A Spectrophotometric Study of the Uranyl Chelate of 2-(1,8-Dihydroxy-3,6-disulfo-2-naphthylazo)-phenoxyacetic Acid

Abstract

2-(1,8-Dihydroxy-3,6-disulfo-2-naphthylazo)-phenoxyacetic acid reacts with the uranyl ion in an acidic medium to form a violet chelate. The composition of the chelate is 1 : 1 in the molar ratio. The apparent stability constants over the pH range from 3.4 to 5.2 and the formation constant of the chelate, are estimated spectrophotometrically at 25°C and an ionic strength of 0.1 by the use of KNO3. The value of the formation constant was calculated as 1.25×1010 from the apparent stability constants.