Does the bond between atoms affect Thermal Expansion?

In summary, the cobalt-based perovskite cathode has better ionic and electrical conduction but a higher thermal expansion coefficient (TEC) compared to the maganite-based perovskite cathode due to the weaker Co-O bond. This is evident in the TEC values of La0.3Sr0.7CoO3-x (20x10-6K-1) and La0.65Sr0.3MnO3-x (10x10-6K-1). The difference in the La to Sr ratio may not be a good comparison as it affects the size of the gap in the unit cell and the mobility of oxygen ions. Additionally, the size difference between Mn and Co
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Homework Statement


From a journal I read that the cobalt-based perovskite cathode usually has better ionic and electrical conduction but higher TEC compare to Maganite-based perovskite cathode. Because of the Co-O bond is weaker than Mn-O bond.

e.g.
Cobalt-based perovskite cathode, La0.3Sr0.7CoO3-x has thermal expansion coefficient(TEC) at around 20x10-6K-1 while La0.65Sr0.3MnO3-x with TEC around 10 x10-6K-1
...probably this is not a very good comparison because the La to Sr ratio is a little bit different...

The Attempt at a Solution


Is it because of the weaker bond of Co-O bond, the mobility of Oxygen ion increase thus better ionic conduction; And the Co-O make further distance because of weaker bonding force when heat is apply causing high TEC value.

...extra question...sorry can't change the thread tittle...
And i did read somewhere before about the peroskite structure, ABO3, where A is the larger atoms at 8 corner of the unit cell and B is the smaller cation at the center of the unit cell, and if A is much larger than B in radius, the gap in the unit cell is bigger so the oxygen ion can move through the gap easier. I found that Mn and Co is in same row in period table, just Co has 2 extra electron and proton compare to Mn so its size is smaller...probably not much smaller, but does this size difference affect the mobility of oxygen ion too?
 
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I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?
 

FAQ: Does the bond between atoms affect Thermal Expansion?

1. How does the bond between atoms affect thermal expansion?

The bond between atoms can affect thermal expansion in two ways. First, the strength of the bond can determine how much the atoms can move and vibrate, which in turn affects the expansion of the material. Second, the type of bond (e.g. covalent, metallic, or ionic) can determine the direction and magnitude of thermal expansion.

2. Does the bond length or bond angle affect thermal expansion?

Yes, the bond length and bond angle can affect thermal expansion. In general, longer bonds and larger bond angles allow for greater movement and vibration of atoms, leading to a larger thermal expansion. However, this relationship can vary depending on the type of bond and the material's crystal structure.

3. Can thermal expansion change the bond length or bond angle?

Yes, thermal expansion can change the bond length and bond angle. As a material is heated, the atoms gain energy and vibrate more, causing the bond length to increase and the bond angle to change. This can also result in a change in the material's physical properties, such as its density and shape.

4. Is thermal expansion the same for all types of bonds?

No, thermal expansion can vary depending on the type of bond. For example, materials with covalent bonds tend to have a lower thermal expansion compared to materials with metallic bonds. This is because covalent bonds are stronger and more rigid, leading to less movement and vibration of atoms.

5. Can the bond between atoms prevent thermal expansion?

While the bond between atoms can influence thermal expansion, it cannot completely prevent it. All materials will experience some degree of thermal expansion when heated. However, the strength and type of bond can affect the magnitude and direction of thermal expansion in a material.

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