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Journal of Thermal Analysis and Calorimetry
Authors: Luiz Carlos Machado, Marcos Tadeu D’Orlando de Azeredo, Hamilton Perez Soares Corrêa, Jivaldo do Rosário Matos, and Ítalo Odone Mazali

) (where Ln = La, Pr, Nd, Sm, Eu, and Gd) have been produced from the thermal decomposition of hydrated lanthanide sulfates at temperatures >1073 K for 5 h under N 2 or air [ 1 , 8 ]. Subsequent reduction of as prepared Ln 2 O 2 SO 4 under a H 2 flow (3

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probable mechanism function g (α) of the thermal decomposition reaction was deduced from multiple rate iso-temperature method, pre-exponential factor A was calculated on the basis of E a and g (α) subsequently. The kinetic ( E a , A, mechanism) and

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coordinate to the metal cations forming different carboxylate coordination compounds. In this article, we report the synthesis of nanocrystalline nickel ferrite by the thermal decomposition of some organic precursors obtained in the reaction between

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Journal of Thermal Analysis and Calorimetry
Authors: S. Šnircová, E. Jóna, R. Janík, Ľ. Lajdová, S. Lendvayová, M. Loduhová, V. Šutinská, R. Durný, P. Lizák, and S. C. Mojumdar

. The aim of this study was to investigate the effect of different steric effect of these diamines on the type of interactions with Co(II)-montmorillonite and thermal decomposition of studied materials. Experimental

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Thermal decomposition of mixed oxalates

Part I: Thermogravimetric analysis of coprecipitated zinc-copper oxalates in nitrogen

Journal of Thermal Analysis and Calorimetry
Authors: B. D. Dalvi and A. M. Chavan

The thermogravimetric analysis of several coprecipitated zinc-copper oxalates in nitrogen is reported. The thermal decompositions of these mixed oxalates show a separate single step for dehydration and decomposition in the mass loss versus temperature curve. It is found that the onset temperature decreases with composition. For example, it decreases from 380‡ for zinc oxalate to 260‡ for copper oxalate. The end-product is mixed oxides and copper metal. These studies indicate the formation of an interpenetrating structure or mixed crystals during coprecipitation. Rate parameters have been calculated for dehydration and decomposition.

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.3 Equipment and conditions The thermal decomposition behavior was measured by using a C-500 type Calvet microcalorimeter from Setaram, France, which had a high sensitivity and equipped with two 10 mL vessels. The precision of enthalpy measurement was

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Thermal decomposition of the hydrotalcite

Thermogravimetric analysis and hot stage Raman spectroscopic study

Journal of Thermal Analysis and Calorimetry
Authors: R. L. Frost, W. N. Martens, and Kristy L. Erickson

Summary  

A combination of thermogravimetry and hot stage Raman spectroscopy has been used to study the thermal decomposition of the synthesised zinc substituted takovite Zn6Al2CO3(OH)164H2O. Thermogravimetry reveals seven mass loss steps at 52, 135, 174, 237, 265, 590 and ~780C. MS shows that the first two mass loss steps are due to dehydration, the next two to dehydroxylation and the mass loss step at 265C to combined dehydroxylation and decarbonation. The two higher mass loss steps are attributed to decarbonation. Raman spectra of the hydroxyl stretching region over the 25 to 200C temperature range, enable identification of bands attributed to water stretching vibrations, MOH stretching modes and strongly hydrogen bonded CO3 2--water bands. CO3 2- symmetric stretching modes are observed at 1077 and 1060 cm-1. One possible model is that the band at 1077 cm-1is ascribed to the CO3 2- units bonded to one OH unit and the band at 1092 cm-1is due to the CO3 2- units bonded to two OH units from the Zn-takovite surface. Thermogravimetric analysis when combined with hot stage Raman spectroscopy forms a very powerful technique for the study of the thermal decomposition of minerals such as hydrotalcites.</o:p>

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The thermal decomposition of magnesium peroxoborate was studied by means of a derivatograph. It was found that the decomposition involves a sequence of reactions: dehydration and O2 evolution. The kinetic parameters were obtained in each step of the reaction. The thermal stabilities of three kinds of metal peroxoborates are discussed.

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Conflicting results have been reported by different workers on the thermal decomposition of silver carbonate, Ag2CO3. In the present study, the decomposition mechanism was elucidated by various analytical methods; gas analysis (differential thermal gas analyses) in helium, carbon dioxide and oxygen flows with and without a P2O5 trap or a KOH trap, DTA-TG in a carbon dioxide flow and high-temperature X-ray diffraction analysis in a carbon dioxide flow.

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The thermal decompositions of the even silver dicarboxylates from silver oxalate to silver sebacate were studied. In vacuum, the dicarboxylates decomposed to give metallic silver, CO2 and organic diradicals as primary products, and polymers as secondary products. The higher silver dicarboxylates were much more stable to thermal treatment than silver oxalate, probably due to the initiation of decomposition of all carboxylates except silver oxalate by the rupture of a Ag-O and not a C-C bond.

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