Preparation, microstructure and electrical property of (Co+CoO) mixture by thermal decomposition of [Co(NH3)6](C2O4)2·4H2O

The thermal decomposition of hexaamminecobalt(III) oxalate tetrahydrate, [Co(NH3)6](C2O4)2·4H2O, was investigated in a helium stream. The decomposition occurs in three steps. TG, IR and XRD analyses revealed that the anhydrate, the cobalt (II) oxalate, CoC2O4, and the (Co+CoO) mixture are formed in the range of 165 to 175°C, 250 to 270°C and above 330°C, respectively. SEM photographs and XRD results of the final (Co+CoO) mixture showed that the Co-component is rich near the upper part and the CoO-component is rich in the lower part. Specific surface areas and electrical resistivities of decomposition products are also reported.