DIETILENTRIAMINPENTAACETATOBISMUTAȚI(III) DE LANTANIDE(III) ÎN CALITATE DE PRECURSORI PENTRU OXIZI HETEROMETALICI

Nelea POPA Universitatea de Stat din Moldova

Abstract

LANTHANIDE(III) DIETHYLENETRIAMINEPENTAACETATOBISMUTHATES(III) AS PRECURSORS FOR HETEROMETALLIC OXIDES

The paper relates on the synthesis and investigation of Ln(III)-Bi(III) heterometallic complexes based on diethylene-triaminepentaacetate ions (dtpa5-) with the general formula LnBi(dtpa)·10H2O (Ln(III) = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb). The complexes have been used as precursors to generate BiLnO3mixed-oxides upon thermolysis. The results of IR spectroscopy revealed the presence of one single series of analogous complexes. Thermogravimetric analysis demonstrated that at 0.5oC·min-1heating rate the thermal decomposition process of the precursors ends with the formation of inorganic residues at 530-580oC, which is 100-160oC lower than the values registered at 10oC·min-1heating rate. Powder X-ray diffraction patterns of residues obtained upon thermal decomposition of the precursors de-monstrated that heating rate affects the composition of the final residue: at 0.5oC·min-1heating rate, pure anticipated BiLnO3mixed-oxides are obtained, regardless the nature of the lanthanide, while at 10oC·min-1the desired oxides are contaminated with carbonate species.

Keywords:heterometallic complexes, precursors, Lanthanide(III), Bismuth(III), diethylenetriaminepentaacetate, thermolysis, heating rate, mixed-oxide.