Non-metallic silver clusters in aqueous solution: stabilization and chemical reactions

Abstract

Silver ions were radiolyrically reduced in AgClO 4 solutions containing sodium poly (phosphate). In the initial stages of reduction small clusters of silver are formed as well as colloidal particles of silver metal. The clusters survive for about 1 h. They absorb at 275, 300 and 325 nm, while the metallic particles absorb at 380 nm. The clusters react with oxygen and carbon tetrachloride. Copper ions, nitrobenzene and UV illumination catalyze the transformation of the clusters into colloidal particles of metallic silver. The great reactivity of the clusters is attributed to their standard redox potential being much more negative than that of the conventional silver electrode.