Accurate Crystal Structure Refinement of La3Ta0.25Zr0.50Ga5.25O14

Crystallography Reports - An accurate X-ray diffraction study of a La3Ta0.25Zr0.50Ga5.25O14 single crystal (a = 8.2574(4) Å, c = 5.1465(4) Å, sp. gr. P321, Z = 1, R/R w = 0.62/0.57% for...     

Single Crystal X-ray Diffraction Study of a Pure Natrolite Sample

The crystal structure of a pure natrolite sample, Na₂(Al₂Si₃O₁₀)·2H₂O, coming from Asheken, Ethiopia, has been analysed by single crystal X-ray diffraction. It crystallizes within the orthorhombic space group Fdd2, with the following cell constants: a = 18.2930(2) Å; b = 18.6430(5) Å; c = 6.5860(5) Å; V = 2246.07(18) Å³. The three-dimensional framework of this hydrated aluminosilicate zeolite is made up by chains of corner-sharing SiO₄ and AlO₄ tetrahedra down c; the chains are held together by sharing the external vertices of tetrahedra; water molecules and Na⁺ extra-framework cations fill up the resulting cavities, the latter forming irregular NaO₆ octahedra. Hydrogen bonds complete the array.     

Rietveld Refinement of the Crystal Structure of Nickel Hexaamina Perchlorate and -Tetrafluorborate

Room-temperature phases of nickel hexamina perchlorate (NHP) and nickel hexaamina tetrafluorborate (NHT) were analysed by means of X-ray powder diffractometry. Both compounds crystallize in the cubic system (Fm3 m space group) with cell parameters: a = 11.4689 Å for NHP and a = 11.2692 Å for NHT structure, respectively. The crystal structures of these compounds were refined using Rietveld method.     

Synthesis,Crystal Structure,and Free Radical Scavenging Activity of 4-Aminopyridinium 3,5-Dinitrobenzoate

The crystal structure of 4-aminopyridinium 3,5-dinitrobenzoate, C₁₂H₁₀O₆N₄, has been determined by single-crystal X-ray diffraction technique. The title compound crystallizes in the monoclinic sp. gr. P21/n with the unit cell parameters: a = 7.4726(3) Å, b = 23.0898(9) Å, c = 8.0744(4) Å, V = 1338.64(10) ų, Z = 4. The asymmetric unit of the compound consists of one 3,5-dinitrobenzoate anion and 4-aminopyridine cation. The adjacent anions and cations are linked through two N?H···O hydrogen bonds, N2?H2A···O5 and N₂?H2B···O6, to form an infinite chain of anions and cations, extended along the [010] direction.     

水热合成NiS2粉晶及Rietveld结构精修

采用水热法一步合成了二硫化镍粉晶,利用XRD、SEM对样品进行了表征并使用Rieteveld粉末衍射峰形全谱拟合方法对不同水热反应条件下合成二硫化镍粉晶的晶体结构进行了研究.并用多相全谱拟合相定量分析法对水热合成二硫化镍粉晶中的杂相质量百分比进行了计算,分析了NiS2粉晶的合成机理.     

Extraction and Crystal Structure of Fucosterol

Crystallography Reports - The compound of fucosterol (C29H48O), an active phytosterol present in many edible marine algae, has been characterized by X-ray diffraction and extensive nuclear magnetic...     

Crystal and Molekular Structure of Piperidinium-acet-p-Cl-anilide-chloride

Piperidinium-acet-p-Cl-anilide-chloride crystallizes in the triclinic space group P 1 with 2 formula units C₁₃H₁₈ON₂Cl₂ in the unit cell. The lattice constants are a = 10.471 Å, b = 12.545 Å, c = 6.149 Å, α = 72.14°, β = 105.70° and γ = 105.21°. Bond lengths, bond angles and the conformational flexibility were determined by X-ray structure analysis. The crystal structure contains dimeres consisting of drug molecules connected by hydrogen bonds.     

Crystal and Molecular Structure of Piperidinium-acet-m-Cl-anilide-chloride

Piperidinium-acet-m-Cl-anilide-chloride crystallizes in the orthorhombic space group Pca2₁ with 4 formula units C₁₃H₁₈ON₂Cl₂ in the unit cell. The lattice parameters are a = 10.348 Å, b = 12.280 Å and c = 11.335 Å. The crystal structure was determined by the heavy atom method and refined by least-squares procedures to the conventional R = 0.045. Bond lengths, bond angles and the conformation of the drug molecule were determined. Cl⁻ ions are linked to the molecules by hydrogen bonds forming chains together with iones and molecules related by the a-glide plane.     

Crystal and Molecular Structure of Desmodin

The crystal structure of the title compound has been determined from X‐ray diffraction. The compound crystallizes from benzene in the orthorhombic system, space group P2₁2₁2₁, with unit cell parameters: a = 8.485(2), b = 9.816(2), c = 22.597(4) Å, Z = 4, V = 1881.9(7) ų. The structure was determined by direct methods and refined to a final R‐factor of 0.04. Six membered rings B and E are planar. Ring A and ring C are in slightly distorted sofa conformation. Ring D is in envelope conformation. The structure is stabilised by weak intermolecular C‐H...O hydrogen bonds.     

Crystal and Molecule Structure of Piperidino-acet-m-Bromo-Anilide

The compound piperidino-acet-m-bromo-anilide crystallizes in the orthorhombic space group Pbca with 8 molecules in the unit cell of dimensions a = 23.656; b = 12.664; c = 9.372 Å. The crystal structure was determined. The positions of all hydrogen atoms were located. The intermolecular hydrogen bond N(1)-H(N1)… 0 has an influence on the conformation of the molecule. The angle between the plane of the phenyl ring and the plane of the carbonamide group is 36.8°.     

Crystal Growth from Silica Gels and Single Crystal Structure of Bariumchromate

Rhombic single crystals of bariumchromate were grown in silica gels up to 1.5 mm in size. The influence of the initial pH-value of the gel and the kind and concentration of reactants are studied. The crystal structure has been determined. The compound crystallizes in space group Pnma, with cell dimensions a = 9.113(4) Å, b = 5.528(3) Å, c = 7.336(4) Å and Z = 4. The structure was refined to R = 0.062 on the basis of 364 reflections. Every barium atome, centered in a distorted archimedian antiprism, is coordinated to 8 oxygen atoms each belonging to a chromate tetrahedron. Interatomic distances and bond angles were calculated.     

Crystal Structure of Rabdoternin A

Abstract  

Rabdoternin A is a natural diterpenoid isolated from Rabdosia rubescen and its crystal structure was determined by X-ray single crystal diffraction. The compound compactly packs in an orthorhombic unit cell in the P2₁2₁2₁ space group with unit cell dimensions a = 7.9200(10) ?, b = 11.2411(14) ?, c = 20.474(2) ?, V = 1822.8(4) ?³ and Z = 4. Two intermolecular hydrogen bonds assemble the title compound into infinite two-dimensional networks along (001) plane.     

反应烧结法合成铁铝尖晶石晶体的XRD结构精修

以分析纯氧化铁和分析纯氧化铝为原料,按照质量比Fe2O3∶Al2O3 =44∶56进行配料,压制成φ25 mm×35mm试样.成型后的试样在保护气氛下加热至1600℃并保温6h.用XRD、SEM、EDS和XPS等对试样进行了表征和分析.结果表明:于1600℃和保护气氛条件下合成了高纯度铁铝尖晶石,且为均—物相,其中的铁离子主要以+2形式存在;Fe2、Al3均在尖晶石结构中的四面体和八面体位置有所占位,XRD结构精修给出其结构式为(Fe0.837 Al0.163)Ⅳ(Fe0.163Al1.837)ⅥO4 000.