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ZrO2-CeO2 mixed oxides were synthesized via sol-gel process. Thermal stability, structure and morphology of samples were investigated by powder X-ray diffraction, FT-Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. In this approach, the solvent composition and Zr/Ce molar ratio have great influences on the structure and morphology of final products. With decreasing water content in the mixed solvent, specific surface area of powders increased and the single tetragonal phase was obtained. Only when the volume ratio of water and ethanol and the Zr/Ce molar ratio were 1:1, tetragonal t ''-Zr0.5Ce0.5O2 could be stabilized in powders at temperature as high as 1000 degrees C. Meanwhile, tetragonal (t') and (t '') phases coexisted in Zr0.5Ce0.5O2 solid solution without peak splitting after calcination at 1100 degrees C, further transforming into cubic and tetragonal (t') phases at 1200 degrees C. The effective activation energy for Zr0.5Ce0.5O2 nanocrystallite growth during annealing is about 5.24 +/- 0.15 kJ/mol. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.

ZrO2 powders were synthesized via sol–gel process using zirconium oxychloride octahydrate as the raw material. The effects of addition of glacial acetic acid and N,N-dimethylformamide (DMF) on crystal growth and chemical bond of powders were discussed. The structural evolution, phase transformation and morphological characteristic of powders were investigated by differential scanning calorimetric analysis (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After adding the acetic acid and DMF, the crystallite size of ZrO2 decreased from about 26.48 to 13.94 nm when calcination at 600 °C for 40 min, and the activation energy for crystal growth reduced approximately from 7.76 ± 0.62 to 2.74 ± 0.28 kJ/mol in the initial stage, while abruptly increased to 26.48 ± 1.09 kJ/mol in the later stage. The specific surface area decreased from 26.73 to 0.51 m2/g. Meanwhile, the metastable tetragonal phase could be stabilized in ZrO2 nanocrystals at 600 °C for 40 min.

Bi{sub 3.25}La{sub 0.75}Ti{sub 3}O{sub 12}(BiLT) thin films with different thickness were successfully deposited onto fused quartz by chemical solution deposition. X-ray diffraction analysis shows that BiLT thin films are polycrystalline with (0 0 2)-preferred orientation. The dispersion of refractive indices of the BiLT thin films was investigated by the optical transmittance spectrum. The optical band gap energy was estimated from the graph of (h{nu}{alpha}){sup 2} versus h{nu}. The results show that the refractive index and band-gap energy of the BiLT thin films decrease with the films thickness.

The first metallocenium metallacarboranide salts have been synthesized and isolated. The title compounds were prepared by reaction of cobaltocene and CoCl 2 or FeCl 2 with the carborane anion Et 2 C 2 B 4 H 5 - in THF solution, in which the oxidation of two M(II) metal centers to M(III) is accompanied by reduction of two B-H-B bridging protons to H 2 .

In contrast to our recently reported syntheses 2 of Co-M-Co tetradecker sandwich complexes (M=Co, Ni, Ru) via reactions of double-decker cobaltacarborane anions Cp * Co(Et 2 C 2 B 3 H 3 X) - (1 - , X=H, Me, Cl, Br, acetyl) with metal halides, reactions of the anions having X=H, Me, Et, or Cl with FeCl 2 did not produce the intended Co-Fe-Co tetradeckers.

Stacking reactions of the bridge-deprotonated Cp*Co(2,3-Et[sub 2]C[sub 2]B[sub 3]H[sub 3]-5X)[sup [minus]] complexes (X = Cl, Br, CH[sub 3], C(O)CH[sub 3], CH[sub 2]C[triple bond]CCH[sub 3], H; Cp* = [eta][sup 5]-C[sub 5]Me[sub 5]) with cobalt(II) and nickel(II) halides in THF gave, respectively, diamagnetic [Cp*Co[sup III](Et[sub 2]C[sub 2]B[sub 3]H[sub 2]X)][sub 2]Ni[sup IV] and paramagnetic [Cp*Co[sup III](Et[sub 2]C[sub 2]B[sub 3]H[sub x]X)][sub 2]Co[sup IV] tetradecker sandwich complexes. A similar reaction of the B(5)-chloro reagent using RuCl[sub 2] gave the diamagnetic trichloro complex (Cp*Co)[sub 2](2,3-Et[sub 2]C[sub 2]B[sub 3]H[sub 2]-5-Cl)(2,3-Et[sub 2]C[sub 2]B[sub 3]H-4,5[5,6]-Cl[sub 2])Ru. In all cases except the Co-Co-Co compound (X = H), the products were isolated as dark crystalline solids via chromatography on silica; decomposes on silica and was isolated via fractional crystallization from a cold solution. All of the tetradeckers are air-stable in the solid state and in solution except 3f, which is stable only as a solid. Characterization of these compounds was based on [sup 1]H, [sup 11]B, and [sup 13]C NMR (for diamagnetic species), UV-visible, and mass spectra, supported by x-ray crystallographic data on the Co-Ni-Co and Co-Co-Co dichloro compounds, the Co-Ni-Co diacetyl complex, and the Co-Ru-Co sandwich. The structurally characterized compounds are tetradecker sandwiches, slightly bent in the middle (8-15[degree]) butmore » exhibiting no significant ring slippage relative to the coordinated metal atoms. The carborane rings in these sandwiches are mutually rotated by 27-89[degree]. The electronic spectra exhibit intense absorption bands between 350 and 440 nm with extinction coefficients between 28,000 and 43,000 M[sup [minus]1] cm[sup [minus]1].« less

The mononuclear 7-vertex closo-ferracarborane cluster (C 5 Me 5 )Fe II H(Et 2 C 2 B 4 H 4 ) (1) and (C 5 Me 5 )Fe III (Et 2 C 2 B 4 H 4 ) (2) and the phenylene-linked diiron species (Et 2 C 2 B 4 H 4 )M(C 5 Me 4 -C 6 H 4 -C 5 Me 4 )M'(Et 2 C 2 B 4 H 4 ) (3, M=M'=Fe II H ; 4, M=Fe II H, M'=Fe III ; and 5, M=M'=Fe III ) were prepared and isolated via column and/or plate chromatography on silica or Al 2 O 3 . Their chemical interconversion was examined, and the air-stable products were characterized from their 1 H, 13 C, and 11 B NMR, infrared, UV-visible, mass spectra, and elemental analysis and an X-ray diffraction study of 3. The crystallographic data established the location of the Fe-H hydrogen atom in each of the two equivalent ferracarborane clusters ; this hydrogen is coordinated both to iron and to the neighboring atoms in the carborane ligand and be described as capping an Fe-B-B triangular face

The preparation and characterization of the compounds [HFe 4 (CO) 12 C] BXY (X=Y=H, Cl, Br; X=H, Y=Cl, Br, OH) are described. Geometric, spectroscopic, and Fenske-Hall quantum-chemical parameters demonstrate that these compounds are usefully described as tricoordinate boron compounds substituted with a carbido cluster. The carbido cluster [HFe 4 (CO) 12 C], as a substituent, is shown to be both a sterically demanding ligand and a strong π donor to the boron center. The unanticipated differences in the reactivity of these compounds with AlX 3 , NEt 3 , H 2 O, and THF as X and Y are varied reflect the unusual properties of this compound type. Single-crystal X-ray diffraction studies of [HFe 4 (CO) 12 C]BHX (X=Cl, Br) are reported

The synthesis and structural characterization of the first example of a boracyclopropene ring coordinated to a trimetal fragment, Fe 3 (CO) 9 [C 3 -B(H)C(H)C(Me)], are described. The compound constitutes an example of a cluster containing three transition metals that can only be reasonably considered as a six-atom cluster containing three iron, two carbon, and one boron atoms. This particular derivative of the cluster core also constitutes an example of a chiral cluster