scholarly journals Luminescent properties of Eu-doped magnetic Na3FeF6

RSC Advances ◽  
2018 ◽  
Vol 8 (67) ◽  
pp. 38410-38415 ◽  
Author(s):  
Hong Jia ◽  
Yiping Zhou ◽  
Xiaoyan Wang ◽  
Weiying Zhang ◽  
Xun Feng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Luminescent Properties ◽  
Monoclinic Crystal ◽  
Space Group ◽  
Iron Fluoride ◽  
Structure Space ◽  
Monoclinic Crystal Structure

Sodium iron fluoride (Na3FeF6) is a colorless ferromagnetic fluoride with a monoclinic crystal structure (space group P21/c), and it is expected to be an ideal platform for exploring magneto-optical interactions.

scholarly journals Crystal Structures of New Ivermectin Pseudopolymorphs

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 172
Author(s):  
Kirill Shubin ◽  
Agris Bērziņš ◽  
Sergey Belyakov
Keyword(s):  
Crystal Structure ◽  
Molecular Conformation ◽  
Methyl Tert Butyl Ether ◽  
Minor Role ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
Structure Space

New pseudopolymorphs of ivermectin (IVM), a potential anti-COVID-19 drug, were prepared. The crystal structure for three pseudopolymorphic crystalline forms of IVM has been determined using single-crystal X-ray crystallographic analysis. The molecular conformation of IVM in crystals has been compared with the conformation of isolated molecules modeled by DFT calculations. In a solvent with relatively small molecules (ethanol), IVM forms monoclinic crystal structure (space group I2), which contains two types of voids. When crystallized from solvents with larger molecules, like γ-valerolactone (GVL) and methyl tert-butyl ether (MTBE), IVM forms orthorhombic crystal structure (space group P212121). Calculations of the lattice energy indicate that interactions between IVM and solvents play a minor role; the main contribution to energy is made by the interactions between the molecules of IVM itself, which form a framework in the crystal structure. Interactions between IVM and molecules of solvents were evaluated using Hirshfeld surface analysis. Thermal analysis of the new pseudopolymorphs of IVM was performed by differential scanning calorimetry and thermogravimetric analysis.

Electron density, disorder and polymorphism: high-resolution diffraction studies of the highly polymorphic neuralgic drug carbamazepine

2016 ◽  
Vol 72 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Ioana Sovago ◽  
Matthias J. Gutmann ◽  
Hans Martin Senn ◽  
Lynne H. Thomas ◽  
Chick C. Wilson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Diffraction Data ◽  
Structural Formula ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Monoclinic Crystal Structure

Analysis of neutron and high-resolution X-ray diffraction data on form (III) of carbamazepine at 100 K using the atoms in molecules (AIM) topological approach afforded excellent agreement between the experimental results and theoretical densities from the optimized gas-phase structure and from multipole modelling of static theoretical structure factors. The charge density analysis provides experimental confirmation of the partially localized π-bonding suggested by the conventional structural formula, but the evidence for any significant C—N π bonding is not strong. Hirshfeld atom refinement (HAR) gives H atom positional and anisotropic displacement parameters that agree very well with the neutron parameters. X-ray and neutron diffraction data on the dihydrate of carbemazepine strongly indicate a disordered orthorhombic crystal structure in the space groupCmca, rather than a monoclinic crystal structure in space groupP21/c. This disorder in the dihydrate structure has implications for both experimental and theoretical studies of polymorphism.

TEM of twinning in alpha and beta phase plutonium

1990 ◽  
Vol 48 (4) ◽  
pp. 1014-1015
Author(s):  
T. G. Zocco ◽  
R. I. Sheldon ◽  
H. F. Rizzo
Keyword(s):  
Crystal Structure ◽  
Beta Phase ◽  
Alpha Phase ◽  
Unit Cell ◽  
Phase Identification ◽  
Orientation Relationships ◽  
Monoclinic Crystal ◽  
Space Group ◽  
Monoclinic Crystal Structure ◽  
Β Phase

Twinning in α and β phase Pu has been studied by Transmission Electron Microscopy (TEM) to experimentally determine active twinning systems in this complex metal. Twinning in alpha phase Pu was studied in 2 specimens including a triode sputter deposited film, and a partially transformed (α+δ phase) Pu nominally lwt% Ga alloy. A thick film of metastable beta phase was also obtained by triode sputter deposition. Phase identification of all samples was determined from x-ray diffraction patterns. Alpha phase has a monoclinic crystal structure with 16 atoms per unit cell and a P21/m space group. Beta phase has a body-centered monoclinic crystal structure with 34 atoms per unit cell and an I2/m space group.Parent/twin orientation relationships were determined by electron diffraction pattern analysis, stereographic projection analysis and fundamental crystallographic calculations.A computer program was also developed to search for all possible twinning systems in α Pu.

scholarly journals The luminescence properties of yttria based phosphors and study of YBO3 formation via H3BO3 addition

2018 ◽  
Vol 12 (3) ◽  
pp. 262-267 ◽  
Author(s):  
Seyed Rafiaei
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Boric Acid ◽  
Luminescence Properties ◽  
Monoclinic Crystal ◽  
Solid State Method ◽  
Space Group ◽  
Monoclinic Crystal Structure ◽  
State Method ◽  
Nano Phosphor

In this paper, Y2O3:Eu3+ nano-phosphor was synthesized through the facile solid-state method and influence of H3BO3 addition to the prepared Y2O3:Eu3+ powder was investigated. The consumption of boric acid resulted in the formation of YBO3 by changing the crystal structure from cubic to hexagonal. Noteworthy, through the use of specific quantities of H3BO3 (medium amount), Y3BO6 impurity with the monoclinic crystal structure and the space group C2/m was formed. FESEM observations showed that the addition of H3BO3 leads to the coarsening of the synthesized particles; changing from approximately 80 nm to 1 ?m. Also, it was concluded that the transformation of the crystal structure causes a dramatic change of phosphor emission colours from reddish to orange.

Effects of Glycine on the Properties of the Long Afterglow Phosphor CaAl2O4:Eu2+, Nd3+ Prepared by Combustion Synthesis

2011 ◽  
Vol 396-398 ◽  
pp. 284-287
Author(s):  
Xiao Xia Liu ◽  
Hai Lian Qin ◽  
Gui Hua Peng ◽  
Zhen Hua Liang
Keyword(s):  
Crystal Structure ◽  
Combustion Synthesis ◽  
Luminescent Properties ◽  
Combustion Products ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Long Afterglow ◽  
Monoclinic Crystal Structure ◽  
Afterglow Time

The long afterglow phosphor CaAl2O4: Eu2+, Nd3+ was prepared by combustion synthesis, and the influence of glycine on the luminescent properties of the long afterglow phosphor was studied. The samples were characterized by X-ray diffraction (XRD) and fluorescence spectroscopy (PL) etc. The results showed that the main phase of the combustion products is CaAl2O4 with monoclinic crystal structure. The introduction of glycine prolongs the afterglow time.

Diaquaiodidotetrasarcosinepotassium: an overview of sarcosine metal halogenide structures

2012 ◽  
Vol 69 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Michel Fleck ◽  
Vahram V. Ghazaryan ◽  
Aram M. Petrosyan
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Potassium Iodide ◽  
Monoclinic Crystal ◽  
Space Group ◽  
Short Overview ◽  
Monoclinic Crystal Structure

The monoclinic crystal structure of tetrasarcosine potassium iodide dihydrate {orcatena-poly[[potassium-tetra-μ-sarcosine-κ4O:O′;κ4O:O] iodide dihydrate]}, {[K(C3H7NO2)4]I·2H2O}nor Sar4·KI·2H2O (space groupC2/c), comprises two crystallographically different sarcosine molecules and one water molecule on general positions, and one K+cation and one I−anion located on twofold axes. The irregular eight-coordinated K+polyhedra are connected into infinite chains along [001]viasarcosine molecules. This compound is the first sarcosine metal halogenide salt with a 4:1 ratio. A short overview of other sarcosine metal halogenide salts is presented and relationships to similar glycine salts are discussed.

scholarly journals (R)-Baclofen [(R)-4-amino-3-(4-chlorophenyl)butanoic acid]

2022 ◽  
Vol 78 (1) ◽  
Author(s):  
Feodor Belov ◽  
Alexander Villinger ◽  
Jan von Langermann
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Title Compound ◽  
Single Crystal Xrd ◽  
Butanoic Acid ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
Structure Space

This article provides the first single-crystal XRD-based structure of enantiopure (R)-baclofen (form C), C10H12ClNO2, without any co-crystallized substances. In the enantiopure title compound, the molecules arrange themselves in an orthorhombic crystal structure (space group P212121). In the crystal, strong hydrogen bonds and C—H ... Cl bonds interconnect the zwitterionic molecules.

Ein tricyclisches Tetraboradisiladodecan aus Dimethyl-di-1-propinylsilan und Ethyldiboranen(6) / A Tricyclic Tetraboradisiladodecane from Dimethyl-di-1-propynylsilane and Ethyldiboranes(6)

1995 ◽  
Vol 50 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Roland Köster ◽  
Günter Seidel ◽  
Roland Boese ◽  
Bernd Wrackmeyer
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Thermal Elimination

The exhaustive hydroboration of the (C ≡ C )-groups in Me2Si(C ≡ CMe)2 (A ) by adding ethyldiboranes(6) at room temperature is presumed to lead initially to the formation of a mixture of the threo- and erythro-3,3,5,6-tetrakis(diethylboryl)-4,4-dimethyl-4-silaheptanes (1a , b). The threo-1a reacts further by borane catalysed intermolecular condensation to the substituted disilatetraboratricyclo[6.2.1.16.9]dodecane 2 with the formula , whose crystal structure [space group C2/c, a = 19.696(2), b = 10.371(1), c = 16.580(2) Å; β = 125.90(1)°; at 122 K] has been established by X -ray diffraction. In contrast, the erythro-1b undergoes intramolecular, thermal elimination of Et3B to give the 1,2-diethyl-2,4-bis(diethylboryl)- 3,3,5-trim ethyl-3-silaborolane (4). If A is added to an excess of undiluted B (“hydridebath”), then the two substituted diastereomers of the 1-carba-arachno-pentaboranes(10) (endo/exo-Et,SiH Me2) (3a, b), are formed preferentially as the result of an initial Si-C ≡-c le a v e d hydroboration.

Darstellung und Struktur der Verbindungen MgCuP, BaCuP(As) und BaAgP(As) / Preparation and Crystal Structure of MgCuP, BaCuP(As), and BaAgP(As)

1979 ◽  
Vol 34 (10) ◽  
pp. 1373-1376 ◽  
Author(s):  
Albrecht Mewis
Keyword(s):  
Crystal Structure ◽  
Space Group ◽  
Lattice Constants ◽  
Structure Space

Abstract The ABX-compounds MgCuP, BaCuP(As) and BaAgP(As) have been prepared and their structures determined. MgCuP crystallizes orthorhombically in an anti-PbCl2-structure (space group Pnma-D162h, a = 653.2(1) pm, b - 383.5(1) pm, c = 717.0(1) pm). The compounds BaCuP(As) and BaAgP(As) are isotypic and crystallize in a modified Ni2ln-structure (space group P63/mmc-D46h) with the lattice constants:BaCuP a = 423.9(1) pm, c = 900.6(2) pm,BaCuAs a = 437.2(1) pm, c = 907.3(2) pm,BaAgP a = 449.6(1) pm, c = 882.8(2) pm,BaAgAs a = 461.3(1 )pm, c = 889.6(1) pm.

Preparation, Crystal Structure, and Properties of the Lanthanoid Carbides Ln4C7 with Ln = Ho, Er, Tm, and Lu

1996 ◽  
Vol 51 (5) ◽  
pp. 646-654 ◽  
Author(s):  
Ralf Czekalla ◽  
Wolfgang Jeitschko ◽  
Rolf-Dieter Hoffmann ◽  
Helmut Rabeneck
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Magnetic Ordering ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Monoclinic Crystal Structure ◽  
Arc Melting ◽  
Structure Factors ◽  
Hydrolysis Of

The isotypic carbides Ln4C7 (Ln = Ho, Er, Tm, Lu) were prepared by arc-melting of the elemental components, followed by annealing at 1300 °C. The positions of the metal and of some carbon atoms of the monoclinic crystal structure of LU4C7 were determined from X-ray powder data, and the last carbon positions were found and refined from neutron powder diffraction data: P21/c, a = 360.4(1), b = 1351.4(3), c = 629.0(2) pm, β = 104.97(2)°, Z = 2, R = 0.026 for 429 structure factors and 15 positional parameters. The structure contains isolated carbon atoms with octahedral lutetium coordination and linear C3-units, with C-C bond lengths of 132(1) and 135(1) pm. This carbide may therefore be considered as derived from methane and propadiene. The hydrolysis of LU4C7 with distilled water yields mainly methane and propine, while the hydrolyses of the corresponding holmium and erbium carbides resulted in relatively large amounts of saturated and unsaturated C2-hydrocarbons in addition to the expected products methane and propine. The structure comprises two-dimensionally infinite NaCl-type building elements, which are separated by the C3-units. It may be described as a stacking variant of a previously reported structure of HO4C7, now designated as the a-modification. The Lu4C7-type β -modification was obtained at higher temperatures. Its structure was refined by the Rietveld method from X-ray powder data to a residual R = 0.037 for 320 F values and 15 positional parameters. Lu4C7 is Pauli paramagnetic; β -HO4C7 and Er4C7 show Curie-Weiss behavior with magnetic ordering temperatures of less than 20 K.

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