In doing a research for crystal and nanoparticles, the XRD data was usually recorded for confirm the diffractogram, and also single crystal XRD also can be applied to get a better imaging of crystal structure. However, the single crystal XRD was need high cost to analysis which lack of the instrument compare to powder crystal structure.
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The data that gave by the powder XRD was a diffractogram which plotted the intensity (y-axis) for the diffraction angel (x-axis). This data usually use for further calculation the crystal lattice parameter. Crystallite size was a data that usually generated from the diffractogram, where usually refer to the particles size. However, this meaning is can be gave a misconception since the interpreter not known different of crystallite size, grain size and crystal size.
Crystallite size was a term that use for the smaller size that can measured from a crystal. The crystallite size is contain of several unit cell of a lattice, which is can be thousand much smaller than the grain size. However, usually the crystallite size have a relationship with the grain size, eventhough it not necessarily. Each crystallite can be arrange regular and irreguler, which can be affected to the diffractogram. Shifted of the peak in the diffractogram compare to the standar usually mean of this arrange.
The grain size was big larger of the crytallite size, where a group of crystallite to form the grain. The grain size usually separated in nanoparticle which gave a colloidal solution since it dispersed in a solution as like water. If the grain was not aggregated, we also called as the particle size. However, much of crystal that synthesized trough heating process can induce an agglomeration and coallecence by the heat, hence produce a crystal that have size much larger than the grain
The grain size usually can be obtained by using Transmittion Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The image that produce by these process was analyzed though several software to give exact measure of the gran/crystal size. Particle Size Analyzer (PSA) also can be use for this purpose, however this method measured the size of the particle by the light scattered process, hence will gave the particle size data, not the grain size.