Arsenazo III and its analogues-V Complex formation of niobium with o,o'-dihydroxyazo compounds.
A new group of reagents-the 2,7-bisazo derivatives of chromotropic acid-has been synthesized and the reaction of these compounds with niobium studied. Reaction with niobium occurs in strongly acidic medium (1-3N) and is characterized by high sensitivity ( = 30-50 x 10(3)). The functional grouping responsible for the reaction was shown to be the o,o'-dihydroxyazo group. The analytical usefulness of the reagents is determined by the presence of the electron-withdrawing substituents and the nature of the diazo coupling component. Niobium reacts in partially hydrolysed form with these reagents, to give 1:1 complexes.
Alimarin
I P
IP
Vernadsky Institute of Geochemistry and Analytical Chemistry, Academy of Sciences, Moscow, U.S.S.R.
Sawin
S B
SB
Okhanova
L A
LA