A COMPARATIVE-STUDY ON THE THERMAL-DECOMPOSITION OF LANTHANIDE BISCITRATO CHROMATE(III) HYDRATES, LN[CR(C6H5O7)(2)]CENTER-DOT-NH(2)O

The thermal decomposition of lanthanide biscitrato chromate (III) hydr ates, [Ln(Cr(C6H5O7)(2)].nH(2)O where Ln = Pr, Nd, Dy and Ho have been carried out in static air and flowing argon atmospheres and thereby c ompared the decomposition nature with that of the lanthanum biscitrato chromate(III) dihydrate reported earlier. The precursor complexes dec ompose in four major steps. Stable oxycarbonates and chromates(V) have been isolated as intermediates. It has been found that for heavier la nthanide complexes all the decomposition steps are pushed to 'higher t emperature' ranges. Moreover, the thermal stability range of chromates (V) is much lesser compared to that of LaCrO4. Based on the observed e xperimental results a general scheme for the decomposition of lanthani de biscitrato chromate(III) hydrates is proposed.