- 作者: Moustafa F. Bakr
- 作者服務機構: Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt
- 中文摘要:
The stability constants of Mg2+, Ca2+, Sr2+ and Ba2+ perchlorates with 2,4-diamino-3,5-dicyanothiophene (DADCT) have been determined at 15, 25, 35, 45 and 55 °C in 10, 20 and 30% (w/w) propanol-1-water mixtures using the conductometric technique.
The conductometric data were analysed using a model 1:1 stoichiometry by which the stability constants, Ks, and the limiting molar conductance were obtained. The plots of specific conductance versus the molar ratio [A]o/[Cn+]o suggest that the stoichiometry of metal ion complexes is of a 1:1 complex.
The stability constants tend to decrease with the atomic number as well as the ionic radii in the order Mg > Ca > Sr > Ba in 10% > 20% > 30% (w/w) propanol-1-water solvents. This trend was found to agree exactly with the Irving-Williams series for all the systems under investigation.
The thermodynamic parameters, DG°, DH° and DS°, for the complexation processes of all the complexes were evaluated and their significances were discussed. - 英文摘要: --
- 中文關鍵字: Complexation processes; Conductometric titrations; Thermodynamics.
- 英文關鍵字: Complexation processes; Conductometric titrations; Thermodynamics.