### Spectrophotometric Determination of the Average Valence of Bismuth in a $High-T_{c}$ Superconductor with o-TolidineSpectrophotometric Determination of the Average Valence of Bismuth in a $High-T_{c}$ Superconductor with o-Tolidine

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 Author Watanabe, Kunihiro ♦ Ishikawa, Makoto ♦ Ookubo, Shingo ♦ Itagaki, Masayuki Source J-STAGE Content type Text Publisher The Japan Society for Analytical Chemistry Language English
 Subject Keyword Superconductor ♦ average valence determination ♦ bismuth ♦ o-tolidine ♦ Cl2 generation method ♦ $Cl_{2}$ generation method Abstract A determination was made of the average valence of bismuth in the Bi-Sr-Ca-Cu-O superconductor using the o-tolidine spectrophotometric method to lessen the amount of sample required. The chlorine liberated by a reaction between Bi(V) and hydrochloric acid was stoichiometrically equivalent to Bi(V) in the sample. Bi(V) was determined over the range of 0.01-0.10mg based on the absorbance observed with the oxidant of o-tolidine. The total bismuth was determined by spectrophotometry after the extraction of Bi(III) with Zephiramine and iodide ions into chloroform. By a Bi(V) determination with o-tolidine, the amount of consumed sample could be decreased down 0.5mg. Although Cu(III) did not hinder the determination of Bi(V), Pb(IV) did. In the 2212 Bi-Sr-Ca-Cu-O sample having a high $T_{c}$ of 90K, the average valences of bismuth was confirmed to be from 3.12 to 3.17. ISSN 09106340 Learning Resource Type Article Publisher Date 1997-04-10 e-ISSN 13482246 Journal Analytical Sciences(analsci1985) Volume Number 13 Issue Number 2 Page Count 4 Starting Page 213 Ending Page 216