Electrochemical deposition and dissolution of thallium oxide (III)

The regularities of precipitation and dissolution of thallium (III) oxide were studied by using cyclic and linear voltammetry. It is established that at 1.5V potential, a peak corresponding to the process of oxidation of monovalent to trivalent thallium is observed, according to: [Tl.sup.+] [right arrow] [Tl.sup.3+] + [2e.sup.-]. Two peaks are observed in the cathode region, at 0.65V and -0.17V potential values. At E = -0.17V, the thallium oxide [Tl.sub.2][O.sub.3] dissolves, as at E = 0.65V, the intermediate products of the hydrolysis of trivalent thallium (Tl[(OH).sup.2+], Tl [(OH).sup.2+]) are probably recovered. It was found that with increase of solution pH, the dissolution processes of thallium oxide intensified, while the optimum pH value was 11, also activation energy of the electrodeposition of thallium(III) oxide were calculated. Keywords: thallium, thallium(III) oxide, electrolysis, voltammetry, precipitation, dissolution/solution.