Dear Manik Bhowmik ,

you know that Mo crystallizes in a cubic lattice; more precisely: in a body centered cubic lattice (BCC).

The interplanar spacings dhkl for the cubic lattice are calculated via:

dhkl = a*(h2 + k2 + l2)-1/2.

The lattice constant for Mo is a = 3,15A = 0,315nm .

You may calculate the hypothetical peak positions of (100) & (111) via the Bragg-Law.

But unfortunately you will have no strong peak for the (100) and the (111) reflections.

Here the selection rules*) for the BCC lattice lead to a structure factor F being equal to zero (Fhkl = 0 for k+k+l=odd). Thus (100) and the (111) reflections are 'forbidden' reflections...

*)

http://groups.mrl.uiuc.edu/chiang/czoschke/diffraction-selection-rules.html

more advanced:

https://weavergroup.ua.edu/uploads/4/8/9/0/48901279/18_-_the_structure_factor_and_selection_rules.pdf

Scroll a bit down in:

https://en.wikipedia.org/wiki/Structure_factor

Best regards

G.M.

Dera Manik Bhowmik ,

additional remark;

in the answer of w.s.l. Boyer of your recent question*) about JCPDS card of Mo, you see, that there is no reflection (100) and (111) listed. This is according to the BCC selection rules as mentioned above...

*) https://www.researchgate.net/post/Can_anyone_please_provide_me_JCPDS_file_for_Mo_JCPDS_01-1208

Thanks for the reference, Gerhard.

re "But unfortunately you will have no strong peak for the (100) and the (111) reflections."

I think it is not unfortunate, since that tells us the structure is BCC. Maybe unfortunate that it is BCC, but that's just what it is. Maybe unfortunate for the questioner and sometimes we'd like to have more peaks visible.

[I'm not really complaining about your answer, just want to point out that the set of hkl with zero intensity tells us useful information. ;)]