scholarly journals Twist Tetrahedral-Tilting Structure Built from Photoluminescent Cadmium Chalcogenide Clusters

2020 ◽  
Author(s):  
Wen-Chia Wu ◽  
Chung-Sung Yang ◽  
Yan Xu
Keyword(s):  
Solid State ◽  
Cell Volume ◽  
Room Temperature ◽  
Unit Cell ◽  
Chalcogenide Clusters ◽  
Crystal Cell ◽  
Cadmium Chalcogenide ◽  
State Luminescence

The newly synthesized cadmium chalcogenide ternary cluster is composed by six [S3Se]2− tetrahedron units, coordinated with six Cd2+ cations. The potential cavity, calculated by the PLATON program, occupied 38.1% of crystal cell volume. The charge of unit cell is neutral. Therefore, the unit cell formula is determinate as [Cd6S18Se6]. Two strong solid-state luminescence peaks, centered at 450 nm and 498 nm, were observed from the ternary [Cd6S18Se6] clusters by λ = 370 nm radiation. The 450 nm peak is due to the porosity property of cadmium chalcogenide clusters. However, the 498 nm peak has not been reported for the cadmium chalcogenide clusters before. In this study, we demonstrate that the 498 nm peak is attributed to the embedded Se atoms confined in the [S3Se]2− unit of [Cd6S18Se6] cluster. The luminescent output from the ternary [Cd8S18Se6] cluster is stable in room temperature for more than 6 months.

scholarly journals A new zinc(II) supramolecular square: Synthesis, crystal structure, thermal behavior and luminescence

2015 ◽  
Vol 80 (10) ◽  
pp. 1289-1295
Author(s):  
Xiu-Yan Wang ◽  
Zhong-Yu Zhao ◽  
Qian Han ◽  
Miao Yu ◽  
De-Yu Kong
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Thermal Behavior ◽  
Luminescence Property ◽  
Room Temperature ◽  
Hydrothermal Condition ◽  
Stacking Interactions ◽  
Triclinic Space Group ◽  
Four Corners ◽  
State Luminescence

A new square-shaped Zn(II) complex, namely, [Zn4(L)4(phen)4]?6H2O (1) (L = 2-hydroxynicotinate and phen = 1,10- phenanthroline), has been synthesized under hydrothermal condition. The crystal of 1 belongs to triclinic, space group P -1 with a = 10.773(2) ?, b = 12.641(3) ?, c = 13.573(3) ?, ? = 107.44(3)?, ? = 102.66(3)?, ? = 93.89(3)?, C72H56N12O18Zn4, Mr = 1638.77, V = 1702.8(6) ?3 , Z = 1, Dc = 1.598 g/cm3 , S = 1.045, ?(MoK?) = 1.475 mm-1 , F(000) = 836, R = 0.0472 and wR = 0.0919. In 1, four L ligands bridge four Zn(II) atoms to form a square-shaped structure, where four phen ligands are respectively located on four corners of the square. The ?-? stacking interactions extend the adjacent squares into a 1D supramolecular chain. The thermal behavior of 1 has been characterized. Moreover, its solid state luminescence property has been studied at room temperature.

A low-temperature polymorph ofm-quinquephenyl

2012 ◽  
Vol 68 (12) ◽  
pp. o492-o497 ◽  
Author(s):  
Ligia R. Gomes ◽  
R. Alan Howie ◽  
John Nicolson Low ◽  
Ana S. M. C. Rodrigues ◽  
Luís M. N. B. F. Santos
Keyword(s):  
Low Temperature ◽  
Cell Volume ◽  
Room Temperature ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Geometric Parameters ◽  
Asymmetric Unit ◽  
Cell Axis ◽  
Space Group ◽  
Π Interactions

A low-temperature polymorph of 1,1′:3′,1′′:3′′,1′′′:3′′′,1′′′′-quinquephenyl (m-quinquephenyl), C30H22, crystallizes in the space groupP21/cwith two molecules in the asymmetric unit. The crystal is a three-component nonmerohedral twin. A previously reported room-temperature polymorph [Rabideau, Sygula, Dhar & Fronczek (1993).Chem. Commun.pp. 1795–1797] also crystallizes with two molecules in the asymmetric unit in the space groupP\overline{1}. The unit-cell volume for the low-temperature polymorph is 4120.5 (4) Å3, almost twice that of the room-temperature polymorph which is 2102.3 (6) Å3. The molecules in both structures adopt a U-shaped conformation with similar geometric parameters. The structural packing is similar in both compounds, with the molecules lying in layers which stack perpendicular to the longest unit-cell axis. The molecules pack alternately in the layers and in the stacked columns. In both polymorphs, the only interactions between the molecules which can stabilize the packing are very weak C—H...π interactions.

Structural analysis of lead magnesium niobate using synchrotron powder X-ray diffraction and the Rietveld method

2016 ◽  
Vol 72 (3) ◽  
pp. 404-409 ◽  
Author(s):  
Ashok Bhakar ◽  
Adityanarayan H. Pandey ◽  
M. N. Singh ◽  
Anuj Upadhyay ◽  
A. K. Sinha ◽  
...  
Keyword(s):  
Cell Volume ◽  
Room Temperature ◽  
Unit Cell Volume ◽  
Rietveld Method ◽  
Unit Cell ◽  
Lead Magnesium Niobate ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Magnesium

The room-temperature synchrotron powder X-ray diffraction pattern of the single phase perovskite lead magnesium niobate (PMN) has shown significant broadening in theqrange ∼ 5–7 Å−1compared with standard LaB6synchrotron powder X-ray diffraction data, taken under similar conditions. This broadening/asymmetry lies mainly towards the lower 2θ side of the Bragg peaks. Attempts to fit this data with the paraelectric cubic phase (Pm\bar 3m) and the local rhombohedral phase (R3m) corresponding to polar nanoregions (PNRs) are made using the Rietveld method. Rietveld refinements show that neither cubic (Pm\bar 3m) nor rhombohedral (R3m) symmetry can fit this XRD pattern satisfactorily. The two-phase refinement fits the experimental data satisfactorily and suggests that the weight percentage of the PNRs is approximately 12–16% at room temperature. The unit-cell volume of these rhombohedral PNRs is approximately 0.15% larger than that of the unit cell volume of the paraelectric cubic phase.

The Effect of Substituting Ga for Alon Crystal Structure of Phosphors MAl 2Si2O8: Eu2+ (M= Ca, Sr, Ba)

2022 ◽  
Vol 905 ◽  
pp. 91-95
Author(s):  
Fei Wang ◽  
Hui Hui Chen ◽  
Shi Wei Zhang
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Cell Volume ◽  
Solid Solutions ◽  
Solid State Reaction ◽  
Unit Cell Volume ◽  
Lattice Parameter ◽  
Unit Cell ◽  
Lattice Parameters ◽  
Reductive Atmosphere

A series of luminescence phosphors M0.955Al2 –xGaxSi2O8∶Eu2+ (M=Ca, Sr, Ba, x = 0~1.0) were prepared via solid-state reaction in weak reductive atmosphere. The lattice positions were discussed. It was found that when Ga3+ entered MAl2Si2O8 lattice and substituted Al3+, complete solid solutions formed. The lattice parameters (a, b, c) and unit cell volume of phosphors M 0.955Al2 –xGaxSi2O8: Eu2+ (M=Ca, Sr, Ba, x = 0~1.0) increased linearly, the lattice parameters (α, β,γ) of Ca0.955Al2–xGaxSi2O8∶Eu2+(CAS) decreased linearly and the lattice parameter β of Sr0.955Al2–xGaxSi2O8∶Eu2+(SAS) and Ba0.955Al2–xGaxSi2O8∶Eu2+(BAS) increased linearly as Ga3+ content increased.

In situ XRPD study of the ambient-pressure synthesis of nonstoichiometric Ag3O from Ag–Ag2O thin films: Phase abundance, unit-cell parameters, and c/a as a function of temperature and time

2020 ◽  
Vol 35 (4) ◽  
pp. 247-261
Author(s):  
Paul J. Schields ◽  
Nicholas Dunwoody ◽  
David Field ◽  
Zachary Wilson
Keyword(s):  
Thin Films ◽  
Cell Volume ◽  
Room Temperature ◽  
Unit Cell Volume ◽  
Ambient Pressure ◽  
Thermal Reaction ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters

Ag3O was synthesized by jet-milling magnetron-sputtered Ag–Ag2O thin films. Heating the jet-milled powders in air and N2 from 40 to 148 °C at ambient pressure produced Ag3O-rich powders. The phase composition and unit-cell parameters of the jet-milled powders were measured as a function of temperature with in situ X-ray powder diffraction experiments from −186 to 293 °C. Ag3O was also produced by ball milling and sonicating jet-milled films at ambient conditions. The phase composition, unit-cell parameters, and thermal-reaction rates indicate nonstoichiometric Ag3O was produced from the reaction of metastable, nonstoichiometric Ag2O (cuprite structure) and ccp Ag. The thermal expansion of Ag3O is anisotropic; below 25 °C, the a-axis expansion is about twice the c-axis expansion resulting in a negative slope of c/a(T). The reversal of the sign of c/a(T) near 25 °C is dramatic. The thermal reaction is arrested when the temperature is rapidly increased from ambient to 130 °C. Ag3O is metastable and decreases its unit-cell volume during kinetic decomposition to Ag when heated above ambient temperature in air and nitrogen. The relative volume expansion of Ag3O is about 80% less than Ag at room temperature and below. The suite of nonstoichiometric Ag3O produced by heating displays a linear relation between c/a and unit-cell volume at room temperature. The c/a and unit-cell volume of a hydrothermally grown Ag3O single crystal reported in a published structure determination was the Ag-rich, low-volume end member of the linear series. The c/a and unit-cell volume are sensitive indicators of the oxygen content and state of disorder.

Improved Sol-Gel Materials for Efficient Solid State Dye Lasers

1993 ◽  
Vol 329 ◽  
Author(s):  
Michael Canva ◽  
Patrick Georges ◽  
Jean-Fran^ois Perelgritz ◽  
Alain Brun ◽  
Fréddric Chaput ◽  
...  
Keyword(s):  
Solid State ◽  
Physical Properties ◽  
Room Temperature ◽  
Sol Gel ◽  
Tunable Lasers ◽  
Optical Quality ◽  
Dye Lasers ◽  
Laser Dyes ◽  
Host Matrix ◽  
Host Matrices

AbstractPhotoresistant laser dyes were trapped in silica based xerogel host matrices to obtain solid state tunable lasers. For this purpose very dense xerogel samples with improved chemical and physical properties were prepared at room temperature by the sol-gel technology. The as-prepared materials were polished to obtain optical quality surfaces and were used as new lasing media.Lasing action of such different dyes as rhodamine, perylene and pyrromethene doping dense sol-gel matrices was demonstrated. Efficiencies of 30 % or lifetimes of more than 100,000 shots were achieved with different new ≤dye dopant/host matrix≥ couples. Their different performances are reviewed and discussed.

X-ray Structure Refinement and Vibrational Spectroscopy of Ca8Gd2 (PO4)6 O2

2013 ◽  
Vol 12 (10) ◽  
pp. 719-726
Author(s):  
R. Ayadi ◽  
Mohamed Boujelbene ◽  
T. Mhiri
Keyword(s):  
Solid State ◽  
General Formula ◽  
Vibrational Spectroscopy ◽  
Powder Diffraction ◽  
Infrared Spectra ◽  
Solid State Reaction ◽  
Structure Refinement ◽  
Unit Cell ◽  
Cell Group ◽  
X Ray

The present paper is interested in the study of compounds from the apatite family with the general formula Ca10 (PO4)6A2. It particularly brings to light the exploitation of the distinctive stereochemistries of two Ca positions in apatite. In fact, Gd-Bearing oxyapatiteCa8 Gd2 (PO4)6O2 has been synthesized by solid state reaction and characterized by X-ray powder diffraction. The site occupancies of substituents is0.3333 in Gd and 0.3333 for Ca in the Ca(1) position and 0. 5 for Gd in the Ca (2) position.  Besides, the observed frequencies in the Raman and infrared spectra were explained and discussed on the basis of unit-cell group analyses.

Imidazole Promoted Efficient Anomerization of β-D-Glucose Pentaacetate in Organic Solutions and Solid State

2019 ◽  
Author(s):  
Meifeng Wang ◽  
Liyin Zhang ◽  
Yiqun Li ◽  
Liuqun Gu
Keyword(s):  
Solid State ◽  
Organic Solvents ◽  
Room Temperature ◽  
Materials Design ◽  
The Future ◽  
Organic Solutions ◽  
Glucose Pentaacetate

<p></p>Anomerization of glycosides were rarely performed under basic condition due to lack of efficiency. Here an imidazole promoted anomerization of β-D-glucose pentaacetate was developed; and reaction could proceed in both organic solvents and solid state at room temperature. Although mechanism is not yet clear, this unprecedent mild anomerization in solid state may open a new promising way for stereoseletive anomerization of broad glucosides and materials design in the future..

Fabrication and study the effect of the laser on the properties of the compound Tl2-xHgxBa2-ySryCa2Cu3O10+δ superconductor

2018 ◽  
pp. 168
Author(s):  
A. Kareem Dahash Ali ◽  
Nihad Ali Shafeek
Keyword(s):  
Transition Temperature ◽  
Solid State ◽  
Hydrostatic Pressure ◽  
Electrical Properties ◽  
Co2 Laser ◽  
Temperature Shift ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electrical Properties

This study included the fabrication of    compound (Tl2-xHgxBa2-ySryCa2Cu3O10+δ) in a manner solid state and under hydrostatic pressure ( 8 ton/cm2) and temperature annealing(850°C), and determine the effect of the laser on the structural and electrical properties elements in the compound, and various concentrations of x where (x= 0.1,0.2,0.3 ). Observed by testing the XRD The best ratio of compensation for x is 0.2 as the value of a = b = 5.3899 (A °), c = 36.21 (A °) show that the installation of four-wheel-based type and that the best temperature shift is TC= 142 K  .When you shine a CO2 laser on the models in order to recognize the effect of the laser on these models showed the study of X-ray diffraction of these samples when preparing models with different concentrations of the values ​​of x, the best ratio of compensation is 0.2 which showed an increase in the values ​​of the dimensions of the unit cell a=b = 5.3929 (A °), c = 36.238 (A°). And the best transition temperature after shedding laser is TC=144 K. 

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

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