STUDIES ON THE SYNTHETIC, STRUCTURAL, ELECTRICAL, AND MAGNETIC-PROPERTIES OF THE NEW LAYERED OXIDES LN(2)MCO(2)O(7) (LN=SM, GD, M=SR, BA)

Three new oxides Ln(2)MCo(2)O(7) (Ln = Sm, Gd; M = Sr, Ba) have been synthesized in solid state reaction method. The powder X-ray diffraction spectra show that they are all isostructural with Sr3Ti2O7. The electrical resistivities in the temperature range 300-1100 K show that they are all semiconductors, and a transition to metals is observed at 1053, 1053, and 573 K for Sm2SrCo2O7, Gd2SrCo2O7, and Sm2BaCo2O7, respectively. The magnetic suspectivities of Gd2SrCo2O7 in the temperature range 300-673 K fit the Curie-Weiss law well. A plateau is observed in the curves of Sm(2)MCo(2)O(7) (M = Sr, Ba) which is attributed to the configuration state change of Co(III) from low spin to high spin. (C) 1995 Academic Press, Inc.

Synthesis and catalytic properties of layered double hydroxides pillared by heteropolyoxometalate

Layered double hydroxides (LDHs) pillared with heteropolyoxometalate have been synthesized via both restructuring of hydrotalcite-like compounds and direct anion exchange under microwave field. LDHs and their derivatives are both found to be efficient for alkylation of isobutane with butene with a higher butene conversion and selectivity towards C-8(0).

THE SYNTHESIS AND PHYSICAL-PROPERTIES OF THE NEW LAYERED LANTHANIDE ALKALINE-EARTH COBALT OXIDES [LN2MCO2O7 (LN=SM,GD M=SR,BA)]

Three new oxides Sm2SrCo2O7, Sm2BaCo2O7 and Gd2SrCo2O7 have been successfully synthesized by a solid state reaction method.The X - Ray diffraction spectra show that they are all isostructural with Sr8Ti 2O7, Ln2SrCo2O7(Ln=Sm, Gd) crystallized in the tetra

Alrylation Over Layered Double Hydrotalcites Pillared by Heteropolyoxometalate Catalysts

Layered double hydroxides (LDHs) pillared with heteropolyoxo-metalate have been synthesized via both restructuring of hydrotalcite-like compounds and direct anion exchange under microwave field. LDHs and their derivatives are both found to be efficiency f

ALKYLATION OF ISOBUTANE WITH BUTENE OVER LAYERED DOUBLE HYDROXIDE PILLARED HETEROPOLYOXOMETALATE ACID-BASE CATALYSTS

[Si(W2O7)(6)](8-) pillared LDH structure hydroxides were synthesized by the method of restructuring of the thermally decomposed hydrotalcite-like compounds for Zn-Al and Mg-Al oxide systems. [P(W2O7)(6)](8-) pillared Ni-Al LDH structure hydroxide was synt

Unprecedented 5,5-connected (4(7)center dot 6(3)) (4(8)center dot 6(2)) structural topology: A lead biphosphonate with double layered structure

A new lead(II) phosphonate, Pb[(PO3)(2)C(OH)CH3]center dot H2O (1) was hydrothermally synthesized and characterized by IR, elemental analysis, UV, TGA, SEM, and single crystal X-ray diffraction analysis. X-ray crystallographic study showed that complex 1 has a two-dimensional double layered hybrid structure containing interconnected 4- and 12-membered rings and shows an unusual (5,5)-connected (4(7) . 6(3)) (4(8) .6(2)) topology. (C) 2008 Elsevier B.V. All rights reserved.

Preparation and characteristic of a new class of silica/polyimide nanocomposites

A new class of silica/polyimide nanocomposites was successfully prepared by the sol-gel reaction, tetraethoxysilane, (TEOS), was hydrolyzed by the water released from imidization at low and high temperature. Silica particles with diameter of around 30-50 nm were observed in the hybrid films by scanning electron microscopy. The flame retardance, decomposition temperature and glass transition temperature of the film increased with increasing silica content. The tensile strength increased slightly while the elongation at break of the films decreased with increasing silica content. (C) 2002 Kluwer Academic Publishers.