Redox potentials and electronic absorption spectra of dilute solutions of nickel and chromium chlorides in molten alkali chlorides

✍ Scribed by M.V. Smirnov; A.M. Potapov

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 604 KB
• Volume: 39
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)85021-6

✦ Synopsis

A technique was developed and a cell was designed for registering electronic absorption spectra of dilute nickel and chromium chloride solutions in molten alkali chlorides as a function of their redox potential. Changes in the spectra were studied in detail in them melts. Equations were derived connecting their optical density with the ratio of ion concentrations lJVi(II)]/~i(I)] and [Cr(III)]/ [Cr(II)]. That enabled the conventional formal redox potentials Ni'+/Ni+ and Cr3+/Cr2+ to be calculated from experimental spectral data. E&~,,~m,~,~ and E&nn,c,rn, are shown to be shifted towards more negative values in going from NaCl to C&l. Decrease in temperature acts in the same direction. Temperature being the same, the redox potential E&,,bpNo, is more electropositive than that of E&a,,,,,,lfl).