Crystallographic phase inquisition and pattern profiling of sodium chloride nanocrystals: TEM analysis insights

The structural geometry of the predominant sodium chloride (NaCl) phase was examined by powder X-ray diffraction (XRD), followed by whole powder pattern fitting (WPPF) to evaluate the crystallographic profile. The prominent crystalline phase exhibited cubic symmetry, with lattice constants a​=​b=c​= 5.6231 Å and angles α=β​​=​γ​= 90°. The prominent reflection at 2θ​​= 32.08° was indexed to the (200) crystallographic plane. The whole powder pattern fitting (WPPF) method identified halite as the predominant crystalline phase, with a modeled crystalline phase fraction of 100.0 % assigned to NaCl. Multiple established methods were applied to assess and evaluate the average crystallite size, with estimated values ranging from 101.21 to 290.29 nm depending on the adopted diffraction peak-broadening model. The crystallographic analysis revealed a dislocation density of 9.76 × 10⁻5 nm − 2 , crystallinity index of 1.112 with a percentage of crystallinity of 86.03 %, an atomic packing factor of 65.88 %, a lattice volume of 177.797 Å 3 , a unit cell density of 2.183 g/cm 3 and a specific surface area of 27.16 m 2 /g. Microscopic imaging revealed predominantly cubic and faceted particles with well-defined boundaries. The TEM revealed predominantly cubic and faceted particles with well-defined boundaries, while SAED patterns were consistent with highly crystalline halite. The EDS showed Na and Cl contents of 47.83 and 52.17 at %, respectively, indicating a NaCl dominated elemental composition. Overall, the results demonstrate a predominantly halite-type cubic structure and faceted morphology, while the relatively high WPPF residuals warrant cautious interpretation of the refined structural and microstructural parameters.