Thermal behavior of polymeric nickel(II) oxalate complex obtained through nickel(II) nitrate/ethylene glycol reaction Scientific paper

Abstract

This paper describes the analysis of the thermal decomposition of poly­meric nickel (II) oxalate complex, a homopolynuclear coordination comp­ound having the formula [Ni(C₂O₄)(H₂O)₂]n×xnH₂O. The thermolysis was conducted in both dynamic oxidative and inert atmospheres by simultaneously applying thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA). The proposed decomposition mechanism was con­firmed using evolved gas analysis (EGA) technique via the Fourier transform infrared spectroscopy (FTIR) of the gaseous decomposition products. The solid-state decomposition products formed during heating were investigated by chem­ical analysis, FTIR, Raman spectroscopy and X-ray diffraction (XRD). The structure, morphology and properties of the final decomposition products were characterized by XRD, FTIR, energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). These analyses show that the final decomposition product in oxidative atmosphere was nickel oxide, shaped as polygonal particles with widely distributed sizes. As for the results in inert atmo­sphere, they outlined a mixture of Ni and NiO as rhombohedral particles in a 3:2 mole ratio.