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Layers Alternating (layer + alternating)

Distribution by Scientific Domains
Chemistry40%

Selected Abstracts

Carbon Nanotube Composites: Hierarchical Composites of Single/Double-Walled Carbon Nanotubes Interlinked Flakes from Direct Carbon Deposition on Layered Double Hydroxides (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2010
Mater.
On page 677, M. Q. Zhao et al. report the fabrication of a hierarchical composite combining one-dimensional single/double walled carbon nanotubes (CNTs) and two-dimensional flakes through direct carbon deposition on layered double hydroxides. The composites can be easily transformed into continuously interlinked CNT layers alternating with calcined lamellar flakes structure. They are found to have the potential for applications in a number or areas, including as an excellent filler for strong polyimide film. [source]

Hierarchical Composites of Single/Double-Walled Carbon Nanotubes Interlinked Flakes from Direct Carbon Deposition on Layered Double Hydroxides

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2010
Meng-Qiang Zhao
Three-dimensional hierarchical nanocomposites consisting of one-dimensional carbon nanotubes (CNTs) and two-dimensional lamellar flakes (such as clay, layered double hydroxides) show unexpected properties for unique applications. To achieve a well-designed structure with a specific function, the uniform distribution of CNTs into the used matrix is a key issue. Here, it is shown that a hierarchical composite of single/double-walled CNTs interlinked with two-dimensional flakes can be constructed via in-situ CNT growth onto layered double hydroxide (LDH) flakes. Both the wall number and diameter of the CNTs and the composition of the flakes can be easily tuned by changing the proportion of the transition metal in the LDH flakes. Furthermore, a structure with continuously interlinked CNT layers alternating with lamellar flakes is obtained after compression. The hierarchical composite is demonstrated to be an excellent filler for strong polyimide films. This study indicates that LDH is an extraordinary catalyst for the fabrication of hierarchical composites with high-quality single/double-walled CNTs. The as-obtained CNTs/calcined LDHs nanocomposite is a novel structural platform for the design of mechanically robust materials, catalysts, ion-transportation, energy-conversion, and other applications. [source]

Structural analysis of lithium lanthanum titanate with perovskite structure

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2009
Koji Ohara
Abstract Neutron and high-energy X-ray diffraction analysis of polycrystalline La4/3-xLi3xTi2O6 have been performed to clarify the extent of disorder of the distribution of La and Li ions and to understand the relation of these distributions to ionic conduction. The distributions of the La and Li ions in a 10 × 10 × 20 cubic box (i.e., 10 × 10 × 10 unit cell) super-structure, in which Ti and O atoms are fixed onto their regular sites, were obtained by the reverse Monte Carlo (RMC) structural modelling of both diffraction data sets. When the occupancy of La ions in the planes perpendicular to the c-axis is analysed, one can find a La-rich and La-poor layers alternating, which is consistent with the results of earlier Rietveld analysis (Stramare et al., Chem. Mater. 15, 3974 (2003) [1]). Of particular interest, the Li ions are found mainly on the interstitial sites between the O-3 triangle plane of the TiO6 octahedron and a La ion, which is different from the earlier work (Yashima et al., J. Am. Chem. Soc. 127, 3491 (2005) [2]). (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Polymorphism in the spin-crossover ferric complexes [(TPA)FeIII(TCC)]PF6

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2009
Eric Collet
We have identified two polymorphs of the molecular complex [(TPA)Fe(III)(TCC)]PF6 [TPA = tris(2-pyridylmethyl)amine and TCC = 3,4,5,6-tetrachlorocatecholate dianion]: one is monoclinic and the other is orthorhombic. By lowering the temperature both undergo a thermal spin-crossover between a high-spin (S = 5/2) and a low-spin (S = 1/2) state, which we detected by magnetic, optical and X-ray diffraction measurements. The thermal crossover is only slightly shifted between the polymorphs. Their crystalline structures consist of similar cation layers alternating with PF6 anion layers, packed differently in the two polymorphs. The magnetic and optical properties of the polymorphs are presented. [source]

CdBiO2Cl: synthesis and powder structure solution

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2001
Sergei D. Kirik
The title compound, cadmium bismuth dioxide chloride, CdBiO2Cl, was obtained as a white powder by reaction of solid BiOCl with CdO at 973,K. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques, including direct methods for atom location and Rietveld fitting for the final refinement. Being monoclinic, the crystal structure can be related to tetragonal Sillen layered phases. The main structural elements present are CdBiO2+ pleated metal,oxy­gen layers alternating with Cl layers along the c axis, whereas along the b axis, all atoms are on mirror planes. The formation of a strong Cd,Cl bond draws the layers together, causing layer deformation and a monoclinic distortion in the layer arrangement. [source]