scholarly journals CO-CRYSTALLIZATION OF C60 AND С70 FULLERENES IN CRYSTAL-SOLVATE [(C70)X+(С60)Y]• TMTSeF•2(C6H6) (х+у=3)

2018 ◽  
Vol 59 (9) ◽  
pp. 21
Author(s):  
Maksim A. Blagov ◽  
Nataliya G. Spitsina ◽  
Sergei V. Konovalikhin
Keyword(s):  
Charge Transfer ◽  
Single Crystals ◽  
Spectral Data ◽  
Fullerene Molecule ◽  
Crystal Solvate ◽  
Organic P ◽  
X Ray ◽  
Ray Patterns ◽  
C60 Fullerenes

The compexation of (С70/C60) fullerenes with organic p-donor of electrons tetramethyl-(tetra selenium)fulvalene (TMTSeF) in benzene (С6Н6) was studied. Comparison of experimental and calculated X-ray patterns showed that in the investigated single crystals of [(C70)x+(С60)y]· TMTSeF·2(C6H6) (х+у=3) (1) С70 and C60 fullerens are co-crystallized. IR spectral data and electroconductivity of 1 indicate the absence of the charge transfer on fullerene molecule for complexes under study.

The analysis of strained surface layers on single crystals utilizing divergent‐beam x‐ray patterns

1981 ◽  
Vol 52 (9) ◽  
pp. 5496-5500 ◽  
Author(s):  
R. J. Schutz ◽  
L. R. Testardi ◽  
S. Weissmann
Keyword(s):  
Single Crystals ◽  
Surface Layers ◽  
Divergent Beam ◽  
X Ray ◽  
Ray Patterns

High-temperature transformation of tridymite single crystals to cristobalite*

1986 ◽  
Vol 175 (3-4) ◽  
Author(s):  
H. Schneider ◽  
O. W. Flörke
Keyword(s):  
High Temperature ◽  
Single Crystals ◽  
Tetrahedral Framework ◽  
X Ray ◽  
Layer Sequence ◽  
Heat Treated ◽  
Parallel Layer ◽  
Temperature Transformation ◽  
Ray Patterns ◽  
Tetrahedral Layer

AbstractThe reconstructive high-temperature transformation of tridymite to cristobalite has been studied with X-ray precession photographs on single crystals. For this purpose inclusion-free and optically untwinned tridymite crystals, separated from a used refractory-grade silica brick were heat-treated between 1500 and 1620°C.The X-ray patterns of the heat-treated tridymite crystals show additional though weak reflections corresponding to those of the pseudo-orthorhombic tridymite TThe close structural relationship between tridymite and cristobalite probably causes a transformation with preservation of structural units. The reconstructive rearrangement of the “antiparallel” tetrahedral layer sequence in tridymite to the “parallel” layer sequence in cristobalite requires rotation and shifting of the tetrahedral layers which occurs by cooperative movements of layer fragments. Complete decomposition of the tridymite tetrahedral framework, and subsequent nucleation and growth of cristobalite is less probable.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Zone-axis ALCHEMI for the rapid assessment of site occupancies in garnets

1986 ◽  
Vol 44 ◽  
pp. 706-707
Author(s):  
M.T. Otten ◽  
P.R. Buseck
Keyword(s):  
Single Crystals ◽  
Rapid Assessment ◽  
Site Occupancy ◽  
Zone Axis ◽  
Synthetic Compounds ◽  
X Ray ◽  
Large Group ◽  
Crystallographic Planes

ALCHEMI (Atom Location by CHannelling-Enhanced Microanalysis) is a TEM technique for determining site occupancies in single crystals. The method uses the channelling of incident electrons along specific crystallographic planes. This channelling results in enhanced x-ray emission from the atoms on those planes, thereby providing the required site-occupancy information. ALCHEMI has been applied with success to spinel, olivine and feldspar. For the garnets, which form a large group of important minerals and synthetic compounds, the channelling effect is weaker, and significant results are more difficult to obtain. It was found, however, that the channelling effect is pronounced for low-index zone-axis orientations, yielding a method for assessing site occupancies that is rapid and easy to perform.

Effect of trytophan as dopant on potassium acid phthalate single crystals

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Visible Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slow Evaporation Technique ◽  
Absorption Studies ◽  
Evaporation Technique ◽  
Potassium Acid Phthalate ◽  
Acid Phthalate

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.

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