A novel method for the determination of the oxygen content of superconducting thallium cuprates

Abstract
A novel wet chemical method based on the redox chemistry of the Cu(I)/Cu(II) couple and potentiostatic electrolyses is proposed for the determination of high metal valences in thallium cuprates. The sum of the extra oxidation states above +II for copper and +I for thallium, and thus the oxygen content of the sample, is obtained by reducing both Cu(III) and Tl(III) with CuCl. The excess of Cu(I) is electrolysed as a final analysis step. The quantitativity of the proposed method was demonstrated using YBa2Cu3Oz and Tl2O3 as reference materials for Cu(III) and Tl(III) respectively. Additionally, the oxygen content was determined in a single-phase superconducting sample with a nominal composition of Tl2Ba2CaCu2Oz.