Radius Ratio of Crystal: Interstitial vs Large Atom

In summary, the difference between the radius of the interstitial atom and the large atom in a crystal's radius ratio depends on the specific crystal and its atoms. The concept may be better understood by visual aids, such as pictures or diagrams, as 2-d drawings may not accurately represent the structure.
  • #1
asdf1
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in the radius ratio of a crystal, what is the difference between the radius of the interstitial atom and large atom?
 
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  • #2
Don't you think that depends one heckuva lot on exactly what crystal you are talking about and what the atoms are?

Unless you are asking about the difference in meaning and I would think that would be obvious!
 
  • #3
i guess so, but i saw that in a textbook about crystallography, and I'm not really clear on what's the difference... it'd be nice if that book could show those two things in a picture or diagram...
 
  • #4
The bulk of a crystal is a repeating pattern,
so a "unit cell" can be centered on any atom.
There are many different types of "unit cells",
some retained for the sake of tradition.

Whenever the book describes structure vectors,
assemble a set of sticks in 3-d to show them.
Especially at first, 2-d drawings might not cut it.
 
  • #5
ok, thanks!
 

FAQ: Radius Ratio of Crystal: Interstitial vs Large Atom

What is the radius ratio of crystal?

The radius ratio of a crystal is the ratio of the radius of the interstitial atom to the radius of the large atom in the crystal. It is used to determine the stability and structure of a crystal lattice.

How is the radius ratio calculated?

The radius ratio is calculated by dividing the radius of the interstitial atom by the radius of the large atom. This value is typically between 0.155 and 0.225 for stable crystal structures.

What is the significance of the radius ratio in crystal structures?

The radius ratio is significant because it determines the coordination number and geometry of the crystal lattice. A high radius ratio leads to a higher coordination number and more complex crystal structures, while a low radius ratio results in a lower coordination number and simpler structures.

How does the radius ratio affect interstitial and large atoms in a crystal?

A high radius ratio means that the interstitial atoms can easily fit between the large atoms in the crystal lattice, leading to a larger number of interstitial sites and more complex structures. A low radius ratio means that the interstitial atoms cannot fit as easily, resulting in a lower number of interstitial sites and simpler structures.

Can the radius ratio of a crystal change?

Yes, the radius ratio of a crystal can change if the temperature or pressure changes. This can result in a different crystal structure with a different coordination number and geometry. Additionally, the introduction of impurities or defects in the crystal can also affect the radius ratio and alter the crystal structure.

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