The Crystal Structure of Rubber Hydrochloride

1943 ◽  
Vol 16 (4) ◽  
pp. 848-856
Author(s):  
C. W. Bunn ◽  
E. V. Garner
Keyword(s):  
Crystal Structure ◽  
Physical Properties ◽  
Carbon Chain ◽  
Point Of View ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Compounds ◽  
Ray Methods ◽  
Temperature Melting

Abstract “Rubber hydrochloride”, the crystalline substances made by addition of hydrogen chloride to rubber, is of interest for two reasons. First, the periodicity along the fibre axis of drawn specimens indicates that the carbon chain has not the simple plane zigzag form found in paraffin hydrocarbons, but is somewhat shortened by folding. There is similar evidence that several other chain polymers also have folded chains; the elucidation of the geometry of such molecules would form a useful contribution to our knowledge of the stereochemistry of carbon compounds in general and chain polymers in particular. Rubber hydrochloride appeared to be a suitable substance for crystallographic investigation from this point of view: it gives a well-defined x-ray diffraction pattern. Moreover, a prediction of the chain form has been made on the basis of a knowledge of the periodicity and the use of a hypothesis which has been called the principle of staggered bonds. The determination of the structure by x-ray methods forms the first test of the validity and usefulness of this hypothesis. Secondly, rubber hydrochloride is interesting on account of its physical properties. Unlike rubber itself, it is crystalline at room temperature, “melting” at about 115° C. The present work on its crystal structure forms part of a program of research being carried out in this laboratory, and is a contribution to the attempt to understand the physical properties of chain polymers in terms of molecular structure.

X-Ray Crystal Structure Determination of Some Sodium Anthraquinone Sulfonate Derivatives

1993 ◽  
Vol 46 (10) ◽  
pp. 1595 ◽  
Author(s):  
e Gamag ◽  
e Gamag ◽  
BM Peake ◽  
BM Peake ◽  
J Simpson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
X Ray Diffraction ◽  
Molecular Mechanics Calculations ◽  
X Ray ◽  
Photochemical Behaviour ◽  
Sufficient Magnitude ◽  
Ray Methods

The crystal structures of sodium 9,10-dioxo-9,10-dihydroanthracene-2-sulfonate hydrate (1) and sodium 9,10-dioxo-9,10-dihydroanthracene-1,5-disulfonate trihydrate (2) have been determined by single-crystal X-ray diffraction at 253 K and refined to R 0.03 for (1) (1535 reflections) and R 0.04 for (2) (1409 reflections). Crystals of (1) are monoclinic, P21, a 17.395(5), b 6.625(2), c 5.537(1)Ǻ, β 91.87(2)°, Z 2, and those of (2) are orthorhombic, Pnma, a 11.332(4), b 20.048(5), c 7.634(3)Ǻ, Z 4. The results of molecular mechanics calculations on these two molecules were in general agreement with those determined by X-ray methods. The effect of sulfonate substitution in the 1-position compared with that in the 2-position include a small lengthening of the C-S bond and a displacement of the sulfur and quinone oxygen atoms to opposite sides of the plane of the substituted aromatic ring. However, these differences do not appear to be of sufficient magnitude to account for the much greater differences in the electrochemical and photochemical behaviour of these two classes of anthraquinone sulfonate derivatives.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

scholarly journals Magnetically Oriented Powder Crystal to Indexing and Structure Determination

2014 ◽  
Vol 70 (a1) ◽  
pp. C1560-C1560
Author(s):  
Fumiko Kimura ◽  
Wataru Oshima ◽  
Hiroko Matsumoto ◽  
Hidehiro Uekusa ◽  
Kazuaki Aburaya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Powder Diffraction ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Lattice Parameters

In pharmaceutical sciences, the crystal structure is of primary importance because it influences drug efficacy. Due to difficulties of growing a large single crystal suitable for the single crystal X-ray diffraction analysis, powder diffraction method is widely used. In powder method, two-dimensional diffraction information is projected onto one dimension, which impairs the accuracy of the resulting crystal structure. To overcome this problem, we recently proposed a novel method of fabricating a magnetically oriented microcrystal array (MOMA), a composite in which microcrystals are aligned three-dimensionally in a polymer matrix. The X-ray diffraction of the MOMA is equivalent to that of the corresponding large single crystal, enabling the determination of the crystal lattice parameters and crystal structure of the embedded microcrytals.[1-3] Because we make use of the diamagnetic anisotropy of crystal, those crystals that exhibit small magnetic anisotropy do not take sufficient three-dimensional alignment. However, even for these crystals that only align uniaxially, the determination of the crystal lattice parameters can be easily made compared with the determination by powder diffraction pattern. Once these parameters are determined, crystal structure can be determined by X-ray powder diffraction method. In this paper, we demonstrate possibility of the MOMA method to assist the structure analysis through X-ray powder and single crystal diffraction methods. We applied the MOMA method to various microcrystalline powders including L-alanine, 1,3,5-triphenyl benzene, and cellobiose. The obtained MOMAs exhibited well-resolved diffraction spots, and we succeeded in determination of the crystal lattice parameters and crystal structure analysis.

scholarly journals Rubidium tetrafluoridobromate(III): redetermination of the crystal structure from single-crystal X-ray diffraction data

IUCrData ◽  
2019 ◽  
Vol 4 (11) ◽  
Author(s):  
Artem V. Malin ◽  
Sergei I. Ivlev ◽  
Roman V. Ostvald ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Atomic Coordinates

Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598].

Effects of Electron Beam on Structure and Physical Properties of Natural Colorless Topaz

2015 ◽  
Vol 1125 ◽  
pp. 60-63
Author(s):  
Chutharat Paikaew ◽  
Juthamas Inthanont ◽  
Adisak Punyanut ◽  
Ekachai Hoonnivathana ◽  
Pichet Limsuwan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Beam ◽  
Physical Properties ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spin Resonance ◽  
Function Group ◽  
And Function ◽  
Beam Dose

The purpose of this research was to investigate physical properties, configuration and color of topaz. Topazes were irradiated with electron beam linear accelerator at different dose from 40 to 180 MGy. The color of topaz was analyzed by UV-vis and it was shown that the color of topaz was becoming strong color with increased electron beam dose. Crystal structure and function group of topaz were characterized by X- ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The results showed that the topaz has orthorhombic structure and no other crystalline. After irradiated, topaz released OH indicating higher crystallinity of topaz and this was confirmed with the results of electron spin resonance (ESR). Electron beam dose response of topaz was investigated. ESR results showed that the Al3+ ion was substituted in Si4+ site and Ti3+ impurity in Al4+ site and this result corresponds to the results of FTIR. The experiment result indicated that electron beam could be making defect on crystal structure and color enhancement of topaz.

Determination of the Crystal Structure and Redefinition of Tsugaruite, Pb28As15S50Cl, the First Lead-Arsenic Chloro-Sulfosalt

2020 ◽  
Author(s):  
Cristian Biagioni ◽  
Luca Bindi ◽  
Koichi Momma ◽  
Ritsuro Miyawaki ◽  
Yoshitaka Matsushita ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Specific Position ◽  
Actual Classification ◽  
Aomori Prefecture

Abstract Tsugaruite was originally defined as a lead-arsenic sulfosalt from the Yunosawa mine, Aomori Prefecture, Japan. Until recently its crystal structure remained unsolved and its actual classification in the sulfosalt realm was unknown. Here the refinement of the crystal structure of tsugaruite using single-crystal X-ray diffraction data is reported. The mineral is orthorhombic, space group P2nn, with unit-cell parameters a = 8.0774(10), b = 15.1772(16), c = 38.129(4) Å, V = 4674.3(9) Å3, in agreement with previous studies. The solution of the crystal structure of this mineral revealed Cl occupying a specific position. Chlorine was thus sought and found using the electron microprobe; the average of six spot analyses gave (in wt.%): Pb 68.04, As 12.83, S 18.29, Cl 0.63, total 99.80. The empirical formula, calculated on the basis of Pb + As = 43 atoms per formula unit, is Pb28.26As14.74S49.08Cl1.52. Tsugaruite is an N = 4 plesiotypic derivative of the homologous series of Pb-Sb chloro-sulfosalts having the general formula Pb(2+2N)(Sb,Pb)(2+2N)S(2+2N)(S,Cl)(4+2N)ClN. It has a Cl/(Cl + S) atomic ratio close to that of other known Pb-Sb chloro-sulfosalts (pillaite, pellouxite) and slightly higher than that of dadsonite.

Structure determination of fatty acid ester biofuels via in situ cryocrystallisation and single crystal X-ray diffraction

CrystEngComm ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Siriyara Jagannatha Prathapa ◽  
Cara Slabbert ◽  
Manuel A. Fernandes ◽  
Andreas Lemmerer
Keyword(s):  
Crystal Structure ◽  
Fatty Acid ◽  
Fatty Acid Ester ◽  
Structure Determination ◽  
Homologous Series ◽  
Methyl Esters ◽  
X Ray Diffraction ◽  
X Ray

In situ cryocrystallisation enabled the crystal structure determination of a homologous series of low-melting n-alkyl methyl esters Cn−1H2n+1CO2CH3.

Detection Confirmation and Determination of Trace Amounts of Selenium by X-Ray Methods

1963 ◽  
Vol 7 ◽  
pp. 542-554
Author(s):  
Frank L. Chan
Keyword(s):  
Matrix Effects ◽  
Hexagonal Structure ◽  
Elemental Selenium ◽  
X Ray Diffraction ◽  
X Ray ◽  
Yellow Color ◽  
The Matrix ◽  
Ray Methods ◽  
Tetravalent State

AbstractRecently, interest in the determination of selenium in trace amounts has been greatly intensified because of the nutritional aspects of this element. It has been reported that selenium in the amount of 13 μg in the form of sodium selenite in 100 g of feed has an effect similar to that of vitamin E. In the field of semiconductors, the detection and determination of trace amounts of selenium in arsenic, antimony, and small single crystals of solid solution of cadmium selenide and sulfide are of considerable importance in semiconductor performance.In the Aerospace Research Laboratories, 4,5 diamino-6-tbiopyi-imidine has been successfully adopted as a reagent for the spectrophotometric determination of selenium. The reaction of 4,5 diamino-6-thiopyrimidine and tetxavalent selenium produces a yellow color with the formation of elemental selenium. It is possible to determine elemental selenium by collecting it in a thin layer. The selenium deposited in this layer may then be determined by an X-ray fluorescence method. A procedure of this nature has the advantage of eliminating the matrix effects commonly encountered in X-ray fluorescence. Furthermore, the slow generation of selenium affords a convenient means of detection and confirmation of this element by the use of X-ray diffraction procedures. By this technique selenium is first converted to its tetravalent state and is then reacted with 4,5 diamino-6-thiopyrimidine. On standing, the selenium is reduced to a red precipitate of elemental selenium which can be dissolved in carbon disulfide. Finally, the selenium can be converted into its hexagonal structure by annealing at 205-207°C.

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