- #1
madhusoodan
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Why almost every crystal system has peak around 32 degree (2 theta) ?
XRD peak position near 32 degree
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The discussion centers on the claim that many crystal systems exhibit an XRD peak around 32 degrees (2 theta). Participants question the validity of this assertion, noting that the peak position can vary significantly based on the X-ray wavelength used. They argue that the statement lacks empirical support and is overly broad, as not all crystalline materials show this peak. The conversation highlights the importance of specific experimental data in making such claims about crystal structures. Overall, the consensus is that the assertion is ambiguous and requires further clarification and evidence.
- #2
nasu
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There are tens of thousand(s) (at least) known crystalline materials. How many of these have you checked to make the claim that "almost every crystal"?
Of course, if you make the "around" wide enough it will true for any angle.
Besides, the angle depends on the wavelength of the x-rays. Change your x-ray tube and the angles will change. So the 32 degree value cannot have any special meaning.
Of course, if you make the "around" wide enough it will true for any angle.
Besides, the angle depends on the wavelength of the x-rays. Change your x-ray tube and the angles will change. So the 32 degree value cannot have any special meaning.
- #3
- 32,814
- 4,726
madhusoodan said:
I agree with nasu. This is an ambiguous, and frankly, meaningless claim.
I did an XRD a couple of months ago on MgO. It looks almost like this:
See any 32-degree peak anywhere?
Zz.
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- #4
nasu
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@madhusoodan
I think it will be interesting to see how did you come to this impression. What systems did you study by XRD?
Maybe they all have very similar structures.
I think it will be interesting to see how did you come to this impression. What systems did you study by XRD?
Maybe they all have very similar structures.
- #5
madhusoodan
- 14
- 0
@nasu
However, all ten thousand (s) of crystalline materials fall into 230 space groups only. out of that, many systems have peaks near 32 degrees. Very less number of systems have peak in the range of 20-30.
I should not have used 'almost every'.
However, all ten thousand (s) of crystalline materials fall into 230 space groups only. out of that, many systems have peaks near 32 degrees. Very less number of systems have peak in the range of 20-30.
I should not have used 'almost every'.
- #6
nasu
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Would you care to explain how you got this idea with the 32 degree angle? Otherwise there is no base for discussion.
It's based on your own XRD measurements on some systems?
The mention of 230 space group is not relevant. They can be all cubic crystals and still have all different peaks.
It's based on your own XRD measurements on some systems?
The mention of 230 space group is not relevant. They can be all cubic crystals and still have all different peaks.
- #7
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.. or, as nasu has stated earlier, you can use the identical crystal and just change the x-ray wavelength, and the peak position changes!
@madhusoodan, have you actually performed this XRD experiment yourself?
Zz.
@madhusoodan, have you actually performed this XRD experiment yourself?
Zz.