Essay On TG And DTA Curves

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The TG and DTA curves obtained for the compounds (C1-C5) are shown in Figure 9. Table 4 lists the results of the thermal studies of these compounds with the initial and final temperatures (ºC), assignments of each decomposition stage based on mass calculation and DTA peaks. These assignments (Δm - Calcd.) are based on the structural fragments from the theoretical formulae of the compounds (C1–C5). This implies that the groups proposed in the right column of Table 4 are not necessarily the gaseous decomposition generated products. The X-ray powder diffractograms of the final products, obtained after the decomposition of PdO, showed the characteristic peaks of metallic powder palladium (Pd0) [30].
(Insert Figure 9)
(Insert Table 4)
The TG curve for the iminic ligand (H2L) showed that it is thermally stable
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The complex (C1) presented a mass loss of 6.98% (Calcd. 7.30%) assigned to two chloride and a mass loss of 12.70% (Calcd. 12.37%). In the complex (C2) (111-413 ºC) is assigned to the loss of one cyanate and one nitrogen-carbon fragment and two C8H8O molecules resulting in a total mass loss of 36.73% (Calcd. 35.06%), accompanied by one endothermic peak at 202 ºC. The degradation of the complexes (C3-C5) occurs by the dehalogenation of the halides and pseudohalides. Dehalogenation occurs in two stages, although well-defined plateaus are not achieved. The first stage occurs between 108-260 °C, 123-246 °C and 105-469 °C, respectively, corresponding to the loss of one thiocyanate, one bromide and two iodides (found mass loss: 4.00, 5.05 and 17.15%, calc 4.32, 5.58 and 18.00%, respectively). The loss of mass in the second step, which varied from 260-387 °C, 246-375 °C and 469-661 °C, corresponds approximately to the release, respectively, of the three thiocyanates, three bromides and two iodides (found mass loss: 12.68, 15.15 and 17.15 %, calc.12.96, 13.55, 18.18%,

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