A Study of Adsorption of Some Ag⁺-complexing Agents to Silver Bromide Grains

Abstract

A study has been made on the adsorption to silver bromide grains of typical Ag⁺-complexing agents, tetramethyl thiourea (Compound 1), 3, 4-dimethyl-4-thiazoline-2-thione (2), potassium thiocyanate (3), and 3, 6-dithia-1, 8-octanediol (4), by considering their heat of adsorption, orientation on the grain surface, influence upon electric charge of the grains, and desorption of sensitizing dyes from the grain surface. The results have indicated that Compounds 1 and 2 have stronger adsorptivity to the grains than Compounds 3 and 4. It was found from XPS of these agents that sulfur atoms in Compounds 1 and 2 had larger electron density and were more available for complex formation with Ag⁺ than those in Compounds 3 and 4.