Maybe it is hard. Normal and standard way is calculated by Ramen. XRD is not related to layer numbers directly.

Dear Maria Magro ,

in principle you can do that.

But pay attention what numbers you have to use.

From Scherrer equation you will get an estimate of the mean z-component (thickness) of the crystallites.

From the peak positions you will get the crystallographic d-spacings.

For 001 and 002 reflections these spacings are in c-direction (z-direction); but they belong to different diffraction orders.

For the c-axis one has c = d001 = 2*d002 = 3*d003 = ...

For graphite the 002 peak ( ~26° in 2 theta) will give around d002 ~ 0,34nm.

So one has c ~ 0,68nm. However the unit cell of graphite exhibits two hexagonal layers of carbon atoms, which are laterally displaced in a and b direction. So the distance DC of the C-atom layers is DC = c/2. Coincidentally we have d002 = c/2. Thus here for the case of 002 peak you can directly take the d spacing from the Bragg law and use it as the spacing of the carbon layers: DC = d002

For the 001 peak ( e.g. of graphene or graphene oxide) you will have d001= c.

But, also here, due to the layered structure of the unit cells, we have also the distance DC of the carbon layers being DC = c/2. Thus in this case the layer distance DC is DC = c/2 = 1/2 *d001.

For the distances of graphene oxide please see the abstract of:

https://www.sciencedirect.com/science/article/abs/pii/S0925963519304388#preview-section-snippets

"The lattice structure of the material was hexagonal with unit cell a = 2.455 Å and c = 8.64 Å and with layer-layer distance of 4.32 Å"

So for estimating the numbers N of layers please take the result W of the Scherrer equation and divide it by the appropriate DC and add a 1 *):

N ~ W/DC + 1

*) please note that the number of planes and the number of plane distances has a difference of 1.

Good luck

and best regards

G.M.

I suspect the 002 is usually used because standards with zero sample broadening having peaks in that angle neighborhood are more readily available. Some diffractometers will also have minimal instrumental peak widths in 20 - 30 degree range and exhibit broader peaks at lower angles. You want to work with peaks where your instrument has best resolution.