Thermal decomposition of rare earth element complexes with 3,4-dihydroxybenzoic acid in air

Abstract

The conditions of the formation of rare earth element 3,4-dihydroxybenzoates have been studied; their quantitative composition and solubilities in water at 293 K have been determined. The IR spectra and X-ray diffraction patterns of the hydrated complexes have been recorded and their thermal decomposition in air determined. During heating the hydrated complexes Ln(C 7H 5O 4) 3 · nH 2O ( n= 2, 3) lose water of crystallization in one step; then the anhydrous complexes decompose to the oxides with intermediate formation of very unstable Ln 2(C 7H 4O 4) 3, with the exception of lanthanum which also forms La 2O 2CO 3 as an intermediate.