Separation of Orientational Disorder in the X-Ray Analysis of the Kinetically Stabilized 2-Silanaphthalene

2000 ◽  
Vol 73 (9) ◽  
pp. 2157-2158 ◽  
Author(s):  
Keiji Wakita ◽  
Norihiro Tokitoh ◽  
Renji Okazaki
Keyword(s):  
Orientational Disorder ◽  
X Ray

scholarly journals Crystallographic features of ammonium fluoroelpasolites: dynamic orientational disorder in crystals of (NH4)3HfF7 and (NH4)3Ti(O2)F5

2017 ◽  
Vol 73 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Anatoly A. Udovenko ◽  
Alexander A. Karabtsov ◽  
Natalia M. Laptash
Keyword(s):  
Single Crystal ◽  
Electron Density ◽  
Diffraction Data ◽  
Central Atom ◽  
X Ray Diffraction ◽  
Dynamic Nature ◽  
Orientational Disorder ◽  
High Quality ◽  
Structural Units ◽  
X Ray

A classical elpasolite-type structure is considered with respect to dynamically disordered ammonium fluoro-(oxofluoro-)metallates. Single-crystal X-ray diffraction data from high quality (NH4)3HfF7 and (NH4)3Ti(O2)F5 samples enabled the refinement of the ligand and cationic positions in the cubic Fm \bar 3 m (Z = 4) structure. Electron-density atomic profiles show that the ligand atoms are distributed in a mixed (split) position instead of 24e. One of the ammonium groups is disordered near 8c so that its central atom (N1) forms a tetrahedron with vertexes in 32f. However, a center of another group (N2) remains in the 4b site, whereas its H atoms (H2) occupy the 96k positions instead of 24e and, together with the H3 atom in the 32f position, they form eight spatial orientations of the ammonium group. It is a common feature of all ammonium fluoroelpasolites with orientational disorder of structural units of a dynamic nature.

Structure of Cerebrosides. II. Small Angle X-Ray Diffraction Study of Cerasine

1979 ◽  
Vol 34 (12) ◽  
pp. 1121-1124 ◽  
Author(s):  
R. Hosemann ◽  
J. Loboda-Čačković ◽  
H. Čačković ◽  
S. Fernandez-Bermúdez ◽  
F. J. Baltá-Calleja
Keyword(s):  
Molecular Weight ◽  
Fatty Acid ◽  
Hydrogen Atom ◽  
Low Temperature ◽  
Hydroxyl Group ◽  
X Ray Diffraction ◽  
Orientational Disorder ◽  
X Ray ◽  
Long Period ◽  
Lattice Planes

Cerasine having a molecular weight of 800 differs chemically from phrenosine only in the hydroxyl group attached to the fatty acid tail which is replaced by a hydrogen atom. Nevertheless, remarkable differences between both cerebrosides are detected in the lamellae periodicities. In the range of 23 - 66 °C just one single (instead of two) structure with a similar subcell to the triclinic one component of phrenosine is detected. Between 66 and 87 °C three new components (instead of one in phrenosine) appear. Two of the structures are similar to the two phrenosine-components at low temperature and the tilt angles of their chains with respect to the basal planes can explain the stabilizing capacity of the 201 and 301 netplanes of the paraffin-like subcells respectively. These lattice planes are parallely aligned to the surfaces of the lamellae. The long period of 58 Å of component II cannot be explained in such a wav. This period persits upto 105 °C and coexists from 87 °C with a new component showing a 40 Å-periodicity, which cannot either be explained in the above manner. Paracrystalline distortions of the arrangement of the bilayers can be justified by orientational disorder of the galactose heads.

Orientational Disorder of (trans)-4-Chloro-4′-nitrostilbene: A Detailed Analysis by Single Crystal X-ray Diffraction

2010 ◽  
Vol 10 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Norwid-Rasmus Behrnd ◽  
Gaël Labat ◽  
Paloth Venugopalan ◽  
Jürg Hulliger ◽  
Hans-Beat Bürgi
Keyword(s):  
Single Crystal ◽  
Detailed Analysis ◽  
X Ray Diffraction ◽  
Orientational Disorder ◽  
X Ray

scholarly journals Die Kristallstruktur des Cyano-Elpasoliths [N(CH3)4]2CsFe(CN)6 / The Crystal Structure of the Cyano Elpasolite [N(CH3)4]2CsFe(CN)6

1982 ◽  
Vol 37 (12) ◽  
pp. 1534-1539 ◽  
Author(s):  
D. Babel
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
The Other ◽  
Methyl Groups ◽  
Orientational Disorder ◽  
Space Group ◽  
X Ray ◽  
Ray Methods ◽  
The Ideal

The crystal structure of the cubic compound [N(CH3)4]2CsFe(CN)6 was determined by X-ray methods: a = 2527.4(6) pm, space group Fd3c, Z = 32, Rg = 0.028 (260 independent single crystal reflections). The resulting distances within the practically undistorted Fe (CN)63- - octahedron are Fe-C = 193.4(6) and C-N = 115.7(7) pm. Compared to the ideal elpasolite structure of space group Fm3m, Z = 4, the octahedra are rotated by 7.4° through their 3 axis. This is discussed as caused by steric requirements of the tetramethylammonium groups (N-C = 148.4(10) and 149.1(38) pm, resp.). Three quarters of them, of which also the hydrogen positions could be located, are well oriented. The remaining quarter shows orientational disorder to approach similar contact distances as the other N(CH3)4+ ion exhibits between the methyl groups and the nitrogen ends of the anions

Single-Crystal X-Ray Diffraction Study of the Room Temperature Structure and Orientational Disorder of C 70

1994 ◽  
Vol 27 (5) ◽  
pp. 359-364 ◽  
Author(s):  
E Blanc ◽  
H.-B Bürgi ◽  
R Restori ◽  
D Schwarzenbach ◽  
P Stellberg ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
Room Temperature ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
Orientational Disorder ◽  
X Ray

scholarly journals X-Ray Study of Orientational Disorder in Crystals

1982 ◽  
Vol 24 (2) ◽  
pp. 122-131
Author(s):  
Yasuhiro SHINNAKA
Keyword(s):  
Orientational Disorder ◽  
X Ray

X-Ray Study of Orientational Disorder in Cubic RbNO3

1981 ◽  
Vol 50 (6) ◽  
pp. 2091-2094 ◽  
Author(s):  
Yasuhiro Shinnaka ◽  
Seishi Yamamoto
Keyword(s):  
Orientational Disorder ◽  
X Ray
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