THERMAL DEHYDRATION AND DECOMPOSITION OF M[M(C2O4)(2)]CENTER-DOT-XH(2)O (X=3 FOR M=SR(II) AND X=6 FOR M=HG(II))

Strontium(II) bis (oxalato) strontium(II) trihydrate, Sr[Sr(C2O4)(2)]. 3H(2)O and mercury(II) bis (oxalato) mercurate(II) hexahydrate, Hg[Hg(C2O4)(2)]. 6H(2)O have been synthesized and characterized by elemental analysis, reflectance and IR spectral studies. Thermal decomposition studies (TG, DTG and DTA) in air showed SrCO3 was formed at ca. 500 degrees C through the formation of transient intermediate of a mixture of SrCO3 and SrC2O4 around 455 degrees C. Sharp phase transition from gamma-SrCO3 to beta-SrCO3 indicated by a distinct endothermic peak at 900 degrees C in DTA. Mercury(II) bis (oxalato) mercurate(II) hexahydrate showed an inclined slope followed by surprisingly steep slope in TG at 178 degrees C and finally 98.66% of weight loss at 300 degrees C. The activation energies (E) of the dehydration and decomposition steps have been calculated by Freeman and Carroll and Flynn and Wall's method and compared with the values found by DSC in nitrogen. A tentative reaction mechanism for the thermal decomposition of Sr[Sr(C2O4)(2)]. 3H(2)O has been proposed.