Thermal and spectroscopic studies of solid oxamate of light trivalent lanthanides

• Published in: Journal of thermal analysis and calorimetry 2013, Vol.111 (1), p.349-355
• Main Authors: Caires, F. J., Lima, L. S., Gomes, D. J. C., Gigante, A. C., Treu-Filho, O., Ionashiro, M.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Calorimetry; Chemistry; Chemistry and Materials Science; Coordination compounds; Dehydration (Physiology); Exact sciences and technology; Infrared spectroscopy; Inorganic Chemistry; Inorganic chemistry and origins of life; Measurement Science and Instrumentation; Oxides; Physical Chemistry; Polymer Sciences; Preparations and properties
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-012-2220-y

Solid-state LnL 3 ·1.25H 2 O compounds, where L is oxamate and Ln is light trivalent lanthanides, have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG–DSC), experimental and theoretical infrared spectroscopy, TG–DSC coupled to FTIR, elemental analysis, complexometry, and X-ray powder diffractometry were used to characterize and to study the thermal behavior of these compounds. The results led to information about the composition, dehydration, thermal stability, thermal decomposition, and gaseous products evolved during the thermal decomposition of these compounds in dynamic air atmosphere. The dehydration occurs in a single step and through a slow process. The thermal decomposition of the anhydrous compounds occur in a single (Ce), two (Pr), and three (La, Nd to Gd) steps with the formation of the respective oxides, CeO 2 , Pr 6 O 11 , and Ln 2 O 3 (Ln = La, Nd to Gd). The theoretical and experimental spectroscopic study suggests that the carboxylate group and amide carbonyl group of oxamate are coordinate to the metals in a bidentate chelating mode.