Radiation-chemical reduction of the polyanions PW12O403- and PW11O397- in aqueous solutions: The stability of heteropoly blue and its reaction with silver ions

The radiation-chemical reduction of the heteropoly anions PW12O403- and PW1 1O397- in solutions with pH 2.0 and 4.7 containing isopropanol was examined . Intensely colored blue products of the reduction of the heteropoly anions (blues), which contain up to six additional electrons, appeared upon gamma -irradiation. Upon continued irradiation of the acidic solutions (pH 2.0), a maximum concentration of the blue was attained. Thereafter, the blue deco mposed as a result of the deep irreversible reduction of the heteropoly ani ons. The blue formed in a solution with pH 4.7 is stable to irradiation. Th e blues can reduce silver ions to result in stable silver sols.