Une étude cristallographique: Superspace description of a commensurate composite cocrystal of 4,4'-dinitrobiphenyl and biphenyl

CrystEngComm ◽  
2021 ◽  
Author(s):  
Toms Rekis ◽  
Sitaram Ramakrishnan ◽  
Surya Rohith Kotla ◽  
Jin-Ke Bao ◽  
Claudio Eisele ◽  
...  
Keyword(s):  
Composite Crystal ◽  
Superspace Description

We report the structure of a 3:1 cocrystal of 4,4'-dinitrobiphenyl and biphenyl. The cocrystal can be regarded as a commensurate column composite crystal and therefore is described in superspace. The...

Superspace description of the structure of the composite crystal urea/n-octane at room temperature

2001 ◽  
Vol 57 (3) ◽  
pp. 378-385 ◽  
Author(s):  
I. Peral ◽  
G. Madariaga ◽  
V. Petricek ◽  
T. Breczewski
Keyword(s):  
Inclusion Compounds ◽  
Room Temperature ◽  
Structural Model ◽  
Common Pattern ◽  
Tunnel Wall ◽  
Final Model ◽  
Lack Of Information ◽  
Composite Crystal ◽  
Unified View ◽  
Superspace Description

A structural model for the composite crystal urea/n-octane is proposed. Despite the lack of information from the largely disordered guest substructure, the final model is consistent with the collected diffraction pattern. The use of the superspace approach stresses the composite character of the inclusion compounds and makes easier a unified view of the whole urea/n-alkane family. In particular, a comparison between the octane and heptadecane derivatives shows a common pattern for the origin of the modulation of the guest chains based on the distribution of the NH_{2} groups within each tunnel wall.

Description and symmetry of aperiodic crystals

2018 ◽  
Author(s):  
Ted Janssen ◽  
Gervais Chapuis ◽  
Marc de Boissieu
Keyword(s):  
Time Reversal ◽  
Mathematical Concept ◽  
New Materials ◽  
Magnetic Systems ◽  
Atomic Structures ◽  
Modulated Phases ◽  
Quasiperiodic Functions ◽  
Aperiodic Crystals ◽  
Superspace Description

This chapter first introduces the mathematical concept of aperiodic and quasiperiodic functions, which will form the theoretical basis of the superspace description of the new recently discovered forms of matter. They are divided in three groups, namely modulated phases, composites, and quasicrystals. It is shown how the atomic structures and their symmetry can be characterized and described by the new concept. The classification of superspace groups is introduced along with some examples. For quasicrystals, the notion of approximants is also introduced for a better understanding of their structures. Finally, alternatives for the descriptions of the new materials are presented along with scaling symmetries. Magnetic systems and time-reversal symmetry are also introduced.

A superspace description for the morphology of quasicrystals I. The Fibonacci chain of atoms

1995 ◽  
Vol 71 (6) ◽  
pp. 1083-1100 ◽  
Author(s):  
T. G. A. Heijmen ◽  
M. Kremers ◽  
H. Meekes
Keyword(s):  
Superspace Description

scholarly journals High-Temperature Evolution of the Incommensurate Composite Crystal Ca0.83CuO2

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 630
Author(s):  
Lara Righi ◽  
Marco Merlini ◽  
Mauro Gemmi
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Spatial Arrangement ◽  
Structural Rearrangement ◽  
Interatomic Distances ◽  
Modulated Structure ◽  
Octahedral Sites ◽  
Synchrotron Powder Diffraction ◽  
Composite Crystal ◽  
Ca Ions

The crystal structure of the composite crystal Ca0.83CuO2 was investigated by synchrotron powder diffraction at high temperature. The incommensurate modulated structure was firstly analyzed at room temperature (RT) and successfully solved by adopting the (3D + 1)-dimensional symmetry P21/m(α0γ)0s. The composite crystal is featured by a non-uniform distribution of Ca ions occupying octahedral sites formed by the spatial arrangement by the infinite 1D CuO2 chains. By approaching 500 K, Ca0.83CuO2 undergoes a structural rearrangement ruled by the shrinking of the Ca interatomic distances. The high-temperature crystalline phase is characterized by a different incommensurate periodicity requiring the recombination of the Ca/CuO2 balance featuring the composite intergrowth of the two almost independent sub-structures. We ascertain that the new crystalline form is stable up to 950 K near to the limit of the thermal decomposition.

Preparation, Thermal and Sensitivity Properties of Nano‐Sized Spherical Nitrocellulose Composite Crystal

2020 ◽  
Vol 45 (8) ◽  
pp. 1194-1203 ◽  
Author(s):  
Xiangjun Meng ◽  
Chengkai Pu ◽  
Pengteng Cui ◽  
Zhenggang Xiao
Keyword(s):  
Composite Crystal

scholarly journals Efficient continuous-wave and passively Q-switched pulse laser operations in a diffusion-bonded sapphire/Er:Yb:YAl_3(BO_3)_4/sapphire composite crystal around 155 μm

2018 ◽  
Vol 26 (1) ◽  
pp. 419 ◽  
Author(s):  
Yujin Chen ◽  
Yanfu Lin ◽  
Jianhua Huang ◽  
Xinghong Gong ◽  
Zundu Luo ◽  
...  
Keyword(s):  
Pulse Laser ◽  
Continuous Wave ◽  
Composite Crystal

1.3-ns pulse, compact passively Q-switched microchip green laser by Nd:YAG/Cr4+:YAG composite crystal

Laser Physics ◽  
2011 ◽  
Vol 21 (4) ◽  
pp. 690-694 ◽  
Author(s):  
X. -Q. Yang ◽  
H. -X. Wang ◽  
J. -F. Yang ◽  
B. -T. Zhang ◽  
H. -T. Huang
Keyword(s):  
Green Laser ◽  
Composite Crystal

Nonuniform pumped passively Q-switched laser using Nd:YAG/Cr4+:YAG composite crystal with high-pulse energy

2019 ◽  
Vol 58 (03) ◽  
pp. 1
Author(s):  
Meigui Li ◽  
Yingxiong Qin ◽  
Chaojun Wang ◽  
Xiaodong Liu ◽  
Sichen Long ◽  
...  
Keyword(s):  
Pulse Energy ◽  
High Pulse Energy ◽  
Composite Crystal ◽  
High Pulse

Design and assembly of a chiral composite metal–organic framework for efficient asymmertric sequential transformation of alkenes to amino alcohols

2019 ◽  
Vol 55 (62) ◽  
pp. 9136-9139 ◽  
Author(s):  
Qingchun Xia ◽  
Chen Yuan ◽  
Yongxin Li ◽  
Yong Cui
Keyword(s):  
Metal Organic Framework ◽  
Amino Alcohols ◽  
Composite Crystal ◽  
Metal Organic ◽  
Sequential Transformation ◽  
Organic Framework

A composite crystal MOF was constructed with Al(salen) inside, which was encapsulated by Mn(salen) outside. The resulting composite crystal appeared to be highly enantioselective for the alkene epoxidation/epoxide aminolysis reactions.

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