Correlations between UV-visible spectra and thermodynamics of solutions of cobalt chloride dissolved in sodium chloroaluminate melts

摘要

The UV-vis spectra of CoCl_2 dissolved in molten NaCl-AlCl_3 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 CoCl_2 had been previously determined using an EMF technique. The cell used was Co/CoCl_2-NaAlCl_4//(AgCl)_x/Ag, where the mole fraction, x, is fixed. Saturation was detected when ( delta E/ delta _x(CoCl_2))_T=0. A very sharp minimum in the solubility was found in the vicinity of the 50.00