Síntese, caracterização e estudo do comportamento térmico dos oxanatos de lantanídeos(III) e de ítrio(III), no estado sólido

• Ano de defesa: 2014
• Autor(a) principal: Caires, Flávio Junior [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Metais de terras raras; Analise termica; Termogravimetria; Espectroscopia de infravermelho; Sintese; Synthesis
• Link de acesso: http://hdl.handle.net/11449/122074

Solid-state LnL3∙nH2O compounds, where Ln stands for trivalent lanthanides (La to Lu) or yttrium(III) and L is oxamate (NH2COCO2 –), have been synthesized. The compounds were synthesized by addition of oxamic acid to the basic carbonate of yttrium and lanthanides in excess, under stirring and heating. The characterization of the compounds was performed using X-ray powder diffratometry, complexometry and thermoanalytical techniques such as simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) and thermogravimetry coupled to absorption spectroscopy in the region of infrared with Fourier transform (TG-FTIR). Theoretical calculations were also performed to elaborate more probable and energetically favorable structural models of the synthesized compounds and from these structures the theoretical infrared spectra were generated, with the application of methods of Functional Theory of Electron Density (DFT). The results provided information about thermal behaviour, crystallinity, stoichiometry, coordination sites and could also identify the main gaseous products released during heating of the compounds studied.