150
R.N. Marques et al. / Thermochimica Acta 395 (2003) 145–150
resulting net heats produce only small exothermic peak
or no thermal event at all.
References
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Molina, Analyst 109 (1984) 385.
For all the compounds, the final thermal decom-
position residues were the respective oxides, Tb4O7
and Ln2O3 (Ln ¼ Gd, Dy–Lu, Y), as proven by X-ray
powder diffration analyses of these residues.
The mass losses, temperature ranges and the peak
temperatures observed for each step of the TG-DTA
curves are shown in Table 3.
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4. Conclusions
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From the TG curves and elemental analysis, a
general formula could be established for these com-
pounds in the solid state. The infrared spectroscopic
data suggest that 4-Me-BP acts as a bidentate ligand
towards trivalent lanthanides and yttrium(III).
The TG-DTA curves and X-ray powder patterns
provided previously unreported information concern-
ing crystallinity, thermal stability and thermal decom-
position of these compounds.
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The authors thank FAPESP (Proc. 97/12646-8) and
CNPq Foundations (Brazil) for financial support.
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