Thermal Stability and Decomposition Behavior of Poly[ethylenediaminetetraacetato-aqua-disodium-nickel(II)] Revealed by TGA–DTA Analysis

The thermal stability of poly[ethylenediaminetetraacetato-aqua-disodium-nickel(II)] was investigated using simultaneous thermogravimetric (TGA) and differential thermal (DTA) analyses. The coordination polymer exhibited a three-stage decomposition process between 25 and 800 °C. The first stage (88.0-316.9 °C) was associated with the removal of coordinated water molecules and the initial degradation of the EDTA ligand, resulting in a 40.82% mass loss. The second stage (316.9-439.2 °C) corresponded to the decomposition of the EDTA framework and cleavage of metal-ligand bonds with a 29.62% weight loss. The final stage (441.4-753.0 °C) involved oxidation of residual organic fragments, contributing an additional 9.97% mass loss. A residual mass of 19.59% indicates the formation of thermally stable nickel-containing inorganic products. These findings demonstrate that the synthesized coordination polymer remains thermally stable up to approximately 300 °C before undergoing stepwise decomposition.Keywords: Nickel(II), EDTA, Coordination Polymer, Thermogravimetric Analysis, Thermal Stability, TGA, DTA.