Hi everyone. I am studying the precipitate output at 4 pH levels, and got the stacked diffractometers in attachment. My question is, can I say from the image higher counts for the same peak positions, that precipitates obtained at pH 8.5 and 9.0 have higher crystallinity than the other two pH levels. or can I say at least that these precipitates are at least higher organized than the others?
Or Do I need something else to say that?
The term crystallinity needs to be precisely defined.
If we define the crystallinity as expression of perfect crystals and bigger than a certain size then it is described by the peak width which obviously does not change that much.
What changes in your diffractograms are the intensity of reflexes only and these are related to a) the crystal structure and b) the texture or preferred orientations. I would not expect such dramatic changes during ordering...and bigger changes also would affect the peak positions considerably which should have higher impact with increasing 2theta (what I do not see). Therefore, I would expect a drastic variation in texture caused by a different growth speed as function of the pH level. In other words, I would recommend to collect a few images in scanning electron microscope in order to check the shape of your crystals. Maybe, one pH level prefers the growth of needles whereas the other grows plates...
You may follow this article:
https://www.researchgate.net/publication/325497664_Crystallinity_mediated_variation_in_optical_and_electrical_properties_of_hydrothermally_synthesized_boehmite_g-AlOOH_nanoparticles?_sg=Tv2njk1d20sn4uNKnvz9ZxWJrX898tbys-6arx4tOdkQ7CMe_J4SZVgztAXtquPTeCqE35m237XsQ1WSl7UlE1FQ2KWOe2GfMuk4_SHv.TLFxRs06WnrW_BL6A1tqCTQ3PMerhWAIpJEqFtNQxR59jkM0Su7ea1nz-5-w1psqXkT57Si0BW5uWADpcuENNQ
Some basic understandings about XRD spectra are as follows and may be helpful:
# Peak positions are related to unit cell sizes.
# Peak intensities are related to atom species (composition) and positions of atoms.
# Peak width is related to size of crystals.
From some free software as an example UnitCell, lattice values could be estimated, from comparison with ICDD's Powder Diffration File you can figure out the structure.
The other useful analysis is related to grain size estimated by Deybe Scherrer equation,. Although grain size could be estimated, XRD analysis is not suitable to infere precipitates crystallinity
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction
- XRD Analysis