Authors:L. Costa, G. Paganetto, G. Bertelli, and G. Camino
The thermal decomposition of SbOCl, Sb4O5Cl2 and Sb8O11Cl2 has been studied by thermogravimetry with identification of the products resulting in the condensed phase by X-ray diffraction and infrared technique. It is shown that in nitrogen SbOCl undergoes progressive stepwise thermal disproportionation to Sb2O3 and SbCl3 with formation of Sb4O5Cl2 and Sb8O11Cl2 and as intermediates. It is thus confirmed that Sb3O4Cl, suggested to be formed instead of Sb8O11Cl2, is not an intermediate of this process. An identical mechanism is observed in air but with oxidation of Sb2O3 to Sb2O4.
Authors:M. Jose John, K. Muraleedharan, V. M. Abdul Mujeeb, M. P. Kannan, and T. Ganga Devi
decomposition of solids [ 1 , 3 – 5 ]. For many oxalates, the mechanism of thermaldecomposition are well established and are commonly used as standard substances to confirm the exactness of theoretically developed models and equations of thermaldecomposition
improved by Budrugeac.
The thermaldecomposition of strontium carbonate (SrCO 3 ), which is used as the experimental example, was carried out in a 50 mL/min flow of N 2 at 0.5, 5, 7.5 K/min from
Authors:Abdellah Bahmani, Mayouf Sellami, and Noureddine Bettahar
temperatures 650, 700 and 800 °C according to the case, for 6 h.
Characterisation of powder
The produced precursors have been chemically analysed and their thermaldecomposition and behaviour were studied by classical
Authors:L. E. Muresan, E.-J. Popovici, E. Bica, A. I. Cadis, I. Perhaita, and L. Barbu Tudoran
-doped yttrium aluminate Y 3 Al 5 O 12 :Eu 3+ phosphor with garnet structure (YAG:Eu).
The aim of the study is to give a better understanding of the processes that take place during the thermaldecomposition of the precursors. Therefore thermal analysis
Authors:Elena Lizarraga, C. Zabaleta, and J. Palop
The thermal decomposition of a series of compounds has been studied by thermogravimetry, mass spectrometry, nuclear magnetic
resonance and elemental analysis. The combined use of mass spectrometry and thermogravimetry (MS and TG) in the analysis of
these compounds has allowed characterization of the fragmentation pattern which was the objective of this research. The gaseous
products, volatile condensed products and solid residues were identified by NMR and MS. Based on the product of thermal decomposition,
the mechanism of thermal decomposition has been derived.
Authors:T. Gangadevi, M. Subba Rao, and T. R. Narayanan Kutty
Conditions for the preparation of stoichiometric barium zirconyl oxalate heptahydrate (BZO) have been standardized. The thermal decomposition of BZO has been investigated employing TG, DTG and DTA techniques and chemical and gas analysis. The decomposition proceeds through four steps and is not affected much by the surrounding gas atmosphere. Both dehydration and oxalate decomposition take place in two steps. The formation of a transient intermediate containing both oxalate and carbonate groups is inferred. The decomposition of oxalate groups results in a carbonate of composition Ba2Zr2O5CO3, which decomposes between 600 and 800° and yields barium zirconate. Chemical analysis, IR spectra and X-ray powder diffraction data support the identity of the intermediate as a separate entity.
Hydrated methanesulfonates Ln(CH3SO3)3nH2O (Ln=La, Ce, Pr, Nd and Yb) and Zn(CH3SO3)2nH2O were synthesized. The effect of atmosphere on thermal decomposition products of these methanesulfonates was investigated.
Thermal decomposition products in air atmosphere of these compounds were characterized by infrared spectrometry, the content
of metallic ion in thermal decomposition products were determined by complexometric titration. The results show that the thermal
decomposition atmosphere has evident effect on decomposition products of hydrated La(III), Pr(III) and Nd(III) methanesulfonates,
and no effect on that of hydrated Ce(III), Yb(III) and Zn(II) methanesulfonates.
Thermal decomposition of iron(II) and cobalt(II) hexaborates has been investigated. The methods applied to investigate the process were differential thermal analysis, derivatography, crystallooptics and x-ray study. The following iron(II) hexaborate hydrates, FeO · 3B2O3 · 7.5H2O, FeO · 3B2O3 · 5H2O, FeO · 3B2O3 · 0.5H2O; iron(III) borates, Fe2O3 · 6B2O3 and 2Fe2O3 · B2O3; cobalt(II)hexaborate hydrates CoO · 3B2O3 · 7.5H2O, CoO · 3B2O3 · 5H2O, CoO · 3B2O3 · 0.5H2O, CoO · 3B2O3 and the decomposition product 2CoO · 3B2O3 have been isolated. Hepta- and semihydrates of cobalt(II) and iron(II) hexaborates have been proved to be isomorphous. It has been established that in the case of cobalt and iron hexaborates the exothermic maximum refers to a decomposition reaction and to the formation of a borate containing a smaller proportion of boron and boric anhydride.
The thermal decomposition reactions of calcitic dolomite were investigated. Simultaneous TG/DTG/DTA were applied under non-isothermal
conditions. From the recorded curves, the activation energies, pre-exponential factors and thermodynamic parameters of activation
were calculated for the two thermal decomposition steps.