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151.
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153.
A. Coetzee M. E. Brown D. J. Eve C. A. Strydom 《Journal of Thermal Analysis and Calorimetry》1994,41(2-3):357-385
Both isothermal and programmed temperature experiments have been used to obtain kinetic parameters for the dehydrations and
the decompositions in nitrogen of the mixed metal oxalates: FeCu(ox)2·3H2O, CoCu(ox)2·3H2O and NiCu(ox)2·3.5H2O, [ox=C2O4]. Results are compared with those reported for the thermal decompositions of the individual metal oxalates, Cuox, Coox·2H2O, Niox·2H2O and Feox·2H2O. X-ray photoelectron spectroscopy (XPS) was also used to examinee the individual and the mixed oxalates.
Dehydrations of the mixed oxalates were mainly deceleratory processes with activation energies (80 to 90 kJ·mol−1), similar to those reported for the individual hydrated oxalates. Temperature ranges for dehydration were broadly similar
for all the hydrates studied here (130 to 180°C).
Decompositions of the mixed oxalates were all complex endothermic processes with no obvious resemblance to the exothermic
reaction of Cuox, or the reactions of physical mixtures of the corresponding individual oxalates.
The order of decreasing stability, as indicated by the temperature ranges giving comparable decomposition rates, was NiCu(ox)2>CoCu(ox)2>FeCu(ox)2, which also corresponds to the order of increasing covalency of the Cu−O bonds as shown by XPS.
In celebration of the 60th birthday of Dr. Andrew K. Galwey 相似文献
154.
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The thermal analysis of CoC2O4·2H2O, Co(HCOO)2·2H2O and Co(CH3COO)2·4H2O was carried out with simultaneous TG-DTG-DTA measurements under non-isothermal conditions in air and argon atmospheres.
The intermediates and the end products of decomposition were characterised by X-ray diffraction and IR and UV-VIS spectroscopy.
The decomposition of the studied compounds occur in several stages. The first stage of dissociation of each compound is dehydration
both in air and argon. The next stages differ in air and argon. The final product of the decomposition of each compound in
air is Co3O4. In argon it is a mixture of Co and CoO for cobalt(II) oxalate and cobalt(II) formate but CoO for cobalt(II) acetate.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
157.
A simple and versatile protocol, based on use of solid phase extraction on strong ion exchangers and off-line detection by flame atomic absorption spectrometry, was devised to fractionate iron and zinc in common dietary food and beverages products, i.e., bee honeys, fruit juices and tea infusions. In the procedure proposed, cation exchanger Dowex 50Wx4 and anion exchanger Dowex 1x4 were used separately for distinguishing broadly meant the cationic metal fraction and the fraction of stable anionic metal complexes, respectively, after retention of metal species and their exhaustive elution by means of a 4.0 mol l−1 HCl solution. The third fraction, referred to the residual metal species, was retrieved by difference between total soluble metal contents and sum of metal quantities in separated cationic and anionic fractions. The fractionation pattern observed for both metals was described and discussed. 相似文献
158.
159.
Icbudak H. Heren Z. Kose D. Ali Necefoglu H. 《Journal of Thermal Analysis and Calorimetry》2004,76(3):837-851
The mixed-ligand p-hydroxybenzoate complexes of Ni(II), Cu(II) and Zn(II) with nicotinamide and N,N-diethylnicotinamide were synthesized and
characterized by elemental analysis, magnetic susceptibility measurements and mass spectrometry. The thermal behavior of the
complexes was studied by simultaneous TG, DTG and DTA methods in static air atmosphere. The infrared spectral characteristics
of the complexes are also discussed. The complexes contain two water molecules, two p-hydroxybenzoato (p-hba) and two nicotinamide (na) (or diethylnicotinamide (dena)) ligands per formula unit. In these complexes,
all ligands are coordinated to the metal ion as monodendate ligands. In Zn(II)-na and Cu(II)-dena complexes, thep-hydroxybenzoate behaves as bidentate chelating ligand through carboxylic oxygen atoms. The decomposition pathways and the
stability of the complexes are interpreted in the terms of the structural data. The final decomposition products were found
to be the respective metal oxides.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
160.
Pasynskii A. A. Semenova N. I. Torubaev Yu. V. Belousov P. V. Lyssenko K. A. Dobrokhotova Zh. V. 《Russian Chemical Bulletin》2001,50(11):2215-2220
Transmetallation of the Fe3(3-X)2(CO)9 clusters (X = S, Se, or Te) under the action of (-C8H12)PtCl2 afforded new heterometallic clusters (-C8H12)Pt(3-X)2Fe2(CO)6 (2—4, respectively), which were characterized by X-ray diffraction analysis. The (-C8H12)Pt fragment in these clusters is bound to two 3-bridging chalcogen atoms X. The iron atoms are linked to each other. The coordination environment about the Pt atom is planar-square; the Pt...Fe distance is larger than 3.2 . In the synthesis of cluster 4, a new Pt complex was also obtained for which the structure (CO)2Pt(-Te)2Pt(CO)2 (5) was proposed. According to the results of differential scanning calorimetry, thermal decomposition of complex 5 gave rise only to PtTe, whereas complexes 1—4 gave products with the empirical formula Fe2PtX2C2O2. The influence of the steric effects on the geometry of the clusters is discussed. 相似文献