Preparation and properties of rare earth element complexes with pyridine-2,6-dicarboxylic acid

Abstract

The conditions of the formation of rare earth element (Y, La—Lu) dipicolinates were studied, and their quantitative compositions and solubilities in water at 293 K were determined (10 −2 to 10 −3 mol dm −3). The IR spectra of the hydrated complexes were recorded and their thermal decomposition in air was determined. During heating the hydrated dipicolinates Ln 2(C 7H 3NO 4) 3 · nH 2O ( n = 9–25) lose some or all of their water molecules of crystallization water in one, two or three steps; then the anhydrous or hydrated complexes decompose either directly to the oxides (Y, Ce, Sm—Dy, Tm—Lu) or with intermediate formation of oxocarbonates Ln 2O 2CO 3 (La, Pr, Nd, Ho, Er).