Electrochemistry of Ni(II) and the Behavior of Oxide Ions in Chloroaluminate Melts.
COLORADO STATE UNIV FORT COLLINS DEPT OF CHEMISTRY
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The electrochemical behavior of NiII has been investigated in chloroaluminate melts between 145 and 210 deg C. NiII is completely soluble in acidic mixtures where the pCl is higher than 5.5 mKg scale. A well defined and behaved reduction wave is observed at 1.2 V vs an Al reference in a NaCl saturated reference compartment. When the pCl is descreased, precipitation of NiCl2 occurs, the result which has been confirmed from electrochemical and x-ray diffraction experiments. The solubility product was found. The result is in disagreement with the precipitation of Ni0 which recently proposed in the literature. As a direct consequence, the acid-base behavior of oxide ions in chloroaluminate has been reinvestigated. Precise titrations of the basic strength of oxide ions have been performed in narrow pC1 ranges. An equilibrium constant of .016m Kg was found for the general reaction in equilibrium with two orders of magnitude higher than the previously reported value.
- Physical Chemistry