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A new family of layered rare-earth hydroxides rigidly pillared by sulfate ions has been synthesized through homogeneous precipitation of lanthanide sulfate salts driven by hydrolysis of hexamethylenetetramine. Obtained materials were composed of aggregated thin platelet microcrystallites. Chemical analysis indicates that these samples have a general chemical formula of Ln2(OH)4SO4·nH2O (Ln = Pr to Tb; n∼ 2). The compounds are crystallized in an A-base-centered orthorhombic structure with unit cell dimensions of a∼ 0.63 nm, b∼ 1.6−1.7 nm, and c∼ 0.37 nm. Fourier transform infrared (FT−IR) spectra indicate that sulfate ions are in a trans-bidentate arrangement, which suggests that sulfate ions bridge adjacent rare-earth hydroxide layers through direct coordination to lanthanide cations. The compounds showed two-step weight loss (200−275 °C and ∼350 °C) in the heating process, which can be ascribed to dehydration and dehydroxylation, respectively. Robust lanthanide−sulfate chelate bondings can be inherited even after calcination above 450 °C to yield layered oxysulfates of Ln2O2SO4. Trends in compositional and structural features as well as bonding aspects of hydroxyl groups and sulfate ions across the series, Pr to Tb, are described. Eu and Tb samples exhibited photoluminescence (PL) properties with characteristic red and green emissions, respectively, through both the direct excitation of lanthanide ions themselves and the charge-transfer channels between lanthanide ions and surrounding oxygen atoms. [ABSTRACT FROM AUTHOR]

Abstract: SnO2 urchin-like structures composed of nanorods with diameters of 10–15nm and lengths of 50–70nm have been hydrothermally synthesized via a H2O2-assisted route without any surfactant, using SnCl2 as raw material. With the addition of methenamine (HMT), SnO2 hollow microspheres with diameters of 2–3μm and shell thickness of 60–140nm were also prepared. The as-obtained products were examined using diverse techniques including X-ray powder diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), high-resolution TEM and photoluminescence spectra. The gas sensitivity experiments have demonstrated that the as-synthesized SnO2 materials exhibit good sensitivity to alcohol vapors, which may offer potential applications in gas sensors. [Copyright &y& Elsevier]

The article offers information on the article "Layered Rare Earth Hydroxides: Structural Aspects and Photoluminescence Properties" by J. Liang and others, published in the periodical "Structure and Bonding" in 2016.

Abstract: Large-scale copper sulfide polycrystalline nanorods have been solvothermally synthesized through a Cu(acac)2 precursor decomposition and reaction route. X-ray diffraction (XRD) showed that the product was hexagonal phase CuS with lattice constants of a =3.795Å and c =16.42Å. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) investigated the morphology of the product under the different growth conditions. PL spectra indicated that the rod-shaped product had emission peaks at 414 and 437.5nm when the excitation wavelength was 371.5nm, but the CuS dendrite did not demonstrate emission peaks at the same condition. A mechanism of Cu(acac)2 micronrods decomposition and reaction with CS2 in situ was suggested based on the TEM observation. [Copyright &y& Elsevier]