Exploration of the thermal decomposition of oxalates of copper and silver by experimental and computational methods

Abstract

Copper and silver oxalates have been synthesized and were characterized by IR and XRD. Thermal decomposition of the prepared oxalates has been studied experimentally using differential scanning calorimetric (DSC) and thermogravimetry (TG) and the decomposition products were characterized. Topological properties of electron density, bond orders, bond length and bond angle calculations were carried out in the light of the thermal decomposition pathway characteristic for these compounds with the help of density functional theory using LanL2DZ as basis set. All the computational studies were made using Gaussian09W simulation package. The obtained results shed some additional light on the origins of the complex pathway observed during the thermal decomposition process. Global reactive descriptors like vertical ionization potential, vertical electron affinity, electronegativity, electrophilicity, softness, hardness, etc., are calculated in order to analyze the extent of reactivity of the molecules considered. The obtained results from the experiments, support the conclusion that during the thermal decomposition process, copper oxalate decompose to Cu, Cu2O/CuO nanoparticles and CO/CO2, where as the silver oxalate decompose to Ag metal and CO2, the silver metal on exposure to air is transformed to Ag2O, which are in agreement with the theoretical analysis.