Correlations Between UV-Visible Spectra and Thermodynamics of Solutions of Cobalt Chloride Dissolved in Sodium Chloroaluminate Melts

Soghomon Boghosian, Peter J. Tumidajski, M. Blander, David S. Newman
1998 ECS Proceedings Volumes  
The UV-vis spectra of C0CI2 dissolved in molten NaCl-AlCh solutions were obtained as a function of composition from slightly basic compositions to fairly acidic compositions. From these spectra it was concluded that in the basic melts the Co++ ion is tetrahedrally coordinated whereas in the acidic melts the Co++ ion is octahedrally coordinated. The solubility of C0CI2 had been previously determined using an EMF technique. The cell used was C0/C0CI2 -NaAlCl4//(AgCl)x/Ag, where the mole fraction,
more » ... X, is fixed. Saturation was detected when (5E/8%(CoC12))t = 0. A very sharp minimum in the solubility was found in the vicinity of the 50.00%NaCl-50.00%AlCl3 composition. The solubilities in acidic melts indicate that the formation constant for the CoCl+ species is very large. The cobalt spectrum in the slightly acidic melt differed from the cobalt spectra in either the basic or the very acidic melts and occurred at a composition where
doi:10.1149/199811.0637pv fatcat:6rqnhnf4pncxtbtrdagcu7joou