Ethylene Glycol-Modified Cobalt and Iron Oxalates As Precursors for the Synthesis of Oxides As Extended Microsized and Nanosized Objects

摘要

The reactions of ethylene glycol with iron and cobalt oxalates upon heating in air are reported. Heat treatment of mixtures of oxalate powders with ethylene glycol yields new compounds (solvates) via the replacement of the water molecules in the oxalate structure by ethylene glycol molecules: MC_2O_4 centre dot 2H_2O+HOCH_2CH_2OH=MC_2O_4(HOCH_2CH_2OH)+2H_2Oarrow up. The crystals resulting from this reaction are elongated, and their shape is inherited by their thermolysis products. Thermolysis in air yields microwhiskers and nanowhiskers of Fe_2O_3 and Co_3O_4, and thermolysis in an inert atmosphere affords Fe_3O_4 and Co whiskers. The thermolysis of FeC_2O_4(HOCH_2CH_2OH) in helium yields a new structural modification of FeC_2O_4 as an intermediate product. The resulting compounds and their thermolysis products were characterized by X-ray powder diffraction, microscopy, IR spectroscopy, and thermogravimetric and chemical analyses. The particle shape and size were determined by scanning electron microscopy.