The X-Ray Crystal Structure and Packing of a Hexakis-adduct of C60: Temperature dependence of weak C?H?O interactions

1996 ◽  
Vol 79 (4) ◽  
pp. 1047-1058 ◽  
Author(s):  
Paul Seiler ◽  
Lyle Isaacs ◽  
Fran�ois Diederich
Keyword(s):  
Crystal Structure ◽  
Temperature Dependence ◽  
X Ray

scholarly journals Crystal Structure and Dielectric Property of Endohedral Lithium Fullerene

2014 ◽  
Vol 70 (a1) ◽  
pp. C195-C195
Author(s):  
Shinobu Aoyagi ◽  
Kunihisa Sugimoto ◽  
Hiroshi Okada ◽  
Norihisa Hoshino ◽  
Tomoyuki Akutagawa
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Dielectric Property ◽  
Low Temperature ◽  
Dielectric Permittivity ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Structure Analysis ◽  
X Ray ◽  
Dielectric Phase

Endohedral lithium fullerene Li+@C60 can have a dielectric polarization by the off-centered location of the Li+ cation inside the C60 cage. The x-ray structure analysis of the PF6– salt [Li@C60](PF6) revealed that the Li+ cation occupies two off-centered equivalent positions at 20 K and hence the crystal is non-polar [1]. The disordered structure at low temperature is explained by a static orientation disorder of polar Li+@C60 cations and/or a dynamic tunneling of the Li+ cation inside the C60 cage. The Li+ tunneling would be suppressed by an intermolecular interaction at lower temperature and a dielectric phase transition might be induced. We reveal the dielectric property and crystal structure of [Li@C60](PF6) below 20 K in this study. The temperature dependence of the dielectric permittivity was measured for the single crystal down to 9 K. The dielectric permittivity increases with decreasing temperature according to the Curie-Weiss law. Such a behavior was also observed in H2O@C60 crystal but not in empty C60 crystal [2]. No dielectric phase transition was observed in H2O@C60 down to 8 K. In contrast, a dielectric anomaly suggesting a phase transition was observed in [Li@C60](PF6) around 18 K. The single-crystal x-ray diffraction experiment below 20 K was also performed at SPring-8 BL02B1. The crystal has a cubic structure at 20 K [1]. The temperature dependence of the cubic lattice constant shows no anomaly around 18 K. However, diffraction peaks that are forbidden for the given structure appear below 18 K. Thus the crystal symmetry is lowered by the dielectric phase transition. We present the result of the crystal structure analysis of the newly discovered low-temperature phase.

Ferromagnetic Intermolecular Interaction and Crystal Structure of α-Nitronyl Nitroxide

1989 ◽  
Vol 173 ◽  
Author(s):  
Kunio Awaga ◽  
Tamotsu Inabe ◽  
Yusei Maruyama
Keyword(s):  
Crystal Structure ◽  
Temperature Dependence ◽  
Intermolecular Interaction ◽  
Magnetic Coupling ◽  
Two Dimensional ◽  
Nitronyl Nitroxide ◽  
Magnetic Susceptibilities ◽  
X Ray ◽  
Nitronyl Nitroxides ◽  
Coulomb Attraction

ABSTRACTThe temperature dependence of the magnetic susceptibilities for several ±-nitronyl nitroxides have been measured. It is found that the intermolecular magnetic coupling in these radical crystals changes from antiferromagnetic to ferromagnetic depending on the substituents at ±-position. X-Ray crystal analysis and MO calculation have been carried out on the ferromagnetic ±-nitronyl nitroxide, 2-(4-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy 3-oxide, revealing a two-dimensional ferromagnetic network linked by the Nδ+...0δ− Coulomb attraction.

Temperature dependence of crystal structure of NaK0.72(NH4)0.28(+)-C4H4O6.4H2O in the paraelectric phase

1996 ◽  
Vol 52 (6) ◽  
pp. 976-981 ◽  
Author(s):  
E. Suzuki ◽  
H. Kabasawa ◽  
T. Honma ◽  
R. Nozaki ◽  
Y. Shiozaki
Keyword(s):  
Crystal Structure ◽  
Structural Change ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Paraelectric Phase ◽  
The Other ◽  
Carboxylate Anion ◽  
Water Molecules ◽  
Crystal Data ◽  
X Ray

The crystal structures of the ferroelectric NaK0.72 (NH4)0.28(+)-C4H4O6.4H2O (RS0.72ARS0.28) have been studied in the paraelectric phase [Mr = 276.32, orthorhombic, P21212,° Z = 4, F(000) = 575.04, λ(Mo Kα1) = 0.70926 Å]; T = 213 (1), 253 (1) and 293 (1) K. The crystal data are as follows: (I) at T = 213 (1) K: R = 0.0424, wR = 0.0399, number of reflections = 3414, a = 11.899 (2), b = 14.273 (2), c = 6.211 (1) Å, V = 1054.9 (2) Å3, Dx = 1.740 g cm−3; (II) at T = 253 (1) K: R = 0.0498, wR = 0.0442, number of reflections = 3284, a = 11.929 (1), b = 14.297 (1), c = 6.221 (1) Å, V = 1061.0 (2) Å3, Dx = 1.730 g cm−3; (III) at T = 293 (1) K: R = 0.0473, wR = 0.0392, number of reflections = 3179, a = 11.955 (1), b = 14.317 (1), c = 6.231 (1) Å, V = 1066.5 (1) Å3, Dx = 1.721 g cm−3. X-ray investigations reveal details of structural change with temperature in the paraelectric phase. The carboxylate anion O(3)—C(4)—O(4) in the tartrate molecule is displaced along the a axis as the temperature decreases; moreover, the O(8) atom is displaced in the opposite direction against the shift of the carboxylate anion. The temperature dependence of the thermal motions of O(8) shows different behavior from the other O atoms of the water molecules. The amplitude of the thermal motion of O(8) does not tend to zero at T = 0 K, while the other O atoms of the water molecules tend to zero.

A study on α-RuCl3 crystal structure by scanning tunneling microscopy

1989 ◽  
Vol 47 ◽  
pp. 30-31
Author(s):  
H.-J. Cantow ◽  
H. Hillebrecht ◽  
S. Magonov ◽  
H. W. Rotter ◽  
G. Thiele
Keyword(s):  
Crystal Structure ◽  
Density Distribution ◽  
Scanning Tunneling Microscopy ◽  
Electron Density ◽  
Structure Determination ◽  
Electron Density Distribution ◽  
Scanning Tunneling ◽  
Monoclinic Space Group ◽  
Tunneling Microscopy ◽  
X Ray

From X-ray analysis, the conclusions are drawn from averaged molecular informations. Thus, limitations are caused when analyzing systems whose symmetry is reduced due to interatomic interactions. In contrast, scanning tunneling microscopy (STM) directly images atomic scale surface electron density distribution, with a resolution up to fractions of Angstrom units. The crucial point is the correlation between the electron density distribution and the localization of individual atoms, which is reasonable in many cases. Thus, the use of STM images for crystal structure determination may be permitted. We tried to apply RuCl3 - a layered material with semiconductive properties - for such STM studies. From the X-ray analysis it has been assumed that α-form of this compound crystallizes in the monoclinic space group C2/m (AICI3 type). The chlorine atoms form an almost undistorted cubic closed package while Ru occupies 2/3 of the octahedral holes in every second layer building up a plane hexagon net (graphite net). Idealizing the arrangement of the chlorines a hexagonal symmetry would be expected. X-ray structure determination of isotypic compounds e.g. IrBr3 leads only to averaged positions of the metal atoms as there exist extended stacking faults of the metal layers.

X-ray Crystal Structure of ?9-THC-tosylate

Planta Medica ◽  
2008 ◽  
Vol 74 (03) ◽  
Author(s):  
W Gul ◽  
P Carvalho ◽  
D Slade ◽  
M Avery ◽  
JR Duchek ◽  
...  
Keyword(s):  
Crystal Structure ◽  
X Ray

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

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