Structure and thermal expansion of sulfuric acid octahydrate

2012 ◽  
Vol 45 (6) ◽  
pp. 1198-1207 ◽  
Author(s):  
Helen E. Maynard-Casely ◽  
Helen E. A. Brand ◽  
Kia S. Wallwork
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Sulfuric Acid ◽  
Powder Diffraction ◽  
Unit Cell ◽  
Acid Solutions ◽  
X Ray ◽  
Structure Solution ◽  
Sulfuric Acid Solutions

Synchrotron X-ray powder diffraction has been used to structurally characterize crystallization products from 37.8 and 40.5 wt% aqueous sulfuric acid solutions. It is confirmed that, despite speculation in the literature, the structure that predominately crystallized from these solutions is sulfuric acid octahydrate (SAO). The existence of an uncharacterized phase is also noted. It was found that existing models proposed for the crystal structure of SAO did not satisfactorily fit to the data acquired here, and hence a new structure solution was sought. It is reported here that the structure of SAO is contained within a unit cell withI2 symmetry witha= 7.44247 (11),b= 7.4450 (1),c= 26.1168 (3) Å, β = 125.0428 (7)°,V= 1184.78 (3) Å3at 80 K. Data were collected at temperatures between 80 and 198 K, which enabled determination of the thermal expansion of SAO.

Simultaneous radiometric determination of uranium and thorium in sulfuric acid solutions

1972 ◽  
Vol 31 (6) ◽  
pp. 1425-1427 ◽  
Author(s):  
V. V. Anosov ◽  
N. I. Gavrilov ◽  
T. P. Smelkova
Keyword(s):  
Sulfuric Acid ◽  
Acid Solutions ◽  
Sulfuric Acid Solutions ◽  
Radiometric Determination

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.

Über neue monocyclische Acyloxyfluoroborane 2.2.6.6-Tetrafluoro-1.4-dialkyl-1.3.5-trioxa-1.6-diboracyclohexene: Darstellung, Molekül- und Kristallstruktur/ New Monocyclic Acyloxyfluoroboranes 2,2,6,6-Tetrafluoro-1,4-dialkyl-1,3,5-trioxa-2,6-diboracyclohexenes: Synthesis, Molecular and Crystal Structure

1983 ◽  
Vol 38 (5) ◽  
pp. 554-558 ◽  
Author(s):  
Herbert Binder ◽  
Walter Matheis ◽  
Hans-Jörg Deiseroth ◽  
Han Fu-Son
Keyword(s):  
Crystal Structure ◽  
Organic Acid ◽  
Structure Determination ◽  
Unit Cell ◽  
Ring Conformation ◽  
X Ray ◽  
Conformational Isomers ◽  
Ring Group ◽  
Acid Anhydrides

Abstract Acyloxyfluoroboranes Trimeric alkoxydifluoroboranes (F2BOR)3 (2) react with organic acid anhydrides by substitution of a ring group OR forming monocyclic acyloxyfluoroboranes of the type 2,2,6,6-tetrafluoro-l,4-dialkyl-l,3,5-trioxa-2,6-diboracyclohexene (3). The X-ray crystal structure determination of 3a shows two conformational isomers: two planar and two non-planar six-membered rings are present in the unit cell. The ring conformation is influenced by weak intermolecular H — F interactions.

The crystal structure and thermal expansion of the CCl4 adduct of Dianin's compound

1990 ◽  
Vol 68 (8) ◽  
pp. 1352-1356 ◽  
Author(s):  
Walter Abriel ◽  
André Du Bois ◽  
Marek Zakrzewski ◽  
Mary Anne White
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Dianin's Compound

The crystal structure of the title compound has been determined by single crystal X-ray diffraction data collected at 293 K, and refined to a final Rw of 0.057. The crystals are rhombohedral, space group [Formula: see text], with a = 27.134(8) Å, c = 10.933(2) Å, and Z = 18. The mole ratio of Dianin's compound (4-p-hydroxyphenyl-2,2,4-trimethylchroman) to CCl4 is 6:1. The guest molecules are disordered. X-ray powder diffraction was carried out in the temperature range from 10 to 300 K. From this, the thermal expansion coefficients for the a- and c-axes and the volume have been determined. Keywords: thermal expansion, crystal structure, clathrate.

A synergic approach of X-ray powder diffraction and Raman spectroscopy for crystal structure determination of 2,3-thienoimide capped oligothiophenes

2018 ◽  
Vol 20 (5) ◽  
pp. 3630-3636 ◽  
Author(s):  
C. Cappuccino ◽  
P. P. Mazzeo ◽  
T. Salzillo ◽  
E. Venuti ◽  
A. Giunchi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Powder Diffraction ◽  
Structure Determination ◽  
Molecular Conformation ◽  
Rapid Identification ◽  
Crystal Structure Determination ◽  
X Ray

This work presents a Raman based approach for the rapid identification of the molecular conformation in a series of new 2,3-thienoimide capped quaterthiophenes.

Crystal structure study of selected xanthine derivatives

2010 ◽  
Vol 43 (1) ◽  
pp. 163-167 ◽  
Author(s):  
W. Lasocha ◽  
B. Gaweł ◽  
A. Rafalska-Lasocha ◽  
M. Pawłowski ◽  
P. Talik ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Powder Diffraction ◽  
Structure Study ◽  
Asymmetric Unit ◽  
Pharmaceutical Samples ◽  
X Ray ◽  
Xanthine Derivatives ◽  
Structure Solution ◽  
Theophylline Derivatives

The crystal structures of two compounds belonging to a group of theophylline derivatives have been solved by X-ray powder diffraction methods. Despite the fact that these compounds seemed to be rather simple (23 atoms in an asymmetric unit), the preferred orientation and dominant zone problems created very serious obstacles in the investigations, even for the most modern powder diffraction methods. The crystal structure of the first compound, 8-phenylazoxanthine, C14H14N6O2, was finally solved from laboratory diffractometer data, while in the case of the second compound, 8-(3-bromobenzylidene)xanthine, C15H14N5O2Br, it was not possible to reliably index its diffraction pattern until data had been collected at the high-resolution powder diffractometer ID31 at the ESRF Grenoble. The serious problems encountered during anab initiocrystal structure solution from powder data of these pharmaceutical samples are described and discussed.

The crystal structure of trisodium hexachlororhodate (Na3RhCl6)

2018 ◽  
Vol 33 (1) ◽  
pp. 62-65
Author(s):  
Martin Etter
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Structure Type ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Commercially available trisodium hexachlororhodate (Na3RhCl6) was dehydrated and characterized by laboratory X-ray powder diffraction. The crystal structure is isostructural to the Na3CrCl6 structure type with space group P$\bar 31$c. Unit-cell parameters are a = 6.8116(1) Å, c = 11.9196(2) Å, V = 478.95(2) Å3, and Z = 2.

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