thermodynamic parameters

The complex compound NiBr₂×2(CH₂)₆N₄×10H₂O was synthesized and structurally characterized using X-ray crystallography, thermogravimetric analysis, differential scanning calorimetry, and infrared spectroscopy. The complex crystallizes in a monoclinic system (P2_1/c) with an octahedral nickel coordination environment, where Ni-O bond lengths range from 2.027 to 2.058 Å. Thermal analysis confirmed stability up to 150°C, followed by dehydration, HMTA degradation at 200°C, and framework breakdown above 300°C.

The Neutral Red (NR) has been investigated as a corrosion inhibitor for carbon steel (C-steel) in 1M perchloric acid using a weight loss method and theoretical calculations based on density functional theory (DFT). The obtained results revealed that NR is an effective inhibitor and its inhibition efficiency increases with the increasing concentration to attain 89.50 % at 5•10^-3 M at 293 K. The thermodynamic parameters as enthalpy, entropy and Gibbs free energy for both dissolution and adsorption processes are calculated and discussed.