it seems there's some confusion here: it is clear that the reviewer and some of those commenting are not expert in X-ray diffraction. I don't know if it is more crazy the request of the reviewers or the advises from non experts. The structure of a material is the three dimensional arrangement of the atoms in the unit cell, so the expression "structure size" is meaningless. If the request was some nonsense, and you need somebody stating this, please let me know: I have no problem in sending a letter to the Editor commenting on this.

For a single-phase "well behaving" semiconductor as a result of an XRD analysis I would expect to see a reference to the paper or database containing the structure information (space groups, cell parameter, atomic positions and thermal factors), the actual cell parameters (if refined) that can in principle tell me if there is some macrostrain and then some information about the nanostructure to relate e.g. with the bandgap. Scherrer formula and Williamson-Hall plot give QUALITATIVE information about the nanostructure. The "average crystallite size" is NOT the mean size of the crystallites. The mean is the first moment of the size distribution and neither Scherrer equation nor Williamson-Hall method give you that. It can be easily demonstrated mathematically. We are in 2019.. Scherrer equation is 100+ years old, the WIlliamson and Hall method was developed in the fifties... we are not using tables, mainframes and punch cards, so maybe it's time to check the recent literature and revise your know-how about diffraction? There are nowadays more modern methods to obtain crystallite size distribution information from the pattern.

To comment on Poonam's suggestion, the "average particle size" cannot be obtained with diffraction unless you assume that the particles and the crystallites (that should be called coherently scattering domains)are the same. Without checking where you come from I can guess it's from India as this is where the term "Debye-Scherrer" equation is used. I am still trying to find who is the one that INVENTED this... The formula was proposed by Scherrer alone. No Debye. There is not such a thing called "Debye-Scherrer equation". There is a "Debye Scherrer geometry" but that's it. So if you know where this term comes from, please contact me, as I have tried for a couple months to track it down in order to make a comment about this in the new International Tables for Crystallography vol. H. It is specific of India so somebody has started to use it wrongly and everybody else is following, clearly not knowing what this all about, and not knowing what Scherrer paper contains and what are the limitations in the use of that formula.

hello , you can read my following manuscripts

try Scherrer equation or another method- Williamson-Hall

Via Scherrer equation and Williamsen-Hall method you get estimates of the mean crystallite size.

For crystallite size please see the following link:

http://www.x-raywizards.com/Services/Crystallite_Size/crystallite_size.html

For more details on crystallize size estimation please see:

prism.mit.edu/xray/CrystalSizeAnalysis.ppt

The simple is Scherrer equation

Thank you all for their responses. But I would like to ask about Structure size? What is mean by structure size how to calculate it? I got question about structure size for my manuscript from reviewer. I already know about crystallite size or grain size using scherrer's formula and W-H plot. Thank you....

Following

structure size of metal oxide is a dimensional size (i.e.; a, b, c). You can find structural size, first find average crystallite size using scherrer's formula and miller indices hkl then calculate structural size a,b,c, .

Gashaw Beyene Thank you for the response. How average crystallite size can be used in calculating structural size? Can you please send me exact formula and reference?

most metal oxides have hexagonal structure. so, their dimensional size calculated as

a=3^(-0.5) (λ/sinθ)

b=c=3^0.5 (a)

and spacing (dhkl) of atoms in the given structure is

dhkl = ac/2 (3/(c^2 (h^2+hk+k^2)+3/4(al)^2))^(0.5)

Gashaw Beyene : I believe a, b & c are mostly referred to as lattice parameters. In case it is mentioned as structural size in any manuscript, would you be kind enough to post the reference?

The average particle size can be calculated by using Debye-Scherrer‟s equation.

Please find the attached one chapter based on "SYNTHESIS AND CHARACTERIZATION OF MODIFIED METAL OXIDES AND METAL SULPHIDES NANOPARTICLES"

it seems there's some confusion here: it is clear that the reviewer and some of those commenting are not expert in X-ray diffraction. I don't know if it is more crazy the request of the reviewers or the advises from non experts. The structure of a material is the three dimensional arrangement of the atoms in the unit cell, so the expression "structure size" is meaningless. If the request was some nonsense, and you need somebody stating this, please let me know: I have no problem in sending a letter to the Editor commenting on this.

For a single-phase "well behaving" semiconductor as a result of an XRD analysis I would expect to see a reference to the paper or database containing the structure information (space groups, cell parameter, atomic positions and thermal factors), the actual cell parameters (if refined) that can in principle tell me if there is some macrostrain and then some information about the nanostructure to relate e.g. with the bandgap. Scherrer formula and Williamson-Hall plot give QUALITATIVE information about the nanostructure. The "average crystallite size" is NOT the mean size of the crystallites. The mean is the first moment of the size distribution and neither Scherrer equation nor Williamson-Hall method give you that. It can be easily demonstrated mathematically. We are in 2019.. Scherrer equation is 100+ years old, the WIlliamson and Hall method was developed in the fifties... we are not using tables, mainframes and punch cards, so maybe it's time to check the recent literature and revise your know-how about diffraction? There are nowadays more modern methods to obtain crystallite size distribution information from the pattern.

To comment on Poonam's suggestion, the "average particle size" cannot be obtained with diffraction unless you assume that the particles and the crystallites (that should be called coherently scattering domains)are the same. Without checking where you come from I can guess it's from India as this is where the term "Debye-Scherrer" equation is used. I am still trying to find who is the one that INVENTED this... The formula was proposed by Scherrer alone. No Debye. There is not such a thing called "Debye-Scherrer equation". There is a "Debye Scherrer geometry" but that's it. So if you know where this term comes from, please contact me, as I have tried for a couple months to track it down in order to make a comment about this in the new International Tables for Crystallography vol. H. It is specific of India so somebody has started to use it wrongly and everybody else is following, clearly not knowing what this all about, and not knowing what Scherrer paper contains and what are the limitations in the use of that formula.

Matteo Leoni Sir.. This i s one of the best comments I have read on RG... Highly recommended....

Matteo Leoni Thank you for your kind information as well as concern. Thank you all others for their time and responses too.

Matteo Leoni I have seen such erroneous referring in publications at high impact journals by non-Indian authors:

DOI: 10.1021/am507639b

DOI: 10.1021/am100618h

Dear Sajjad Nasiri, thanks a lot for the references. I'm adding it to my list. Yes there are some non-Indian and there is a lot of high impact publications where the xrd part is complete nonsense. We need to keep teaching and learning and we would need a smarter publication scheme where the referee are always disclosed in the final version of the paper and there is the option to comment

Well, the Scherrer's paper in (Nachr. Ges. Wiss. Gottingen) has a note saying that it was presented by Peter Debye at the meeting on July 26th, 1918. Maybe this adds to the confusion about Scherrer equation. It is interesting that Russian Wiki page about the equation has an explicit mention about it, and states that the term "Debye-Scherrer equation" is sometimes used and that it is wrong. Even though in Russian X-ray science the Scherrer equation is often called Selyakov or Selyakov-Scherrer equation, owing to works of Nikolay Selyakov, e.g., Z. Phys. (1925), 31, 439-444.

This discussion is a bit running off the primary question. But nevertheless for those, who are interested in for the relationship between Peter Debye and Paul Scherrer please have a look at an article by U. Holzwarth and N. Gibson:

Article The Scherrer equation versus the 'Debye-Scherrer equation'

Full text is available at the following link:

https://www.researchgate.net/profile/Mohsen_Mehrabi2/post/What_is_the_difference_between_Scherrer_and_Williamson-Hall_equation/attachment/59d656d579197b80779ad6f5/AS%3A531863217205248%401503817480498/download/holzwarth2011.pdf

By Shearer equation

Thank you

A given the latest comments... at this point let's call it Sharer or Shredder if you just want to add some more nonsense... It seems not everybody actually care to read the other answers and consider what's writing...

Dear Umesh Nakate

You can follow this article; http://repository.um.edu.my/88950/1/solidstatescience2011.pdf

which will help you certainly.

Best of luck .