scholarly journals Hydrates of Silver(I) Fluoride and Zinc Chloride

2014 ◽  
Vol 70 (a1) ◽  
pp. C1722-C1722 ◽  
Author(s):  
Laura Folkers ◽  
Nils Trapp ◽  
Jack Dunitz ◽  
Michael Wörle
Keyword(s):  
Heat Storage ◽  
Octahedral Coordination ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Structural Variety ◽  
Trigonal Bipyramidal ◽  
Wide Range ◽  
Heat Storage Materials

Hydrates of transition metal halides are routinely used in a wide range of applications as for example catalysts, electrolytes or heat storage materials[1] . The structural variety ranges from relatively simple structures with isolated coordination polyhedra to complex polymeric frameworks. Surprisingly, many of their crystal structures are still unknown. This is partially due to difficulties of growing and handling single crystals since the hydrates are often highly hygroscopic and deliquescent at ambient temperature. In order to prepare and systematically investigate these compounds by X-ray diffraction, the crystals have to be grown, selected and measured at low temperatures. Using a self-made device[2] to select and transfer the crystals while maintaining the cooling, we were able to grow suitable crystals and determine the structures of AgF·2H2O (trigonal bipyramidal coordination of Ag+ by 4 H2O and one F-), AgF·4H2O (octahedral coordination of Ag+ by 6 H2O) and ZnCl2·3H2O (octahedral coordination of Zn2+by 6 H2O and tetrahedral coordination by 4 Cl-).

Distribution of Cr3+ between octahedral and tetrahedral sites in synthetic blue and green (CaMgSi2O6)95(CaCrAlSiO6)5 diopsides

2019 ◽  
Vol 83 (4) ◽  
pp. 497-505
Author(s):  
Masahide Akasaka ◽  
Yohei Takasu ◽  
Makoto Handa ◽  
Mariko Nagashima ◽  
Maki Hamada ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Rietveld Method ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Tetrahedral Sites ◽  
Bluish Green

AbstractThe distribution of Cr3+ ions in blue and green diopsides crystallised from a glass with the composition [CaMgSi2O6 (Di)]95[CaCrAlSiO6 (CrAlTs)]5 (mol.%) was determined using Rietveld refinement of X-ray diffraction data in order to evaluate published results by optical spectroscopic analysis, and to clarify the influence of Cr3+–Al3+ distribution between the octahedral M1 and tetrahedral T sites on the crystal structure. The starting material was Di95CrAlTs5-diopside crystallised from glass at 800°C for 2 days. After another 19 days at 800°C and 1000°C for 7 days, the diopsides remained blue. The blue diopside gradually changed to bluish green by heating at 1200°C for 3 days and to green after 7 days. The stoichiometric compositions of the synthesised phases were confirmed by electron microprobe analysis. The Cr occupancies refined by the Rietveld method resulted in the site populations in the M1 and T sites: M1[Mg0.95Cr0.030(4)Al0.020]T[Si1.950Cr0.020Al0.030] and M1[Mg0.95Cr0.037(4)Al0.013]T[Si1.950Cr0.013Al0.037] (per 6 oxygens) for the blue diopsides at 800 and 1000°C, respectively: M1[Mg0.95Cr0.042(3)Al0.008]T[Si1.950Cr0.008Al0.042] for the bluish green diopside at 1200°C for 3 days; and M1[Mg0.95Cr0.049(3)Al0.001]T[Si1.950Cr0.001Al0.049] for the green diopside at 1200°C for 7 days. Such Cr and Al distributions effect the volumes and site distortions of the octahedral and tetrahedral coordination polyhedra: the TO4 tetrahedron volumes of the blue diopsides (2.251–2.258 Å3) are larger than that of the green diopside (2.237 Å3); the M1O6 octahedron volumes of the former (11.74–11.77 Å3) are smaller than that of the latter (11.86 Å3); the TO4 tetrahedra in the blue diopside (<λtet> =1.006; σθ(tet)2 = 24.37–24.69) are less distorted than that of the green diopside (<λtet> = 1.007; σθ(tet)2 = 27.94); the M1O6 octahedra in the former (<λoct> =1.006; σθ(oct)2 = 20.39–21.13) are more distorted than that of the latter (<λoct> = 1.005; σθ(oct)2 = 17.58).

Darstellung und Kristallstrukturen von Chloro- und Bromophenylantimonaten(III) [Ph2SbX2] - und [Ph2Sb2X7]3- (X=Cl, Br) / Preparation and Crystal Structures of Chloro- and Bromophenylantimonates(III) [Ph2SbX2]- and [Ph2Sb2X7]3- (X=Cl, Br)

1992 ◽  
Vol 47 (7) ◽  
pp. 919-924 ◽  
Author(s):  
W. S. Sheldrick ◽  
C. Martin
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Halogen Atoms ◽  
Trigonal Bipyramidal ◽  
The Individual

The halophenylantimonates(III) [Ph4P][Ph2SbCl2] (1), [Ph4P][Ph2SbBr2] (2), [Me3NH]3[Ph2Sb2Cl7] (3) and [Me3NH]3[Ph2Sb2Br7] (4) have been prepared and their structures established by single crystal X-ray diffraction. The anions [Ph2SbCl2]- and [Ph2SbBr2]- display w-trigonal bipyramidal geometries with axial halogen atoms. Sb-Cl [2.618(4), 2.601(4)Å] and Sb-Br distances [2.779(3), 2.794(2)A] are very similar to one another in the individual anions of 1 and 2. The anions [Ph2Sb2Cl7]3- and [Ph2Sb2Br7]3- both contain two square pyramidal coordination polyhedra which are vertex-linked to one another via Sb-X-Sb (X=Cl, Br) angles of respectively 152.9(1) and 152.3(1)°; the latter anion displays crystallographic C2-symmetry. trans-Sited Sb-Cl or Sb-Br bond distances in 3 and 4 are structurally correlated to one another.

scholarly journals Anion Induced Synthesis, Structural Characterization and Antibacterial Activity of Zinc(II) Complexes Derived from 5-Bromo-2-((2-(diethylamino)ethylimino)methyl) phenol

2021 ◽  
Vol 68 (3) ◽  
pp. 693-699
Author(s):  
Huan-Yu Liu ◽  
Xiang Gan ◽  
Jin-Yan Ding ◽  
Zhi-Tao Li ◽  
Qiao Chen
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Candida Albicans ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Vis Spectroscopy ◽  
Zinc Salts

By changing the anions of zinc salts, three different zinc(II) complexes, [Zn2(HL)2(NCS)4]·2CH3OH (1), [Zn2L(μ2-η1:η1-CH3COO)2(NCS)] (2) and [Zn(HL)I2]·CH3OH (3), where L = 5-bromo-2-((2-(diethylamino)ethylimino)methyl)phenolate, HL = 5-bromo-2-((2-(diethylammonio)ethylimino)methyl)phenolate, have been synthesized and characterized by IR and UV-Vis spectroscopy, as well as single-crystal X-ray diffraction. X-ray analysis indicates that the Zn atoms in the complexes are in trigonal bipyramidal, square pyramidal and tetrahedral coordination. The anions of the zinc salts lead to the formation of different structures of the complexes. Antibacterial activity of the complexes against Staphylococcus aureus, Escherichia coli, Klebsielle pneumoniae and Candida albicans strains was studied.

scholarly journals Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1786
Author(s):  
Carla Queirós ◽  
Chen Sun ◽  
Ana M. G. Silva ◽  
Baltazar de Castro ◽  
Juan Cabanillas-Gonzalez ◽  
...  
Keyword(s):  
Water Content ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Low Cost ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

Crystal and molecular structure of diorganoammonium oxalatotrimethylstannate, [R2NH2][Me3Sn(C2O4)] (R=i-Bu, cyclohexyl)

2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Diffraction Study ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Trans Complex ◽  
A Chain ◽  
Distorted Trigonal Bipyramidal

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.

2D X-ray diffraction and molecular modelling of the crystalline structure of polyesters under uniaxial stress

2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck
Keyword(s):  
Crystalline Structure ◽  
Molecular Modelling ◽  
Three Dimensional ◽  
Uniaxial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Modelling Techniques ◽  
Diffraction Patterns

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.

scholarly journals A Covalent Organic Cage Compound Acting as a Supramolecular Shadow Mask for the Regioselective Functionalization of C60

2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle
Keyword(s):  
Mass Spectrometry ◽  
Single Crystal ◽  
High Selectivity ◽  
Shadow Mask ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Vis Spectroscopy ◽  
Regioselective Functionalization

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>

scholarly journals Crystal structure refinement of magnesium zinc divanadate, MgZnV2O7, from powder X-ray diffraction data

2021 ◽  
Vol 77 (6) ◽  
pp. 588-591
Author(s):  
Stephanie J. Hong ◽  
Jun Li ◽  
Mas A. Subramanian
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Atomic Ratio ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Wyckoff Position ◽  
Distorted Trigonal Bipyramidal

The crystal structure of magnesium zinc divanadate, MgZnV2O7, was determined and refined from laboratory X-ray powder diffraction data. The title compound was synthesized by a solid-state reaction at 1023 K in air. The crystal structure is isotypic with Mn0.6Zn1.4V2O7 (C2/m; Z = 6) and is related to the crystal structure of thortveitite. The asymmetric unit contains two metal sites with statistically distributed magnesium and zinc atoms with the atomic ratio close to 1:1. One (Mg/Zn) metal site (M1) is located on Wyckoff position 8j and the other (M2) on 4h. Three V sites (all on 4i), and eight O (three 8j, four 4i, and one 2b) sites complete the asymmetric unit. The structure is an alternate stacking of V2O7 layers and (Mg/Zn) atom layers along [20\overline{1}]. It is distinct from other related structures in that each V2O7 layer consists of two groups: a V2O7 dimer and a V4O14 tetramer. Mixed-occupied M1 and M2 are coordinated by oxygen atoms in distorted trigonal bipyramidal and octahedral sites, respectively.

scholarly journals Theoretical study of the properties of X-ray diffraction moiré fringes. II. Illustration of angularly integrated moiré images

2019 ◽  
Vol 75 (4) ◽  
pp. 610-623
Author(s):  
Jun-ichi Yoshimura
Keyword(s):  
Incident Wave ◽  
Angular Width ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Acta Cryst ◽  
Low Contrast ◽  
X Ray ◽  
Moiré Fringes ◽  
Wide Range ◽  
Fringe Patterns

Using a theory of X-ray diffraction moiré fringes developed in a previous paper, labelled Part I [Yoshimura (2015). Acta Cryst. A71, 368–381], the X-ray moiré images of a silicon bicrystal having a weak curvature strain and an interspacing gap, assumed to be integrated for an incident-wave angular width, are simulation-computed over a wide range of crystal thicknesses and incident-wave angular width, likely under practical experimental conditions. Along with the simulated moiré images, the graphs of characteristic quantities on the moiré images are presented for a full understanding of them. The treated moiré images are all of rotation moiré. Mo Kα1 radiation and the 220 reflection were assumed in the simulation. The results of this simulation show that fringe patterns, which are significantly modified from simple straight fringes of rotation moiré, appear in some ranges of crystal thicknesses and incident-wave angular width, due to a combined effect of Pendellösung oscillation and an added phase difference from the interspacing gap, under the presence of a curvature strain. The moiré fringes which slope to the perpendicular direction to the diffraction vector in spite of the assumed condition of rotation moiré, and fringe patterns where low-contrast bands are produced with a sharp bend of fringes arising along the bands are examples of the modified fringe pattern. This simulation study provides a wide theoretical survey of the type of bicrystal moiré image produced under a particular condition.

scholarly journals Charge Compensation in Europium-Doped Hafnia Nanoparticles: Solvothermal Synthesis and Colloidal Dispersion

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1042
Author(s):  
Xavier H. Guichard ◽  
Francesco Bernasconi ◽  
Alessandro Lauria
Keyword(s):  
Low Temperature ◽  
Hafnium Oxide ◽  
Aqueous Media ◽  
Charge Compensation ◽  
Colloidal Dispersion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Direct Formation ◽  
Enhanced Luminescence

Effective charge compensation of europium in hafnium oxide nanoparticles was achieved at low temperature, allowing high doping incorporation (up to 6 at.%) and enhanced luminescence. The efficiency of the incorporation and charge compensation was confirmed by scanning electron microscope energy dispersive X-ray spectroscopy and powder X-ray diffraction measurements. Despite the known polymorphism of hafnium oxide, when doped to a concentration above 3 at.%, only the pure monoclinic phase was observed up to 6 at.% of europium. Furthermore, the low-temperature solvothermal route allowed the direct formation of stable dispersions of the synthesized material over a wide range of concentrations in aqueous media. The dispersions were studied by diffuse light scattering (DLS) to evaluate their quality and by photoluminescence to investigate the incorporation of the dopants into the lattice.

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