Thermodynamics of cadmium halide complex formation in acetamide — calcium nitrate tetrahydrate melt

✍ Scribed by Slobodan B. Gadẑurić; István J. Zsigrai; Ruẑica M. Nikolić

• Book ID: 104304038
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 377 KB
• Volume: 83
• Category: Article
• ISSN: 0167-7322
• DOI: 10.1016/s0167-7322(99)00074-4

✦ Synopsis

The complex formation between cadmium(II) ions and chloride and bromide ions in the melt of 0.8CH3CONH2-0.2Ca(NOa)2.4H20 has been studied at six temperatures between 30 and 80°C. The formation constants of the complexes CdX ~ and CdX2 (X=CI, Br) were determined from emf measurements by means of Ag/AgX electrodes. The thermodynamic pa-

rameters AH°, and ASm, for the stepwise complex formation CdmX~" + ,, ~-~ml~ have been estimated. The results are AH~' 1 = 4.2 kJ mo1-1, AS~I = 52.4 J K -l tool -1, AH~': = 3.3 kJ mo1-1, AS~' 2 = 40.7 J K -1 mo1-1 for the chloride complexes and AH~' 1 = -3.3 kJ mo1-1, ASh'1 = 33.0 J K -1 mol -t, AH~'2 = -2.5 kJ tool -l, AS~' 2 = 30.4 J K -1 mol -l for the bromide complexes. The parameters are compared with the literature data for the same process in dilute aqueous solutions and in some hydrated salt melts.