scholarly journals Generalizing the Chiral Self-Assembly of Spheres and Tetrahedra to Non-Spherical and Polydisperse Molecules in (C70)x(C60)(1-x)(SnI4)2

2021 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Solid Solution ◽  
Self Assembly ◽  
Lattice Parameter ◽  
Nonspherical Particles ◽  
High Symmetry ◽  
Chiral Phase ◽  
Cubic Lattice ◽  
Vegard’S Law ◽  
Chiral Materials ◽  
Chiral Crystals

We describe the spontaneous chiral self-assembly of C<sub>70</sub> with SnI<sub>4</sub> as well as a mixture of C<sub>60</sub> and C<sub>70</sub> with SnI<sub>4</sub>. Macroscopic single crystals with the formula (C<sub>70</sub>)<sub>x</sub>(C<sub>60</sub>)<sub>1-x</sub>(SnI<sub>4</sub>)<sub>2</sub> (x = 0-1) are reported. C<sub>60</sub>, which is spherical, and C<sub>70</sub>, which is ellipsoidal, form a solid solution in these crystals, and the cubic lattice parameter of the chiral phase linearly increases as x grows from 0 to 1 in accordance with Vegard’s law. Our results demonstrate that nonspherical particles and polydispersity are not an impediment to the growth of chiral crystals from high-symmetry achiral precursors, providing a route to assemble achiral particles including colloidal nanocrystals and engineered nanostructures into chiral materials without the need to use external templates.<br>

scholarly journals Generalizing the Chiral Self-Assembly of Spheres and Tetrahedra to Non-Spherical and Polydisperse Molecules in (C70)x(C60)(1-x)(SnI4)2

2021 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Solid Solution ◽  
Self Assembly ◽  
Lattice Parameter ◽  
Nonspherical Particles ◽  
High Symmetry ◽  
Chiral Phase ◽  
Cubic Lattice ◽  
Vegard’S Law ◽  
Chiral Materials ◽  
Chiral Crystals

We describe the spontaneous chiral self-assembly of C<sub>70</sub> with SnI<sub>4</sub> as well as a mixture of C<sub>60</sub> and C<sub>70</sub> with SnI<sub>4</sub>. Macroscopic single crystals with the formula (C<sub>70</sub>)<sub>x</sub>(C<sub>60</sub>)<sub>1-x</sub>(SnI<sub>4</sub>)<sub>2</sub> (x = 0-1) are reported. C<sub>60</sub>, which is spherical, and C<sub>70</sub>, which is ellipsoidal, form a solid solution in these crystals, and the cubic lattice parameter of the chiral phase linearly increases as x grows from 0 to 1 in accordance with Vegard’s law. Our results demonstrate that nonspherical particles and polydispersity are not an impediment to the growth of chiral crystals from high-symmetry achiral precursors, providing a route to assemble achiral particles including colloidal nanocrystals and engineered nanostructures into chiral materials without the need to use external templates.<br>

Self-Assembly of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI4 molecules through spontaneous self-assembly. The SnI<sub>4</sub> tetrahedra template the Sn atoms into a chiral cubic three-connected net of the SrSi<sub>2</sub> type that is held together by van der Waals forces. Our results represent the remarkable emergence of a self-assembled chiral material from two of the most highly symmetric molecules, demonstrating that almost any molecular, nanocrystalline, or engineered precursor can be considered when designing chiral assemblies.

An Approach to the Solid Solution Problem Using a Computerized Identification Technique

1969 ◽  
Vol 13 ◽  
pp. 539-549
Author(s):  
Gerald G. Johnson ◽  
Frank L. Chan
Keyword(s):  
Solid Solution ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Powder Diffraction File ◽  
X Ray ◽  
Complete Solid Solution ◽  
Vegard’S Law ◽  
Identification Technique ◽  
Approximate Composition ◽  
End Members

Since for most real systems, solid solution effects influence the position and intensity of the x-ray powder diffraction pattern, it is desirable and necessary to have an automatic system which will identify standard reference phases regardless of the amount of solid solution. Using the system CdS-ZnS, where the lattice parameter a0 changes from 4.136 to 3.820Å, with complete solid solution over the entire range of composition, an illustrative study was made. This work presents the results obtained from a computer analysis of the powder pattern obtained. It has been found that if the starting chemistry is known and the end members of the series are in the ASTM Powder Diffraction File, that the solid solution can be identified. Once the phases present are identified, a plot following Vegard's law yields the approximate composition of the sample under consideration. These two methods of compositional determination agree quite well. Examples of the computer system and description of the program input and output with interpretation of the results will be discussed.

scholarly journals Structural properties of CoxCu1−xFe2O4 solid solution**

2021 ◽  
Vol 30 (1) ◽  
pp. 220-227
Author(s):  
Natheer B. Mahmood ◽  
Farqad R. Saeed ◽  
Kadhim R. Gbashi ◽  
Ali Hamodi ◽  
Zahraa M. Jaffar
Keyword(s):  
Solid Solution ◽  
Lattice Parameter ◽  
Peak Position ◽  
Unit Cell ◽  
Factor X ◽  
Ionic Radii ◽  
Peak Intensity ◽  
Vegard’S Law ◽  
Density Of Electrons ◽  
Xrd Patterns

Abstract Crystallography information files (CIF) were designed formed CoxCu1−xFe2O4 solid solution with the substitution factor x=0 to 1 with an increment of 0.1 depending on Vegard's law by using crystallography software. The effect of the substitution factor has been studied on some parameters and properties of the Co-Cu ferrite system, such as the effect of substitution factor on the lattice parameter, the volume of unit cell, and the density of the unit cell. Also, XRD patterns were estimated by crystallography software depending on the mathematical models of XRD. The XRD results showed a slight shift in the peak position varying with the substitution factor, these are due to the change in lattice parameter caused by the substitution of ions with different ionic radii. XRD also showed an increment in peak intensity varying with the substitution factor, that's due to an increase in the concentration of Cu which led to an increase in the density of electrons.

scholarly journals Temperature-influenced Substitution of Si in Ti3(Si,Al)C2  Solid Solution

2020 ◽  
Author(s):  
Jun JI ◽  
Zirun YANG ◽  
Zhenyu ZHANG ◽  
Dechun LI ◽  
Zhi Wang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Sintering Temperature ◽  
Lattice Parameter ◽  
Chemical Compositions ◽  
X Rays ◽  
Experiment Data ◽  
Substitution Process ◽  
Vegard’S Law ◽  
Different Temperatures ◽  
Scanning Electron

Abstract High-pure Ti3(Si,Al)C2 solid solutions were synthesized in the range of 1473 to 1773K. The microstructures and chemical compositions of all samples were characterized by X-rays diffraction (XRD) and scanning electron microscope (SEM). It was worthy noted that experimentally determined lattice parameter c of Ti3(Si,Al)C2 crystal decreased with the increasing of sintering temperature. The contents of Si and Al elements in solid solution were conducted by Vegard’s Law. Gibbs energy differences (△G) of substitution behaviors of Si at different temperatures were also listed. With the increase of temperature, △G of Eq. Ti3(Si0.75Al0.25)C2+0.25Si→Ti3SiC2+0.25Al were negative and decreased gradually, which means that the transformation from Ti3(Si,Al)C2 to Ti3SiC2 was spontaneous and had a greater tendency in higher temperatures. By analyzing the experiment data, a possible mechanism of the substitution process of Si in various temperatures was determined.

scholarly journals A Chiral Van Der Waals Material Self-Assembled from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
The Self ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Molecular Precursor ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI<sub>4</sub> molecules through spontaneous self-assembly. Our results represent the remarkable emergence of chirality from the self-assembly of two of the most highly symmetric molecules, demonstrating that almost any molecular precursor can be considered when designing chiral assemblies.

Self-Assembly of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI4 molecules through spontaneous self-assembly. The SnI<sub>4</sub> tetrahedra template the Sn atoms into a chiral cubic three-connected net of the SrSi<sub>2</sub> type that is held together by van der Waals forces. Our results represent the remarkable emergence of a self-assembled chiral material from two of the most highly symmetric molecules, demonstrating that almost any molecular, nanocrystalline, or engineered precursor can be considered when designing chiral assemblies.

scholarly journals Synthesis of Pd-Fe System Alloy Nanoparticles by Pulsed Plasma in Liquid

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1068 ◽  
Author(s):  
Shota Tamura ◽  
Tsutomu Mashimo ◽  
Kenta Yamamoto ◽  
Zhazgul Kelgenbaeva ◽  
Weijan Ma ◽  
...  
Keyword(s):  
Solid Solution ◽  
Solution Structure ◽  
Lattice Parameter ◽  
Face Centered Cubic ◽  
Pulsed Plasma ◽  
X Ray ◽  
Transmission Electron ◽  
Vegard’S Law ◽  
Face Centered ◽  
Plasma In Liquid

We synthesized Pd-Fe series nanoparticles in solid solution using pulsed plasma in liquid with Pd-Fe bulk mixture electrodes. The Pd-Fe atomic percent ratios were 1:3, 1:1, and 3:1, and the particle size was measured to be less than 10 nm by high-resolution transmission electron microscopy (HR-TEM). The nanoparticles showed face-centered cubic structure. The lattice parameter increased with increasing Pd content and followed Vegard’s law, and energy-dispersive X-ray spectra were consistent with the ratios of the starting samples, which showed a solid solution state. The solid solution structure and local structure were confirmed by HR-TEM and X-ray absorption fine structure.

The usefulness of high index low symmetry zone axes for holz line analysis

1987 ◽  
Vol 45 ◽  
pp. 384-385
Author(s):  
C. M. Sung ◽  
D. B. Williams
Keyword(s):  
Lattice Parameter ◽  
High Order ◽  
Zone Axis ◽  
High Index ◽  
High Symmetry ◽  
Second Phases ◽  
Line Patterns ◽  
Low Symmetry ◽  
Line Analysis

Researchers have tended to use high symmetry zone axes (e.g. <111> <114>) for High Order Laue Zone (HOLZ) line analysis since Jones et al reported the origin of HOLZ lines and described some of their applications. But it is not always easy to find HOLZ lines from a specific high symmetry zone axis during microscope operation, especially from second phases on a scale of tens of nanometers. Therefore it would be very convenient if we can use HOLZ lines from low symmetry zone axes and simulate these patterns in order to measure lattice parameter changes through HOLZ line shifts. HOLZ patterns of high index low symmetry zone axes are shown in Fig. 1, which were obtained from pure Al at -186°C using a double tilt cooling holder. Their corresponding simulated HOLZ line patterns are shown along with ten other low symmetry orientations in Fig. 2. The simulations were based upon kinematical diffraction conditions.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

Sign in / Sign up

Export Citation Format

Share Document