The Structure of Polyisoprenes. II. The Structure of β-Gutta-Percha

1945 ◽  
Vol 18 (2) ◽  
pp. 280-283
Author(s):  
G. A. Jeffrey
Keyword(s):  
Molecular Structure ◽  
Double Bond ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Interatomic Distances ◽  
Methyl Group ◽  
X Ray ◽  
Gutta Percha ◽  
Qualitative Estimate

Abstract The x-ray diffraction data at present available from β-gutta-percha are shown to be insufficient to distinguish fine details of molecular structure. Since a qualitative estimate of the intensities on the fibre diagram can be adequately satisfied by a model having normal interatomic distances and valency angles, no evidence exists for the improbable distortion of the methyl group out of the plane of the double bond previously ascribed to the molecule.

Structure cristalline et moléculaire d'un composé tricyclique contenant le cycle à dix chaînons dioxo diaza diphosphécine

1992 ◽  
Vol 70 (3) ◽  
pp. 809-816 ◽  
Author(s):  
Brigitte Duthu ◽  
Karim El Abed ◽  
Douraid Houalla ◽  
Robert Wolf ◽  
Joël Jaud
Keyword(s):  
Molecular Structure ◽  
Comparative Analysis ◽  
Double Bond ◽  
Mass Spectroscopy ◽  
Crystal And Molecular Structure ◽  
Accurate Information ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Parameters ◽  
C Nmr

The sulfuration of the tricyclic organophosphorous dimer 2 leads easily to the dithiotricyclic derivative 3, which has been characterized by 31P, 1H, and 13C NMR, elemental analysis, and mass spectroscopy. Its crystal and molecular structure has been established by X-ray diffraction and compared to that of 2, which was previously determined. The comparative analysis of X-ray diffraction and NMR parameters gives accurate information about the molecular structure of both compounds. A numerical value of the anistropy cone of the P=S double bond is proposed. Keywords: phosphecine, NMR, X-ray, tricycle.

Crystal and Molecular Structure of Dithiocyanato(triphenylarsine)mercury(II)

1975 ◽  
Vol 53 (22) ◽  
pp. 3383-3387 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp ◽  
Roland Rivest
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Coordination Number ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Method

The crystal and molecular structure of dithiocyanato(triphenylarsine)mercury(II) has been determined from X-ray diffraction data. The crystals are monoclinic, space group P21/c, with a = 10.290(7), b = 21.199(23), c = 10.719(7) Å, β = 112.00(2)°, and Z = 4. The structure has been solved by the heavy-atom method and refined by block-diagonal least-squares calculations. The agreement factor R obtained for 2607 'observed' reflections is 0.030. The crystal consists of single molecules. The 'characteristic' coordination number of mercury is three, with two sulfur and one arsenic atoms at the apexes of a triangle. The nitrogen atoms of the thiocyanate groups are at 2.67 and 2.74 Å from the adjoining mercury atoms and therefore link the different molecules together.

The crystal and molecular structure of ovalene: some three-dimensional refinements

1973 ◽  
Vol 137 (2-3) ◽  
Author(s):  
R. G. Hazell ◽  
G. S. Pawley
Keyword(s):  
Molecular Structure ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray

AbstractThree-dimensional x-ray diffraction data have been taken from ovalene, C

The crystal and molecular structure of a 1:1 complex of 5-bromouridine and dimethylsulphoxide

1968 ◽  
Vol 302 (1469) ◽  
pp. 225-236 ◽  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Temperature

A complex consisting of one molecule of 5-bromouridine ( BUR ) and one molecule of di­methylsulphoxide ( DMSO ) has been prepared in the form of monoclinic crystals. The unit cell parameters are as follows, a = 13⋅65 ± 0⋅01, b = 4.820 ± 0⋅005, c = 12⋅09 ± 0⋅01 Å, β = 91⋅8 ± 0.1°, space group P 2 1 . X-ray diffraction data ( ⋋ = 1⋅5418 Å) for 1389 independent reflexions were collected and the structure was determined from Patterson syntheses which gave the coordinates of the bromine and sulphur atoms. Fourier syntheses followed by least-squares refinement (including anisotropic temperature parameters) reduced the agreement index R to 0⋅067. The bond lengths and angles for each molecule are given, and it is shown that hydrogen bonds are formed between the oxygen atom of the DMSO molecule and the 03' and 05' of the BUR molecules. A comparison is made between the conformation of the BUR molecule in this complex and that of the same molecule in two other structures.

Molekül-und Elektronenstruktur des Thioheteroanions [S2 WS2CoS2WS2]2- / Molecular and Electronic Structure of the Thiohetero Anion [S2WS2CoS2WS2]2-

1978 ◽  
Vol 33 (9) ◽  
pp. 978-982 ◽  
Author(s):  
A. Müller ◽  
N. Mohan ◽  
H. Bögge
Keyword(s):  
Molecular Structure ◽  
Electronic Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Complex Anion ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Data Space ◽  
Molecular And Electronic Structure

Abstract The crystal and molecular structure of [(C6H5)4P]2[Co(WS4)2] was determined from single crystal X-ray diffraction data (space group P21/c with a = 18.542(4), b = 15.443(2), c= 18.713(2) Å, β= 108.73(1)°, Z = 4). In the complex anion Co is coordinated by two bidentate chelating WS42- anions, with a nearly tetrahedral surrounding of Co. The bond lengths in the planar metal sulfur ring CoS2W are Co-S = 2.26 Å and W-S = 2.22 Å, while the terminal W-S bonds are 2.14 Å.

scholarly journals Synthesis, Molecular Structure from the X-ray Diffraction Data of the Powder (1E,1'E)-1,1'-(1,4-Phenylene)Bis(N-(Adamantan-1-yl)methanimine)

2021 ◽  
pp. 1066-1076
Author(s):  
Shukkur A. Hamed
Keyword(s):  
Molecular Structure ◽  
Schiff Base ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Title Compound ◽  
Good Yield ◽  
Chair Conformation ◽  
Parallel Tempering ◽  
X Ray Diffraction ◽  
X Ray

The title compound was synthesized by 2:1 condensation between adamantan-1-ylamine and benzene-1,4- dicarbaldehyde in n-BuOH and produced a good yield 87% of new bis Schiff base. The compound skeleton was affirmed by FTIR, 1H NMR, LC-MS, and X-ray powder diffraction. The structure was solved by a parallel tempering process and refined by using Rietveld refinement. Two adamantan-1-ylimino groups are connected in the anti-positions to the planar central 1,4-dimethylbenzene group. All rings of the adamantyl group possess normal chair conformation.

Further X-Ray Studies of Gutta-Percha and Balata

1931 ◽  
Vol 4 (3) ◽  
pp. 445-449
Author(s):  
Charles W. Stillwell ◽  
George L. Clark
Keyword(s):  
Diffraction Pattern ◽  
Diffraction Data ◽  
Fundamental Difference ◽  
Practical Significance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beta Form ◽  
Gutta Percha ◽  
Diffraction Patterns ◽  
Crystalline Forms

Abstract New x-ray diffraction data for gutta-percha and balata are given and considered in the light of von Susich's recent conclusion that these substances are identical and exist in two crystalline forms. The data also support the assumption that gutta-percha is a mixture of balata and another crystalline constituent, an assumption that is in some respects preferable to that of von Susich. Although the relation between gutta-percha and balata has been established and there may be no ultimate difference between them, it is pointed out that the majority of specimens examined of material classified commercially as balata produce a diffraction pattern different from that of gutta-percha, a fact of practical significance. THERE has been considerable disagreement as to the significance of x-ray diffraction data for gutta-percha and balata as reported by different investigators. The main point at issue has been the fundamental difference between gutta-percha and balata. Clark (1) and Hauser (2) have obtained different diffraction patterns for the two when unstretched, while Hauser has found them to be the same when stretched. Von Susich (3) has recently done much to clarify the problem. He reaches the conclusion, as a result of x-ray diffraction data, that gutta-percha and balata are identical, and that the substance exists in two different crystalline modifications, the alpha form being stable below about 60° C. and changing to the beta form when heated above this temperature. Of course, this at once explains Hauser's results, since the specimens were doubtless heated above 60° C. when stretched and would then show the beta pattern.

3-Ethoxycarbonyl-2,2,5,5-tetramethyl-1H-2,5-dihydropyrrol-1-yloxyl

2000 ◽  
Vol 57 (1) ◽  
pp. o85-o86 ◽  
Author(s):  
Jarmila Duskova ◽  
Jiri Labsky ◽  
Jindrich Hasek ◽  
Ivana Cisarova
Keyword(s):  
Molecular Structure ◽  
Diffraction Data ◽  
Title Compound ◽  
Main Part ◽  
Crystal And Molecular Structure ◽  
Mirror Plane ◽  
X Ray Diffraction ◽  
Special Position ◽  
X Ray ◽  
Compound C

The crystal and molecular structure of the title compound, C11H18NO3, has been determined from X-ray diffraction data. The compound crystallizes in the centrosymmetric space groupPnma. The main part of the molecule lies at a special position on the mirror plane.

Crystal structure of cesium methylsulfonate, CsCH3SO3

1967 ◽  
Vol 45 (12) ◽  
pp. 1385-1390 ◽  
Author(s):  
J. K. Brandon ◽  
I. D. Brown
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Barium Sulfate ◽  
Three Dimensional ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Methyl Group ◽  
Space Group ◽  
X Ray ◽  
Cesium Ion

Cesium methylsulfonate, CsCH3SO3, crystallizes in space group Pnma with a = 9.526, b = 6.264, and c = 8.692 Å. Three-dimensional X-ray diffraction data have been collected photographically and refined to give a weighted agreement index (R) of 0.12. The structure is related to, but is not identical with, that of the isoelectronic compound barium sulfate. The CH3SO3− ion has C3v symmetry within the accuracy of this analysis, with S—O = 1.47 ± 0.02, S—C = 1.85 ± 0.04 Å (corrected for thermal motion), O—S—O = 112 ± 1°, and O—S—C = 107 ± 2°. The cesium ion is surrounded by nine oxygen atoms (Cs—O between 3.12 and 3.35 Å) and one methyl group (Cs—C = 3.77 Å).

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