Spectra and thermal decompositions of metal formates

Infrared spectra of a few transition metal and rare earth formates have been studied. The separation between the νasym and νsym frequencies of the carboxylate ion is not very diagnostic in understanding the nature of metal-anion bonding in the formates. The metal-oxygen stretching frequencies, however, provide some evidence for metal-formate coordination. Electronic spectra show that there is strong coordination between the formate ion and transition metal ions. Thermal decompositions of transition metal and rare earth formates have been studied employing t.g.a. and d.t.a. Rare earth formates just as the acetates first decompose to oxycarbonates and then to the sequioxides; the heavier rare earth formates decompose at lower temperatures. All the evidence seems to indicate greater covalency of the metal-anion bonds in the heavier rare earth formates.