Thermal Decomposition Reactions of Metal Oxalato Complexes in the Solid State. II. Evolved Gas Analyses of Metal Oxalato Complexes

Abstract

Abstract The thermal decomposition reactions of a number of metal oxalato complexes in the solid state were studied by an EGA method in a helium atmosphere. As regards the decomposition stage of an anhydrous complex, the complexes investigated could be divided into three groups: the complexes of Mn(III), Fe(III), Co(III), Rh(III), Cu(II), Pd(II), and Pt(II), this first group giving only CO2 as a gaseous product, decomposed by electron transfer from an oxalato ligand to a central metal ion; the complexes of Al(III) and Zn(II), this second group giving CO and CO2 in the molar ratio of 1:1, decomposed by C–O bond breaking to form a metal oxide with no change in the oxidation number of a central metal; and the complexes of V(III) and Cr(III), this third group giving CO2and a smaller amount of CO, decomposed through both the processes, electron transfer and C–O bond breaking. The subsequent decomposition reactions of the bivalent metal oxalato complexes formed upon heating the corresponding trivalent metal oxalato complexes were divided into two types: one is associated with further reduction of a central metal ion, while the other is associated with C–O bond breaking.