Spectral and thermal studies of yttrium and heavy lanthanide 2,6-dihydroxybenzoates

The complexes of Y(III) and heavy lanthanides(III)(Gd-Lu) with 2,6-dihydroxybenzoic acid have been prepared and their IR spectra, solubilities in water and thermal decomposition have been investigated. The complexes [Ln(C7H5O4)3(H2O)4]·2H2O, when heated, lose their crystallization water in two steps and then decompose to their oxides Ln2O3 and Tb4O7 with intermediate formation of Ln(C7H5O4)H(C7H4O4). In the complexes prepared, the carboxylate groups act as monodentate and bidentate chelating ligands. The water molecules are linked in inner and outer spheres. The complexes of Y(III) and heavy lanthanides (Gd-Lu) are isostructural. (author)