cause them to break down and allow for the flow of electricity or heat. However, under normal conditions, insulators will maintain their high resistance and not become conductors.

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