centrosymmetric space group
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Author(s):  
Július Sivý ◽  
Dušan Bortňák ◽  
Daniel Végh ◽  
Erik Rakovský

The crystals, C11H4BrF5N2S, (I), 1-((4-bromothiophen-2-yl)methylene)-2-(perfluorophenyl)hydrazine and C12H6BrF5N2S, (II), 1-((4-bromo-5-methylthiophen-2-yl)methylene)-2-(perfluorophenyl)hydrazine are molecules with two rings and hydrazone part like a centre of the molecule. The compounds have been synthesized and characterized by elemental, spectroscopic (1H-NMR) analysis. The crystal structures of the solid phase were determined by single crystal X-ray diffraction method. They crystallize in the monoclinic space group with Z = 4 and Z = 2 molecules per unit-cell. The compound (I) crystallizes as a racemate in the centrosymmetric space group and the compound (II) crystallizes as a non-racemate in the non-centrosymmetric space group. The “absolute configuration and conformation for bond values” were derived from the anomalous dispersion (ad) for (II). The crystal structures are revealed diverse non-covalent interactions such as intra- and interhydrogen bonding, π-ring···π-ring, C-H···π-ring and they were investigated. The expected stereochemistry of hydrazones atoms C7, N2 and N1 were confirmed for (I) and (II). The hole molecule of the (I), and (II) possesses “a boat conformation” like a 6-membered ring. The results of the single crystal studies are reproduced with the help of Hirshfeld surface study and Gaussian software.


IUCrData ◽  
2021 ◽  
Vol 6 (9) ◽  
Author(s):  
Qifa Hu ◽  
Bin Wen ◽  
Changzeng Fan

An aluminium-abundant Al8Mn5/γ-brass-type intermetallic with formula Al8.6Mn4.4, which is isotypic with γ-Al8Cr5 and γ-Al8V5, was discovered by high-temperature sintering of an Al/Mn mixture with initial composition Al2Mn. Structure analysis revealed that one special position (Wyckoff site 18h in space group R\overline{3}m) is shared by Al and Mn, with refined site occupancy factors of 0.7 and 0.3, respectively. The present low-temperature Al8Mn5-type phase crystallizes in the centrosymmetric space group R\overline{3}m (No. 166), rather than R3m (No. 160) as previously reported for the same intermetallic characterized by TEM measurements [Zeng et al. (2018). Acta Mater. 153, 364–376].


2021 ◽  
Vol 54 (4) ◽  
Author(s):  
Neeraj K. Rajak ◽  
Arya Mohan ◽  
Deepshikha Jaiswal-Nagar

The Rietveld refinement technique has been used to determine the extent of intergrowth of the Bi2Sr2CuO6+x phase and co-crystallization of competing phases in the high-temperature superconductor Bi2Sr2CaCu2O8+x (Bi-2212). The refinement was done on powder diffractograms obtained on powders made by grinding single crystals of Bi2Sr2CaCu2O8+x grown using two different self-flux techniques, namely the pressure technique and the regrowth technique, and ground for either 2 min or 2 h. The Rietveld programs JANA and FULLPROF were used for the refinement and both gave consistent results. The Bi and Sr atom positions were refined in the average structure of centrosymmetric space group Bbmb. To incorporate Bi-atom modulation and extract information about the modulation vector, refinement was done in the centrosymmetric space group N^{Bbmb}_{1\overline 11}(Bbmb(0γ1)). The b* component of the modulation vector decreases with a decrease in the superconducting transition temperature in the pressure-technique sample compared with the regrowth sample, suggesting a better alignment of the CuO2 planes with respect to the Bi–O planes in the pressure-technique sample. All the samples exhibit a strong preferred orientation effect. Values of the March–Dollase parameters corresponding to the preferred orientation function were obtained. Brindley absorption contrast factors t ϕ were also calculated, together with the effect of microabsorption on the number of phases present in each sample. Rietveld refinements incorporating all the factors resulted in excellent values for the goodness-of-fit parameters for all the samples, with the lowest value of 2.08 for the pressure-technique sample ground for 2 min. Additionally, the powders corresponding to the pressure-technique crystals have no co-crystallizing phase and ∼94% of the Bi-2212 phase, suggesting that crystals grown by the pressure technique are of extremely good quality, much better than those grown by the regrowth flux technique.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 379
Author(s):  
Majid Ismail Tamboli ◽  
Yushi Okamoto ◽  
Yohei Utsumi ◽  
Takayuki Furuishi ◽  
Siran Wang ◽  
...  

Disopyramide (DPA) is as a class IA antiarrhythmic drug and its crystallization from cyclohexane at ambient condition yields lower melting form crystals which belong to the monoclinic centrosymmetric space group P21/n, having two molecules in an asymmetric unit. Crystal structure analysis of pure DPA revealed closely associated DPA molecules aggregates via amide–amide dimer synthon through the N–H∙∙∙O hydrogen bond whereas the second amide hydrogen N–H engaged in an intramolecular N–H∙∙∙N hydrogen bond with N-nitrogen of 2-pyridine moieties. Crystallization of DPA and phthalic acid (PA) in 1: 1 stoichiometric molar ratio from acetone at ambient condition yielded block shape crystals of 1:1 DPA_PA salt. Its X-ray single crystal structure revealed the formation of salt by transfer of acidic proton from one of the carboxylic acidic groups of PA to the tertiary amino group of chain moiety (N3-nitrogen atom) of DPA molecules. DPA_PA salt crystals belong to the monoclinic centrosymmetric space group P21/n, comprising one protonated DPA and one PA¯ anion (hydrogen phthalate counterion) in an asymmetric unit and linked by N–H∙∙∙O and C–H∙∙∙O hydrogen bonds. Pure DPA and DPA_PA salt were further characterized by differential calorimetric analysis, thermal gravimetric analysis, powder x-ray diffraction and infrared spectroscopy.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1804
Author(s):  
Liliana Dobrzańska

The crystal structures of a series of Ag(I) complexes with 1,3-bis(imidazol-1-ylmethyl)-5-methylbenzene (L) and the counterions BF4− (1), PF6− (2), ClO4− (3), and CF3SO3− (4) were analysed to determine the effect of the latter on their formation. All resulting compounds crystallise in the non-centrosymmetric space group Cc of a monoclinic system and show the formation of cationic, polymeric 1D Ag(I) complexes. SCXRD analyses revealed that compounds 1–3 are isostructural, though 1 shows opposite handedness compared to 2 and 3, resulting in an inversed packing arrangement. The presence of the larger, elongated triflate counterion in 4 leads to a different ligand conformation, as well as different arrangements of the ligand in the cationic chain, and simultaneously results in a packing that exhibits fewer similarities with the remaining three compounds.


Author(s):  
Dhananjay Dey ◽  
I. Shruti ◽  
Deepak Chopra ◽  
T. P. Mohan

The compound N-[2-(4-fluoro-3-phenoxybenzoyl)hydrazinecarbothioyl]benzamide, C21H16FN3O3S, crystallizes in the monoclinic centrosymmetric space group P21/c and its molecular conformation is stabilized via an intramolecular N—H...O hydrogen bond. The corresponding para-methoxy derivative, namely, N-[2-(4-fluoro-3-phenoxybenzoyl)hydrazinecarbothioyl]-4-methoxybenzamide, C22H18FN3O4S, crystallizes in the monoclinic centrosymmetric space group C2/c. The supramolecular network mainly comprises N—H...O, N—H...S and C—H...O hydrogen bonds, which contribute towards the formation of the crystal structures for the two molecules. The different intermolecular interactions have been further analysed using Hirshfeld surface analysis and fingerprint plots.


Author(s):  
Ezhumalai David ◽  
Krishnan Thirumoorthy ◽  
Nallasamy Palanisami

A series of new donor-acceptor (D–A) type N-arylated ferrocenyl pyrazole chromophores 1-4 have been synthesized and spectroscopically characterized. The molecules 2-4 crystalizes in centrosymmetric space group, but shows weak second...


2021 ◽  
Author(s):  
Huanhuan Cheng ◽  
Abudukadi Tudi ◽  
Peng Wang ◽  
Kewang Zhang ◽  
Zhihua Yang ◽  
...  

A new ternary Ba-based selenide, Ba3SiSe5, was synthesized by high-temperature solid-state method. It crystalizes in the centrosymmetric space group Pnma (No. 62) of the orthorhombic system. The structure of the...


2021 ◽  
Author(s):  
Hongbo Gao ◽  
Ruijiao Chen ◽  
kewang zhang ◽  
Ailijiang Abudurusuli ◽  
Kangrong Lai ◽  
...  

A new fluorine-contained chalcohalide, Ba4GaS4F3, has been synthesized by conventional high-temperature solid-state reaction. The compound crystallizes in the centrosymmetric space group I41/a with a = b = 16.628 (5) Å,...


2021 ◽  
Author(s):  
Zhongxu Fan ◽  
Chen Bai ◽  
Hongsheng Shi ◽  
Min Zhang ◽  
Bei Zhang ◽  
...  

A new heavy metal oxychloride, RbPb8O4Cl9, has been synthesized by high-temperature solution method. The compound crystallizes in the centrosymmetric space group P4/n (no. 85) and exhibits a three-dimensional (3D) framework...


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