The Rietveld Refinement in the EXPO Software: A Powerful Tool at the End of the Elaborate Crystal Structure Solution Pathway

Altomare, Angela; Capitelli, Francesco; Corriero, Nicola; Cuocci, Corrado; Falcicchio, Aurelia; Moliterni, Anna; Rizzi, Rosanna

doi:10.3390/cryst8050203

Cited by 11 publications

(6 citation statements)

References 70 publications

(79 reference statements)

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“…By refining the positions and lattice parameters we obtain the fitted curves for ZnS nanostructures given in Figure 2. The refined parameters R p (profile),R wp (weight profile) and R e -(expected) with regular convergence and least square(χ 2 ) gives the exact fitting [18] and these values are given in Table 1.…”

Section: Structural Analysismentioning

confidence: 99%

Photocatalytic Degradation of Malachite Green Dye Using Zinc Sulfide Nanostructures

Thomas¹,

Kadam

et al. 2021

ChemistrySelect

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Zinc Sulfide (ZnS) get important attention as a semiconductor photocatalyst among other transition metal sulfides due to its fascinating and extraordinary properties. Here ZnS nanoparticles are synthesized by hydrothermal method using zinc acetate and sodium sulfide as precursors. The structural properties of ZnS was studied by using X‐Ray Diffraction technique (XRD).Exact fitting and crystal information of the sample was obtained from Rietveld refinement with Crystallographic Open Database (COD). It shows that ZnS follows cubic structure without any impurity peaks. Crystallite size and lattice strain values are calculated by using Williamson‐Hall (W−H) Plot method. As temperature increases, the particle size also going to increases due to atomic diffusion phenomena. Tauc plot indicates that the bandgap values decreases with increasing temperature. Accurate determination of bandgap values was analyzed by Boltzmann fitting using sigmoid function. Chemical states of elements were obtained with X‐ray Photoelectron Spectroscopy (XPS).Surface morphology and elemental analysis of ZnS nanoparticles was determined from Field Emission Scanning Electron Spectroscopy (FESEM) and Energy Dispersive spectroscopy (EDS). Then the photocatalytic dye degradation efficiency of synthesized particles for Malachite Green (MG) dye was evaluated. From the studies it was found that ZnS is an efficient photocatalyst and it can be used as a perfect future material to avoid the water pollution.

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Section: Structural Analysismentioning

confidence: 99%

Photocatalytic Degradation of Malachite Green Dye Using Zinc Sulfide Nanostructures

Thomas¹,

Kadam

et al. 2021

ChemistrySelect

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“…To identify the remaining content of the sample we fitted the CSD structure for pure THL and NIC to our cocrystals. This revealed the remaining amount to be uncrystallized Nicotinamide, however, the amount is minuscule at 1.5% and even less for the samples produced at 1.5 kg/hr at 0.9% [ 58 , 59 ]. From the results of this experiment, it can be concluded that the scale-up process had an insignificant effect on the purity of the cocrystals.…”

Section: Resultsmentioning

confidence: 99%

“…This is likely due to the presence of the NIC coformer, with the more readily soluble NIC, assisting dissolution [ 61 ]. From this, it can be concluded that neither the cocrystallization process nor the scaling-up process had an adverse effect on the solubility of the theophylline [ 59 ].…”

Section: Resultsmentioning

confidence: 99%

Continuous Manufacture and Scale-Up of Theophylline-Nicotinamide Cocrystals

et al. 2021

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The aim of the study was the manufacturing and scale-up of theophylline-nicotinamide (THL-NIC) pharmaceutical cocrystals processed by hot-melt extrusion (HME). The barrel temperature profile, feed rate and screw speed were found to be the critical processing parameters with a residence time of approximately 47 s for the scaled-up batches. Physicochemical characterization using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction of bulk and extruded materials revealed the formation of high purity cocrystals (98.6%). The quality of THL-NIC remained unchanged under accelerated stability conditions.

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“…A force convergence threshold of 1•10 −3 , mixing beta of .4, and automatic k points 1 2 2 0 0 0 were also used for all calculations. The theoretical calculations of UAM-1 were obtained using the fixed cell relaxation procedure starting from the indexed cell obtained by the EXPO14 Rietveld Refinement program suite (Altomare et al, 2018). The structural coordinates of half of the molecular entity were modified from the single-crystal X-ray structure experimentally obtained for Ag 2 BDC through the replacement of half BDC with half NDC ligands.…”

Section: Ft-irmentioning

confidence: 99%

Room-temperature synthesis of nanometric and luminescent silver-MOFs

Celis-Arias

Garduño-Wilchis²,

Alarcón³

et al. 2023

Front. Chem.

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Three silver-MOFs were prepared using an optimized, room-temperature methodology starting from AgNO₃ and dicarboxylate ligands in water/ethanol yielding Ag2BDC, Ag2NDC (UAM-1), and Ag2TDC (UAM-2) at 38%–48% (BDC, benzenedicarboxylate; NDC, 1,8-naphthalene-dicarboxylate; TDC, p-terphenyl-4,4″-dicarboxylate). They were characterized by PXRD/FT-IR/TGA/photoluminescence spectroscopy, and the former two by SEM. These materials started decomposing at 330°C, while showing stability. The crystal structure of UAM-1 was determined by PXRD, DFT calculations, and Rietveld refinement. In general, the structure was 3D, with the largest Ag-O bond interlinking 2D layers. The FT-IR spectra revealed 1450 and 1680 bands (cm−1) of asymmetrically stretching aniso-/iso-bidentate -COO in coordination with 2/3-Ag atoms, accompanied by Ag-O bands at 780–740 cm−1, all demonstrating the network formation. XRD and SEM showed nanometric-scale crystals in Ag₂BDC, and UAM-1 developed micrometric single-stranded/agglomerated fibrillar particles of varying nanometric widths. Luminescence spectroscopy showed emission by Ag₂BDC, which was attributed to ligand-to-metal or ligand-to-metal–metal transitions, suggesting energy transfer due to the short distance between adjacent BDC molecules. UAM-1 and UAM-2 did not show luminescence emission attributable to ligand-to-metal transition; rather, they presented only UV emission. The stabilities of Ag₂BDC and UAM-1 were evaluated in PBS/DMEM/DMEM+FBS media by XRD, which showed that they lost their crystallinity, resulting in AgCl due to soft–soft (Pearson’s principle) affinity.

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The Rietveld Refinement in the EXPO Software: A Powerful Tool at the End of the Elaborate Crystal Structure Solution Pathway

Cited by 11 publications

References 70 publications

Photocatalytic Degradation of Malachite Green Dye Using Zinc Sulfide Nanostructures

Photocatalytic Degradation of Malachite Green Dye Using Zinc Sulfide Nanostructures

Continuous Manufacture and Scale-Up of Theophylline-Nicotinamide Cocrystals

Room-temperature synthesis of nanometric and luminescent silver-MOFs

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