I have done Rietveld refinement of my sample. Its showing the coexistence of two phases at the same time in the nanoparticles. Is it possible to have more than one symmetry elements at the same time. Please help me out?
Nanoparticles of very small sizes, as a rule, are strongly deformed and can be both in the amorphous phase and in metastable phases, in addition to the main stable phase. For example, silica nanoparticles of the smallest sizes are in an amorphous phase; with an increase in size, metastable phases of cristobalite and tridymite appear, in addition to the quartz phase. And the largest particles are already found only in the quartz phase.
https://www.nature.com/articles/s42004-018-0049-4
Dear Dr. Mikhail Zimin
Thanks for your response.
But, do I need to perform any other characterisation to support my findings?
Sakshi Thakur
Confirmation of the results by several methods is always welcome for greater persuasiveness. For silica and many minerals, FTIR and Raman spectroscopy is informative.
Sakshi Thakur
and the best way would be direct observation using scanning electron microscopy
Dear Sakshi Thakur.
In this particular case we are talking about polymorphs, they have the same molecular formula and different structural arrangements, which is sometimes reflected in different space groups. You should look up references to see the synthesis conditions for both materials and if they have ever been reported together as reaction products.
In principle, with the Rietveld refinement it is more than enough to demonstrate the presence of both phases. You could report the Rietveld fit with a table where you summarize the most important results like cell parameters, space group, discrepancy and composition factors, with their respective standard deviation. What program did you use for refinement? It's good that you used Fullprof, GSASII, Maud or Topas.
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction