Artigo 30 – Vol. 7 N. 1


Synthesis Characterization and Thermal Behavior of Some Trivalent Lanthanide 4-Amino-Benzenesulfonates Salts. Part II (Tb, Dy, Ho, Er And Yb)

Autores
Vivian Martins Ferreira da Silva, Fabrício Rossi Marques Matias, Ronaldo Spezia Nunes, José Marques Luiz
Recebido em
 28 de Fevereiro de 2018
Aceito em
 10 de Março de 2018
Publicado em
 15 de Março de 2018
DOI
 10.18362/bjta.v7.i1.30
Páginas
Keywords
Lanthanides, Sulfanilates, 4-amino-benzenesulfonate, Thermal behavior

 

Resumo

The direct reaction between the metal carbonates and a saturated solution of 4-amino-benzenesulfonic acid were used to obtain the lanthanide 4-amino-benzenesulfonate salts. In the characterization of the compounds were used the infrared absorption spectroscopy (IRFT), X-ray diffraction (XRD), thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The samples were characterized with a stoichiometry LnL3.xH2O, where Ln = Tb3+, Dy3+, Ho3+, Er3+ and Yb3+; L = NH2C6H4SO3-, and x = 8 (Tb and Dy); 7 (Ho and Er) and 6 (Yb). The compounds are crystalline and isomorphic. The coordination of the ligand to the metal occurs through oxygen atoms of the sulfonate group, with typically ionic bonding. Dehydration occurs in a single step with stable anhydrous compound formation. Thermal decomposition occurs in several steps until the formation of the respective oxide Tb4O7, Dy2O3, Ho2O3, Er2O3 and Yb2O3. The formation of a stable intermediate, likely Ln2O2SO4, was observed. The thermal stability decreases with the increase of the atomic number of the Ln³+ ion.
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