Growth and Structural Characterization of Sr2TiO4: Chemical Control Over the Terminating SrTiO3 Surface.

1999 ◽  
Vol 587 ◽  
Author(s):  
P. A. Salvador ◽  
B. Mercey ◽  
O. Perez ◽  
A. M. Haghiri-Gosnet ◽  
T.-D. Doan ◽  
...  
Keyword(s):  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Control ◽  
Plane Film ◽  
Out Of Plane ◽  
Dimensional Growth ◽  
Laser Mbe ◽  
Film Substrate

AbstractThin films of Sr2TiO4 were grown using pulsed laser deposition (PLD) and laser-MBE on [100]-SrTiO3single crystal substrates. Films grown by standard PLD display only a single peak in the X-ray diffraction spectra, corresponding to the (006) peak of the K2NiF4 parent structure. Using a Laser-MBE, controlled two-dimensional growth and RHEED intensity oscillations can be routinely obtained. The period of the RHEED intensity oscillations was confirmed to correspond to the deposition of one-half the unit cell. In contrast to PLD-grown films, the (004) and (006) peaks are observed in XRD spectra for the Laser-MBE-grown films. The intensity of the (004) peak is discussed and modeled with respect to in-plane disorder arising from substrate step-edges and out-of-plane film-substrate structural mismatches. That a single, half unit-cell can be deposited allows one to "flip" the terminating surface of SrTiO3 in a controlled and simple manner from a pure TiO2 layer to a SrO layer. Experimental evidence of the importance of such surface control is given for the SrCuO2 structural stability.

Double Crystal X-Ray Diffraction Measurement of a Triclinicly Distorted and Tilted AlxGa1-xAs Unit Cell Produced by Growth on Offcut GaAs Substrates

1989 ◽  
Vol 159 ◽  
Author(s):  
A. Leiberich ◽  
J. Levkoff
Keyword(s):  
Strain Relaxation ◽  
Growth Direction ◽  
Unit Cell ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Additional Cell ◽  
Additional Strain ◽  
Film Substrate

ABSTRACTCorrections are required for double crystal X-ray diffraction characterization of epitaxial AlxGa1-xAs layers grown on offcut GaAs (100) substrates. Double crystal X-ray diffraction measurements show that the cubic film unit cell defined by Vegard's law is triclinicly distorted and tilted with respect to the substrate unit cell. The distortion and tilt angles oppose each other defining a crystal geometry where the substrate and film <100= axes remain approximately coplanar with the surface normal. This film/substrate crystal geometry leads to formulation of a model describing heteroepitaxy on offcut (100) substrates. When film atoms are bonded to an offcut substrate, the already tetragonaly distorted film unit cell is subjected to additional cell distortions. The magnitude of this additional strain depends on where the film atoms are positioned on a substrate terrace. The first few layers of film atoms establish swain grades across individual substrate terraces. Constrained by the geometry of this interface region and driven by strain relaxation in the net growth direction, subsequent heteroepitaxy forms the measured film/substrate crystal geometry.

scholarly journals Purification and X-ray crystallographic analysis of 7-keto-8-aminopelargonic acid (KAPA) synthase fromMycobacterium smegmatis

2014 ◽  
Vol 70 (10) ◽  
pp. 1372-1375 ◽  
Author(s):  
Shanghua Fan ◽  
Defeng Li ◽  
Joy Fleming ◽  
Yuan Hong ◽  
Tao Chen ◽  
...  
Keyword(s):  
Crystallographic Analysis ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Essential Enzyme ◽  
Mycobacterial Growth

7-Keto-8-aminopelargonic acid synthase (KAPA synthase; BioF) is an essential enzyme for mycobacterial growth that catalyses the first committed step in the biotin-synthesis pathway. It is a pyridoxal 5′-phosphate (PLP)-dependent enzyme and is a potential drug target. Here, the cloning, expression, purification and crystallization of KAPA synthase fromMycobacterium smegmatis(MsBioF) and the characterization of MsBioF crystals using X-ray diffraction are described. The crystals diffracted to 2.3 Å resolution and belonged to the monoclinic space groupP21, with unit-cell parametersa= 70.88,b= 91.68,c= 109.84 Å, β = 97.8°. According to the molecular weight of MsBioF, the unit-cell parameters and the self-rotation function map, four molecules are present in each asymmetric unit with aVMvalue of 2.06 Å3 Da−1and a solvent content of 40.20%.

scholarly journals Synthesis, Crystal Structures and Characterization of Two Nonmetal Cation Tetrafluoroborates

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 812
Author(s):  
Noura Othman Alzamil ◽  
Ghareeba Mussad Al-Enzi ◽  
Aishah Hassan Alamri ◽  
Insaf Abdi ◽  
Amor BenAli
Keyword(s):  
Thermal Analysis ◽  
Hydrofluoric Acid ◽  
Cell Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Microwave Assisted

Two new nonmetal cation tetrafluoroborate phases [H3tren](BF4)3 (I) and [H3tren](BF4)3 HF (II) were synthesized by microwave-assisted solvothermal and characterized by single crystal X-ray diffraction, IR spectroscopy and thermal analysis DTA-TGA. [H3tren](BF4)3 is cubic (P213) with unit cell parameter a = 11.688(1) Å. [H3tren](BF4)3•HF is trigonal (R3c) with unit cell parameters a = 15.297(6) Å and c = 12.007(2) Å. Both (I) and (II) structures can be described from isolated tetrafluoroborate BF4- anions, triprotonated tris-(2-aminoethyl)amine (tren) [H3tren]3+. Phase (II) contains disordered BF4- tetrahedron and hydrofluoric acid.

Synthesis and Characterization of A2CaCuO5(A=Nd, Sm)

1998 ◽  
Vol 12 (11) ◽  
pp. 427-431
Author(s):  
K. Jeyabalan ◽  
L. K. Kaliyaperumal ◽  
A. Sekar ◽  
J. Srinivas
Keyword(s):  
Diffraction Analysis ◽  
Unit Cell ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Cell Parameters

Synthesis and characterization of A 2 CaCuO 5( A=Nd, Sm ) system is reported. Powder X-ray diffraction analysis shows that the compounds crystallizes in an orthorhombic crystal systems and the unit cell parameters are found to be a=6.399(9)Å, b=7.218(8) Å and c=12.167(17) Å for Nd 2 CaCuO 5 and a=5.872(8) Å, b=7.457(3) Å and c=12.682(18) Å for Sm 2 CaCuO 5.

Structural characterization of thin films of the SrBi2Nb2O9ferroelectric Aurivillius phase epitaxially grown on (110)SrTiO3

2003 ◽  
Vol 36 (1) ◽  
pp. 96-102 ◽  
Author(s):  
J.-R. Duclère ◽  
M. Guilloux-Viry ◽  
A. Perrin
Keyword(s):  
Substrate Surface ◽  
A Priori ◽  
Relative Weight ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Aurivillius Phase ◽  
X Ray ◽  
Film Substrate ◽  
Two Peaks

Aurivillius-phase SrBi2Nb2O9(SBN) films grown by pulsed-laser deposition on (110)SrTiO3are nearly (116) oriented as shown by their X-ray diffraction θ–2θ scans. A specific artifact, leading possibly to an erroneous deduction of a (115) and (116) mixture of orientations, has been highlighted. The films present a quite small mosaicity (ω-scan full width at half-maximum = 0.2–0.5°). Sharp electron channeling patterns (ECPs) with the expected twofold symmetry are the signature of film epitaxy. These ECPs often display the superimposition of two individual patterns, rotated by 180° with respect to each other: two families of oriented SBN crystallites, rotated in the same way, coexist in the films. Indeed, from symmetry considerations at the film–substrate interface, these two families area prioriequiprobable. Similarly, two peaks, 180° shifted, are observed for the 00 10 reflection φ scans and fully confirm this model. However, their relative intensity, which gives access to the quantitative distribution of the two families, shows that in many cases the two families do not present the same relative weight, in good correlation with the qualitative ECP observations, indicating a subtle asymmetrization at the nucleation or growth stage. The in-plane orientation is defined as: [\bar{1}10]F|| [001]Sand nearly [33\bar{1}]For [\bar{3}\bar{3}1]F|| [\bar{1}10]S(generating the two families). The film–substrate interfacial relationship is discussed, taking into account the possible facetting of the substrate surface and the occurrence of the (11\bar{7}) SBN plane as twin boundary.

Fabrication and Characterization of PEDOT/Au Films by Chemical Vapor Polymerization Using Au+3 Oxidant

2008 ◽  
Vol 8 (9) ◽  
pp. 4714-4717 ◽  
Author(s):  
Soyeon Kim ◽  
Misuk Cho ◽  
Jaedo Nam ◽  
Youngkwan Lee
Keyword(s):  
Composite Films ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Au Film ◽  
Pet Film ◽  
Vapor Phase Polymerization ◽  
Film Substrate ◽  
Thermal Stability Of

Thin composite films of poly (3,4-ethylenedioxythiophene) (PEDOT)/Au were obtained by a vapor-phase polymerization technique using HAuCl4 as an oxidant on the PET film substrate. The PEDOT/Au films were synthesized with metallic gold originating from the redox reaction between 3,4-ethylenedioxythiophene (EDOT) and Au ions. The formation of the PEDOT/Au film was confirmed by UV-vis absorption spectroscopy and scanning electron microscopy (SEM). The reduction to zero-valent gold was confirmed by X-ray spectrometer (EDX) and X-ray diffraction (XRD). In addition, the enhancement of the thermal stability of the PEDOT/Au film was studied by measuring the change in the conductivity at high temperature. The conductivities of the PEDOT films prepared using FTS and HAuCl4 were 260 and 200 Scm−1 and their thicknesses were 100 and 120 nm, respectively.

scholarly journals Synthesis, structural and spectroscopic characterization of thallium(I) acesulfamate

2015 ◽  
Vol 34 (1) ◽  
pp. 95 ◽  
Author(s):  
Enrique J. Baran ◽  
Beatriz S. Parajón-Costa ◽  
Gustavo A. Echeverría ◽  
Oscar E. Piro
Keyword(s):  
Crystal And Molecular Structure ◽  
Spectroscopic Characterization ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Sodium Potassium ◽  
X Ray ◽  
Cell Parameters ◽  
Cesium Salts

<p><strong>SYNTHESIS, STRUCTURAL AND SPECTROSCOPIC CHARACTERIZATION OF THALLIUM(I) ACESULFAMATE</strong></p><p><strong> </strong></p><p>     The new acesulfamate salt, TlC<sub>4</sub>H<sub>4</sub>NO<sub>4</sub>S, was prepared by reaction of acesulfamic acid and thallium(I) carbonate in aqueous solution.  Its crystal and molecular structure was determined by single crystal X-ray diffraction methods. The substance crystallizes in the monoclinic space group <em>P2<sub>1</sub>/a</em>, with unit cell parameters <em>a </em>= 7.5844(4) Å, <em>b</em> = 9.7268(5) Å, <em>c</em> = 10.8105(5) Å, <em>β</em> = 105.174(6)°, and <em>Z</em>=4 molecules per unit cell, and is isostructural with the corresponding sodium, potassium, rubidium and cesium salts. The FTIR and Raman spectra of the compound are also recorded and briefly discussed.</p>

Characterization of the ionic clathrate hydrate of tetra-n-butylammonium acrylate

2015 ◽  
Vol 93 (9) ◽  
pp. 954-959 ◽  
Author(s):  
Sanehiro Muromachi ◽  
Masato Kida ◽  
Satoshi Takeya ◽  
Yoshitaka Yamamoto ◽  
Ryo Ohmura
Keyword(s):  
Nmr Spectra ◽  
Clathrate Hydrate ◽  
Unit Cell ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Water ◽  
C Nmr ◽  
The Ideal

The ionic clathrate hydrate of tetra-n-butylammonium (TBA) acrylate was characterized using single-crystal X-ray diffraction, elemental analysis, and nuclear magnetic resonance (NMR) spectroscopy. The crystal structure of TBA acrylate was Jeffrey’s type III and tetragonal P42/n, with a 33.076(7) × 33.076(7) × 12.170(2) Å3 unit cell. The volume of the unit cell was 13315(5) Å3, which is almost twice that of the ideal structure. The TBA cation was disordered and located in two types of fused cages. Although the acrylate anion was located in a pentagonal dodecahedral cage neighboring the TBA cation, there is a residual acrylate anion that could be around the other TBA cation in the unit cell. Solid-state 13C NMR spectra showed that the TBA cation was clearly disordered at 173 K, but not at 239 K. NMR peaks from the acrylate anion were not observed at either temperature. This is probably because of the strong restriction on the acrylate anion by hydrogen bonding with the lattice water. Some of the characteristics of the anion and cation of the ionic guest incorporated in the hydrate structure have yet to be defined. Further research is needed to clarify complexation of the ionic clathrate hydrate and the ionic guest, and the resulting structure.

scholarly journals Chemical Preparation, Crystal Structure Reinvestigation and Vibrational Study of CoNa3P3O10.12H2O and X-ray Characterization of the New Anhydrous Triphosphate CoNa3P3O10

2021 ◽  
Vol 12 (2) ◽  
pp. 2586-2602
Keyword(s):  
Ion Exchange Resin ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Compound A ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The triphosphate dodecahydrate of cobalt and sodium CoNa3P3O10.12H2O was prepared by the ion exchange resin process. Its structure was studied by X-ray diffraction and determined in the monoclinic space group P121/c1with the unit-cell parameters a = 14.6650(5) Å, b=9.1916(3) Å, c = 15.0239(5) Å, =90.2210(10) °, Z = 4 and V = 2025.13(12) Å3. The thermal dehydration of this compound was performed, leading to an anhydrous new form, CoNa3P3O10, which was characterized by X-ray diffraction. The obtained CoNa3P3O10 crystallized in monoclinic space group P21/n with the unit-cell parameters a=15,3774 Å, b=7,6988 A°, c=14,2832A°, β=92,9115°.The characteristic IR wavenumbers of the P3O105− ions observed in the vibrational spectra were calculated using isotopic substitutions, which confirms the existence of these groups in the studied compound. A comparison between the IR and Raman wavenumbers of CoNa3P3O10.12H2O, CoNa3P3O10 and Na5P3O10.12H2O was performed. A kinetic study was also made for CoNa3P3O10·12H2O.

Synthesis and X-ray diffraction crystallographic characterization of compound 2-(α-naphtyl)-3-(α-pyridinyl)-1,3-thiazolidin-4-one

2018 ◽  
Vol 33 (3) ◽  
pp. 225-228 ◽  
Author(s):  
J. L. Pinto ◽  
J. A. Henao ◽  
V. Kouznetsov
Keyword(s):  
Mass Spectrometry ◽  
Unit Cell ◽  
Mercaptoacetic Acid ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Biological Aspect ◽  
Monoclinic System ◽  
X Ray ◽  
Wide Range

Thiazolidinones present a wide range of useful applications especially in the biological aspect. Based on these facts, the compound of interest 2-(α-naphthyl)-3-(α-pyridinyl)-1,3-thiazolidine-4-one (C18H14N2OS), was synthesized via multi-component reaction with the aim of obtaining a compound that would show activity against fungi and bacteria. The synthesis of 2-(α-naphthyl)-3-(α-pyridinyl)-1,3-thiazolidine-4-one, was carried out from the respective α-aminopyridine with α-naphthylaldehyde and α-mercaptoacetic acid, under reflux in dry toluene for 8 h, obtaining a solid compound. Molecular characterization of the compound was carried out by infrared spectrometry, mass spectrometry, and nuclear magnetic resonance. The study of the crystallization and the calculation of the unit-cell constants were determined by the technique of X-ray diffraction of polycrystalline samples. It was determined that the compound crystallizes in a monoclinic system with space group P21/c [No. 14] and the constants of the unit cell a = 11.958 (3), b = 9.675 (4), c = 12.661 (4) Å, β = 96.960° (2), V = 1454.01 (Å3).

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