Spectrophotometric study of the reaction of bismuth(III) with Xylenol Orange.
The reaction between bismuth(III) and Xylenol Orange (XO) has been investigated by spectrophotometry. It has been established that bismuth(III) and Xylenol Orange form complex compounds with compositions Bi(III):XO = 1:1 (up to pH 1) and Bi(III):XO = 1:2 (above pH 1) which have absorption maxima at 550 and 500 nm respectively. The formula of the 1:1 complex is [Bi(H(3)R)] whereas the 1:2 complex can take one of the following forms: [Bi(H(4)R)(2)](1-), [Bi(H(4)R)(H(3)R)](2-) and [Bi(H(3)R)(2)](3-). If the values for pK(Bi(H(3)R)) and pK(Bi(H(3)R)(2)) respectively are 9.80 +/- 0.03 and 15.53 +/- 0.03 at a constant ionic strength of 1.0.
Kantcheva
D
D
Department of Analytical Chemistry Higher Institute of Chemical Technology and Metallurgy Sofia-56, Bulgaria.
Nenova
P
P
Karadakov
B
B