PREPARATION AND PROPERTIES OF RARE-EARTH ELEMENT COMPLEXES WITH PYRIDINE-2,6-DICARBOXYLIC ACID

The conditions of the formation of rare earth element (Y, La-Lu) dipic olinates were studied, and their quantitative compositions and solubil ities in water at 293 K were determined (10(-2) to 10(-3) mol dm-3). T he IR spectra of the hydrated complexes were recorded and their therma l decomposition in air was determined. During heating the hydrated dip icolinates Ln2(C7H3NO4)3 . nH2O (n = 9-25) lose some or all of their w ater molecules of crystallization water in one, two or three steps; th en the anhydrous or hydrated complexes decompose either directly to th e oxides (Y, Ce, Sm-Dy, Tm-Lu) or with intermediate formation of oxoca rbonates Ln2O2CO3 (La, Pr, Nd, Ho, Er).