scholarly journals An X-ray investigation of the structure of naphthalene and anthracene

1929 ◽  
Vol 125 (798) ◽  
pp. 542-569 ◽  
Keyword(s):  
Crystal Structure ◽  
Geometrical Structure ◽  
Organic Crystals ◽  
X Rays ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Scattering Centre ◽  
Low Symmetry ◽  
Complicated Nature ◽  
Long Chain

In the present paper an attempt is made to develop a geometrical structure factor which will account for the intensity distribution in the various spectra of naphthalene and anthracene. Such an attempt is surrounded by many difficulties owing to the relatively low symmetry of the crystal systems (monclinic), the complicated nature of the molecules, and uncertainties regarding the laws of reflection of X-rays from organic crystals. Recently, however, Dr. Müller has investigated the structure of a long chain hydrocarbon making the simplication of treating a carbon atom and its attendent hydrogen atoms as one scattering centre for X-rays. The success of this investigation makes it seem probable that an approximate structure may likewise be obtained for some of the more complicated aromatic compounds. The simple organic compounds of this type (benzene, cyclohexane) are very often liquids or low melting solids that call for a specialised and difficlut technique in any investigation of their crystal structure. Good crystals of naphthalene and anthracene, however, are easily obtained. Morever the crystal structure of these compounds has already been investigated very fully by Sir William Bragg, both by the ionisation spectrometer and photographic methods. The author has had the privilege of assisting in some of this later work, and the present paper is a continuation of these investigations.

The first proof of protonated anion tetrahedra in the tsumcorite-type compounds

2004 ◽  
Vol 68 (5) ◽  
pp. 757-767 ◽  
Author(s):  
T. Mihajlović ◽  
H. Effenberger
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Single Crystal ◽  
Diffraction Data ◽  
Title Compound ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Synthetic Compounds ◽  
X Ray

AbstractHydrothermal synthesis produced the new compound SrCo2(AsO4)(AsO3OH)(OH)(H2O). The compound belongs to the tsumcorite group (natural and synthetic compounds with the general formula M(1)M(2)2(XO4)2(H2O,OH)2; M(1)1+,2+,3+ = Na, K, Rb, Ag, NH4, Ca, Pb, Bi, Tl; M(2)2+,3+ = Al, Mn3+, Fe3+, Co, Ni, Cu, Zn; and X5+,6+ = P, As, V, S, Se, Mo). It represents (1) the first Sr member, (2) the until now unknown [7]-coordination for the M(1) position, (3) the first proof of (partially) protonated arsenate groups in this group of compounds, and (4) a new structure variant.The crystal structure of the title compound was determined using single-crystal X-ray diffraction data. The compound is monoclinic, space group P21/a, with a = 9.139(2), b = 12.829(3), c = 7.522(2) Å, β = 114.33(3)°, V = 803.6(3) Å3, Z = 4 [wR2 = 0.065 for 3530 unique reflections]. The hydrogen atoms were located experimentally.

scholarly journals X-ray crystal structure of a malonate-semialdehyde dehydrogenase fromPseudomonassp. strain AAC

2017 ◽  
Vol 73 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Matthew Wilding ◽  
Colin Scott ◽  
Thomas S. Peat ◽  
Janet Newman
Keyword(s):  
Crystal Structure ◽  
Search Model ◽  
Molecular Replacement ◽  
X Rays ◽  
X Ray Diffraction ◽  
Acetyl Coa ◽  
Space Group ◽  
X Ray ◽  
Semialdehyde Dehydrogenase

The NAD-dependent malonate-semialdehyde dehydrogenase KES23460 fromPseudomonassp. strain AAC makes up half of a bicistronic operon responsible for β-alanine catabolism to produce acetyl-CoA. The KES23460 protein has been heterologously expressed, purified and used to generate crystals suitable for X-ray diffraction studies. The crystals belonged to space groupP212121and diffracted X-rays to beyond 3 Å resolution using the microfocus beamline of the Australian Synchrotron. The structure was solved using molecular replacement, with a monomer from PDB entry 4zz7 as the search model.

scholarly journals Synchrotron Nano-Diffraction Study of Thermally Treated Asbestos Tremolite from Val d’Ala, Turin (Italy)

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 311 ◽  
Author(s):  
Carlotta Giacobbe ◽  
Jonathan Wright ◽  
Dario Di Giuseppe ◽  
Alessandro Zoboli ◽  
Mauro Zapparoli ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Risk Management ◽  
Structure Analysis ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adverse Health Effects ◽  
Nano Crystalline ◽  
Original Fibre

Nowadays, due to the adverse health effects associated with exposure to asbestos, its removal and thermal inertization has become one of the most promising ways for reducing waste risk management. Despite all the advances in structure analysis of fibers and characterization, some problems still remain that are very hard to solve. One challenge is the structure analysis of natural micro- and nano-crystalline samples, which do not form crystals large enough for single-crystal X-ray diffraction (SC-XRD), and their analysis is often hampered by reflection overlap and the coexistence of multiple fibres linked together. In this paper, we have used nano-focused synchrotron X-rays to refine the crystal structure of a micrometric tremolite fibres from Val d’Ala, Turin (Italy) after various heat treatment. The structure of the original fibre and after heating to 800 °C show minor differences, while the fibre that was heated at 1000 °C is recrystallized into pyroxene phases and cristobalite.

Studies Directed Towards the Total Synthesis of Anticapsin. X-Ray Crystal-Structure of (1RS,2SR,4RS,5RS,6SR)-5-Hydroxy-2-phthalimido-1-trimethylsilyloxy-bicyclo[2.2.2]octane-2,6-carbolactone

1990 ◽  
Vol 43 (11) ◽  
pp. 1827 ◽  
Author(s):  
MJ Crossley ◽  
TW Hambley ◽  
AW Stamford
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Total Synthesis ◽  
Synthetic Approach ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography ◽  
Relative Stereochemistry ◽  
Atomic Parameters

The relative stereochemistry of methyl 2-phthalimido-1- trimethylsilyloxybicyclo[2.2.2]oct-5-ene-2-carboxylate (9) and its 5,6-epoxide (10), intermediates in a synthetic approach to the amino acid antibiotic anticapsin, were established by the TiCl4-mediated cyclization of (10) to the carbolactone (12); the structure of which was proved by single-crystal X-ray crystallography. Full-matrix least- squares refinement of all atomic parameters with individual isotropic thermal parameters for the hydrogen atoms by using 1446 reflections converged at R 0.036. Crystals of (12) are monoclinic, P21/c, a 12.342(3), b 12.239(2), c 13.405(3) Ǻ, β 99.34(2)°, Z 4.

Benzo-18-krone-6 -Acetonitril (1/2): Kristallisation und Tieftemperatur- Röntgenstrukturanalyse / Benzo-18 -crown-6 -Acetonitrile (1/2): Crystallization and Low-Temperature X-Ray Analysis

1998 ◽  
Vol 53 (12) ◽  
pp. 1528-1530 ◽  
Author(s):  
Karna Wijaya ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Data Collection ◽  
Single Crystals ◽  
Title Complex ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Space Group ◽  
X Ray ◽  
Mecn Solution

Abstract Benzo-18 -crown-6 -Acetonitrile (1/2), Crystal Structure Single crystals of the title complex resulted fortuitously during an attempt to co-crystallise MeN(SO2Me)2 with benzo-18-crown-6 from an MeCN solution at -30 °C. The crystal structure has been determined via data collection at -100 °C (monoclinic, space group P21/n, Z = 4). The nitrile molecules are located with their me­ thyl groups above and below the plane of the 18-membered crown ring, the Me hydrogen atoms being rotationally disordered about the MeCN axes; C(methyl)···O(crown) distances range from 309.4(3) to 384.9(3) pm.

Crystal structure of 2,3-Dichloro-5,8-dihydroxynaphtho-1,4-quinone

1978 ◽  
Vol 31 (3) ◽  
pp. 555 ◽  
Author(s):  
GI Feutrill ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Benzene Ring ◽  
Title Compound ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
The One ◽  
Least Squares Techniques

The crystal structure of the title compound has been determined at 295 K by single-crystal X-ray diffraction methods and refined by least- squares techniques to a residual of 0.049 for 1046 'observed' reflections. Crystals are monoclinic, P21/c, a 11.584(6), b 5.449(7), c 15.273(8) Ǻ, β 92.44(4)°, Z4. The pair of quinol hydrogen atoms are both located on the one benzene ring as the title indicates.

scholarly journals Dynamics of Water in Crystal Hydrates

1967 ◽  
Vol 22 (9) ◽  
pp. 1440-1451 ◽  
Author(s):  
Ingo Berthold ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Dynamical Behaviour ◽  
Water Molecules ◽  
Intensity Data ◽  
Two Dimensional ◽  
Fourier Synthesis ◽  
Hydrogen Atoms ◽  
X Ray ◽  
H Nmr

The crystal structure of Na2S2O6·2 H2O has been refined by means of single crystal X-ray intensity data. The structure of the isotypic Li2S2O6·2 H20 was also determined by single crystal studies. Two dimensional differential FOURIER synthesis revealed the approximate positions of the hydrogen atoms. From 1H-NMR investigations, the crystal structure, and information gained by IR spectroscopy the complete atomic arrangement in these two substances was obtained. The influence of the dynamical behaviour of the water molecules is taken into account in determining the hydrogen positions.

Crystal structure analysis of molecular dynamics using synchrotron X-rays

CrystEngComm ◽  
2015 ◽  
Vol 17 (46) ◽  
pp. 8786-8795 ◽  
Author(s):  
Manabu Hoshino ◽  
Shin-ichi Adachi ◽  
Shin-ya Koshihara
Keyword(s):  
Crystal Structure ◽  
Molecular Dynamics ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
X Rays ◽  
X Ray ◽  
X Ray Crystallography

X-ray crystallography using synchrotron X-rays enables observation of molecular dynamics in a crystal.

The Influence of Emulsifiers on the Crystal Properties of Tristearin and Trilaurin

1988 ◽  
Vol 3 (1) ◽  
pp. 19-22 ◽  
Author(s):  
J. Schlichter ◽  
I. Mayer ◽  
S. Sarig ◽  
N. Garti
Keyword(s):  
Crystal Structure ◽  
Melting Point ◽  
Diffraction Method ◽  
The Other ◽  
Sorbitan Monostearate ◽  
X Ray Diffraction ◽  
Sorbitan Monolaurate ◽  
X Ray ◽  
Crystal Properties ◽  
Long Chain

AbstractThe effect of solid emulsifiers, added at the level of 10%, on the lattice parameters of tristearin and trilaurin, has been studied by powder X-ray diffraction method. The presence of sorbitan monostearate and glycerol-l-stearate affects slightly the lattice constant a in tristearin; on the other hand, although sorbitan monostearate causes an increase in a of trilaurin, glycerol-l-stearate does not. The presence of sorbitan monolaurate and glycerol-l-laurate affect a of trilaurin similarly to the long chain emulsifiers.A correlation between the effect on a and the increase in melting point has been found.The presence of the emulsifier does not alter drastically the lattice dimensions of the fat. The slight dissimilarity in crystal structure between tristearin and trilaurin is confirmed by the diverse effects of the emulsifiers on the internal structure of the fat.

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