Cobalt ammonium sulphite

Lingane and Page (56) have determined cobalt in a pyridine-chloride electrolyte by deposition into a mercury cathode at —1.20 V vs. SCE. At a pH of 6.4 or above, the average error did not exceed 0.4 mg for samples in the 10-100 mg range. Tanaka (57) deposited cobalt quantitatively on platinum cathodes from a 1.2 N ammonium hydroxide —0.2 m ammonium chloride electrolyte at —0.85 V vs SCE. Similar experiments were reported by Wilkens and Hibbs (58) who deposited cobalt from a sulphate-sulphite electrolyte held at 70-90° C on platinum electrodes at —0.80 to —0.85 V vs. SCE. 

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