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Journal of Applied Crystallography Jun 2023W-type hexaferrites with varied Co/Zn ratios were synthesized and the magnetic order was investigated using neutron powder diffraction. In SrCoFeO and SrCoZnFeO a planar...
W-type hexaferrites with varied Co/Zn ratios were synthesized and the magnetic order was investigated using neutron powder diffraction. In SrCoFeO and SrCoZnFeO a planar ('') magnetic ordering was found, rather than the uniaxial ordering (6/'') found in SrZnFeO which is common in most W-type hexaferrites. In all three studied samples, non-collinear terms were present in the magnetic ordering. One of the non-collinear terms is common to the planar ordering in SrCoZnFeO and uniaxial ordering in SrZnFeO, which could be a sign of an imminent transition in the magnetic structure. The thermomagnetic measurements revealed magnetic transitions at 520 and 360 K for SrCoFeO and SrCoZnFeO, and Curie temperatures of 780 and 680 K, respectively, while SrZnFeO showed no transition but a Curie temperature at 590 K. This leads to the conclusion that the magnetic transition can be adjusted by fine-tuning the Co/Zn stoichiometry in the sample.
PubMed: 37284272
DOI: 10.1107/S1600576723002133 -
Inorganic Chemistry Oct 2023We report the synthesis, characterization, and photoelectric and electrochemical properties of (CHNH)ZnCoBr ( = 0.0, 0.3, 0.5, 0.7, and 1.0) samples. X-ray powder and...
We report the synthesis, characterization, and photoelectric and electrochemical properties of (CHNH)ZnCoBr ( = 0.0, 0.3, 0.5, 0.7, and 1.0) samples. X-ray powder and single-crystal diffraction confirm the formation of solid solution across the entire range. Additionally, as the cobalt concentration increases, the crystallinity of the samples decreases, as indicated by the powder diffraction patterns. All samples remain stable up to 560 K, beyond which they decompose into CHNHBr and the respective bromide. The semiconductor behavior of the compounds is confirmed through optical absorption measurements, and band gap values are determined by using the Tauc method from diffuse reflectance spectra. Raman spectroscopy reveals a slight redshift in all vibration modes with increasing cobalt content. Finally, photovoltaic measurements on solar cells constructed with (MA)CoBr perovskite exhibit modest performance, and electrochemical measurements indicate that the compound with the composition (MA)ZnCoBr exhibits the highest current for electrochemical water reduction during oxygen evolution.
PubMed: 37814970
DOI: 10.1021/acs.inorgchem.3c02574 -
Journal of Applied Crystallography Aug 2022In materials and earth science, but also in chemistry, pharmaceutics and engineering, the quantification of elements and crystal phases in solid samples is often...
Multivariate versus traditional quantitative phase analysis of X-ray powder diffraction and fluorescence data of mixtures showing preferred orientation and microabsorption.
In materials and earth science, but also in chemistry, pharmaceutics and engineering, the quantification of elements and crystal phases in solid samples is often essential for a full characterization of materials. The most frequently used techniques for this purpose are X-ray fluorescence (XRF) for elemental analysis and X-ray powder diffraction (XRPD) for phase analysis. In both methods, relations between signal and quantity do exist but they are expressed in terms of complex equations including many parameters related to both sample and instruments, and the dependence on the active element or phase amounts to be determined is convoluted among those parameters. Often real-life samples hold relations not suitable for a direct quantification and, therefore, estimations based only on the values of the relative intensities are affected by large errors. Preferred orientation (PO) and microabsorption (MA) in XRPD cannot usually be avoided, and traditional corrections in Rietveld refinement, such as the Brindley MA correction, are not able, in general, to restore the correct phase quantification. In this work, a multivariate approach, where principal component analysis is exploited alone or combined with regression methods, is used on XRPD profiles collected on designed mixtures to face and overcome the typical problems of traditional approaches. Moreover, the partial or no known crystal structure (PONKCS) method was tested on XRPD data, as an example of a hybrid approach between Rietveld and multivariate approaches, to correct for the MA effect. Particular attention is given to the comparison and selection of both method and pre-process, the two key steps for good performance when applying multivariate methods to obtain reliable quantitative estimations from XRPD data, especially when MA and PO are present. A similar approach was tested on XRF data to deal with matrix effects and compared with the more classical fundamental-parameter approach. Finally, useful indications to overcome the difficulties of the general user in managing the parameters for a successful application of multivariate approaches for XRPD and XRF data analysis are given.
PubMed: 35974739
DOI: 10.1107/S1600576722004708 -
IUCrJ Mar 2023The transformation processes of non-solvated ibrutinib into a series of halogenated benzene solvates are explored in detail here. The transformation was studied in real...
The transformation processes of non-solvated ibrutinib into a series of halogenated benzene solvates are explored in detail here. The transformation was studied in real time by X-ray powder diffraction in a glass capillary. Crystal structures of chlorobenzene, bromobenzene and iodobenzene solvates are isostructural, whereas the structure of fluorobenzene solvate is different. Four different mechanisms for transformation were discovered despite the similarity in the chemical nature of the solvents and crystal structures of the solvates formed. These mechanisms include direct transformations and transformations with either a crystalline or an amorphous intermediate phase. The binding preference of each solvate in the crystal structure of the solvates was examined in competitive slurry experiments and further confirmed by interaction strength calculations. Overall, the presented system and online X-ray powder diffraction measurement provide unique insights into the formation of solvates.
PubMed: 36815712
DOI: 10.1107/S2052252523001197 -
Journal of Pharmaceutical Sciences Jun 2022Members of the IQ Consortium ″Working Group on Characterization on Amorphous Solid Dispersions″ shares here a perspective on the analytical challenges, and... (Review)
Review
Members of the IQ Consortium ″Working Group on Characterization on Amorphous Solid Dispersions″ shares here a perspective on the analytical challenges, and limitations of detecting low levels of crystalline drug substance in amorphous solid dispersions (ASDs) and associated drug products. These companies aim to employ highly sensitive commercially available analytical technologies to guide development, support control strategies, and enable registration of quality products. We hope to promote consistency in development and registration approaches and guide the industry in development of "characterization best practices" in the interest of providing high quality products for patients. The first half of this perspective highlights the unique challenges of analytical methodologies to monitor crystalline drug substance in ASDs and their associated drug products. Challenges around use of limit tests, analyte spiking experiments, and method robustness are also underscored. The latter half describes the merits and limitations of the diverse analytical "toolbox" (such as XRPD, NIR and DSC), which can be readily applied during development and, in some cases, considered for potential application and validation in the commercial QC setting when necessary.
Topics: Calorimetry, Differential Scanning; Chemistry, Pharmaceutical; Crystallization; Humans; Solubility; X-Ray Diffraction
PubMed: 35041831
DOI: 10.1016/j.xphs.2022.01.007 -
Zhongguo Zhong Yao Za Zhi = Zhongguo... Oct 2020The optimal process conditions for preparing icariin nanosuspension(ICA-NS) and lyophilized powder were determined to initially investigate their stability and...
The optimal process conditions for preparing icariin nanosuspension(ICA-NS) and lyophilized powder were determined to initially investigate their stability and characterize the prepared nanosuspension. The anti-solvent precipitation-high shear method was used in the experiment, and the particle size(size), polydispersity index(PDI), and sedimentation ratio(H_0/H) were used as indicators to determine the optimal process conditions of ICA-NS by single-factor test method. Lyophilized powder of nanosuspension was prepared by freeze-drying method, and its crystalline morphology was observed by transmission electron microscope. The equilibrium solubility of icariin, nanosuspension and lyophilized powder was determined by shake flask method and their stability was initially investigated. The crystal structure of nano-lyophilized powder was characterized by differential scanning calorimetry(DSC) and X-ray powder diffraction(XRD). Finally, the dissolution in vitro of nano-lyophilized powder was determined by the small cup method to prepare the ideal icariin nanoparticles. Soy lecithin(SPC) was used as the main stabilizer and povidone was used as the steric stabilizer. The prepared ICA-NS was nearly round in shape, uniform in size, and stable at room temperature. The average particle size was(62.51±7.11) nm. The drug loading was 16% and the solubility was 50 times higher than that of the original drug. Drugs in suspension and lyophilized powder were dispersed in nanoparticles in an amorphous state. The in vitro dissolution experiments showed that the cumulative release rate of nano-lyophilized powder reached 100% at 10 min, indicating that the dissolution rate of lyophilized powder was significantly increased after preparing into nano-lyophilized powder. Preparation of ICA-NS lyophilized powder by antisolvent precipitation-high shear method is simple, easy to operate, and can significantly improve its water solubility. However, the process conditions have some influence on its stability, which needs further study.
Topics: Biological Availability; Flavonoids; Nanoparticles; Particle Size; Powders; Solubility; Suspensions; X-Ray Diffraction
PubMed: 33350263
DOI: 10.19540/j.cnki.cjcmm.20200328.301 -
Molecules (Basel, Switzerland) Nov 2020The objective of the research reported herein is to compare the compaction properties of three different chitin extracts from the organisms most used in the seafood...
The objective of the research reported herein is to compare the compaction properties of three different chitin extracts from the organisms most used in the seafood industry; namely crabs, shrimps and squids. The foregoing is examined in relation to their polymorphic forms as well as compression and compaction behavior. Chitin extracted from crabs and shrimps exhibits the α-polymorphic form whilst chitin extracted from squid pins displays a β-polymorphic form. These polymorphs were characterized using FTIR, X-ray powder diffraction and scanning electron microscopy. Pore diameter and volume differ between the two polymorphic powder forms. The β form is smaller in pore diameter and volume. Scanning electron microscopy of the two polymorphic forms shows clear variation in the arrangement of chitin layers such that the α form appears more condensed due to the anti-parallel arrangement of the polymer chains. True, bulk and tapped densities of these polymorphs and their mixtures indicated poor flowability. Nevertheless, compression and compaction properties obtained by applying Heckle and Kawakita analyses indicated that both polymorphs are able to be compacted with differences in the extent of compaction. Chitin compacts, regardless of their origin, showed a very high crushing strength with very fast dissolution which makes them suitable for use as fast mouth dissolving tablets. Moreover, when different chitin powders are granulated with two model drugs, i.e., metronidazole and spiramycin they yielded high crushing strength and their dissolution profiles were in accordance with compendial requirements. It is concluded that the source of chitin extraction is as important as the polymorphic form when compression and compaction of chitin powders is carried out.
Topics: Chitin; Compressive Strength; Drug Carriers; Drug Compounding; Drug Delivery Systems; Excipients; Materials Testing; Metronidazole; Microscopy, Electron, Scanning; Porosity; Powders; Pressure; Solubility; Spectroscopy, Fourier Transform Infrared; Spiramycin; Tablets; Water; X-Ray Diffraction
PubMed: 33198143
DOI: 10.3390/molecules25225269 -
Inorganic Chemistry Aug 2022Combining different anions in one material allows tuning of its structural, magnetic, and electronic properties. We hereby present the mixed anion compound SrBNH,...
Combining different anions in one material allows tuning of its structural, magnetic, and electronic properties. We hereby present the mixed anion compound SrBNH, expanding the less-known class of nitridoborate hydrides. Solid-state reaction of SrN, BN, and SrH at 850 °C in a tube furnace yielded a gray, air- and moisture-sensitive powder of SrBNH. It crystallizes as colorless platelets in the orthorhombic space group (no. 62) with = 9.9164(2), = 3.9079(1), and = 10.1723(2) Å and = 4. An initial structural model was obtained from single-crystal X-ray diffraction data and corroborated by neutron powder diffraction data of the corresponding deuteride. Further validation by H and B MAS NMR, FTIR, and Raman spectroscopy complements the structural proof of anionic hydrogen present in the compound. Quantum chemical calculations support the experimental findings and reveal the electronic structure of SrBNH.
PubMed: 35917523
DOI: 10.1021/acs.inorgchem.2c01688 -
Journal of Synchrotron Radiation Sep 2023Following Phase 2 of the upgrade of the ESRF in which the storage ring was replaced by a new low-emittance ring along with many other facility upgrades, the status of...
Following Phase 2 of the upgrade of the ESRF in which the storage ring was replaced by a new low-emittance ring along with many other facility upgrades, the status of ID22, the high-resolution powder-diffraction beamline, is described. The beamline has an in-vacuum undulator as source providing X-rays in the range 6-75 keV. ID22's principle characteristics include very high angular resolution as a result of the highly collimated and monochromatic beam, coupled with a 13-channel Si 111 multi-analyser stage between the sample and a Dectris Eiger2 X 2M-W CdTe pixel detector. The detector's axial resolution allows recorded 2θ values to be automatically corrected for the effects of axial divergence, resulting in narrower and more-symmetric peaks compared with the previous fixed-axial-slit arrangement. The axial acceptance can also be increased with increasing diffraction angle, thus simultaneously improving the statistical quality of high-angle data. A complementary Perkin Elmer XRD1611 medical-imaging detector is available for faster, lower-resolution data, often used at photon energies of 60-70 keV for pair-distribution function analysis, although this is also possible in high-resolution mode by scanning up to 120° 2θ at 35 keV. There are various sample environments, allowing sample temperatures from 4 K to 1600°C, a capillary cell for non-corrosive gas atmospheres in the range 0-100 bar, and a sample-changing robot that can accommodate 75 capillary samples compatible with the temperature range 80 K to 950°C.
PubMed: 37462688
DOI: 10.1107/S1600577523004915 -
Acta Crystallographica Section B,... Feb 2022Synthetic and naturally occurring forms of tricopper orthotellurate, CuTeO (the mineral mcalpineite) have been investigated by 3D electron diffraction (3D ED), X-ray...
Synthetic and naturally occurring forms of tricopper orthotellurate, CuTeO (the mineral mcalpineite) have been investigated by 3D electron diffraction (3D ED), X-ray powder diffraction (XRPD), Raman and infrared (IR) spectroscopic measurements. As a result of the diffraction analyses, CuTeO is shown to occur in two polytypes. The higher-symmetric CuTeO-1C polytype is cubic, space group Ia3, with a = 9.537 (1) Å and V = 867.4 (3) Å as reported in previous studies. The 1C polytype is a well characterized structure consisting of alternating layers of CuO octahedra and both CuO and TeO octahedra in a patchwork arrangement. The structure of the lower-symmetric orthorhombic CuTeO-2O polytype was determined for the first time in this study by 3D ED and verified by Rietveld refinement. The 2O polytype crystallizes in space group Pcca, with a = 9.745 (3) Å, b = 9.749 (2) Å, c = 9.771 (2) Å and V = 928.3 (4) Å. High-precision XRPD data were also collected on CuTeO-2O to verify the lower-symmetric structure by performing a Rietveld refinement. The resultant structure is identical to that determined by 3D ED, with unit-cell parameters a = 9.56157 (19) Å, b = 9.55853 (11) Å, c = 9.62891 (15) Å and V = 880.03 (2) Å. The lower symmetry of the 2O polytype is a consequence of a different cation ordering arrangement, which involves the movement of every second CuO and TeO octahedral layer by (1/4, 1/4, 0), leading to an offset of TeO and CuO octahedra in every second layer giving an ABAB* stacking arrangement. Syntheses of CuTeO showed that low-temperature (473 K) hydrothermal conditions generally produce the 2O polytype. XRPD measurements in combination with Raman spectroscopic analysis showed that most natural mcalpineite is the orthorhombic 2O polytype. Both XRPD and Raman spectroscopy measurements may be used to differentiate between the two polytypes of CuTeO. In Raman spectroscopy, CuTeO-1C has a single strong band around 730 cm, whereas CuTeO-2O shows a broad double maximum with bands centred around 692 and 742 cm.
Topics: Electrons; Powder Diffraction; Spectrophotometry, Infrared; Spectrum Analysis, Raman; X-Ray Diffraction
PubMed: 35129117
DOI: 10.1107/S2052520621013032