A thermometric enthalpy titration study of the silver/thiosulphate system

Abstract

A thermometric enthalpy titration study of the silver thiosulphate system in aqueous solution has revealed that in a titration of thiosulphate with Ag+, three silver/thiosulphate complex species are formed, with stoichiometries [Ag(S2O3)2]3-, [AgS2O3]- and Ag2S2O2, whereas in the reverse titration, Ag2S2O3 is the exclusive species formed. A similar titration of either freshly precipitated silver chloride or silver bromide with thiosulphate revealed that the species [Ag(S2O3)2)]3- is formed preferentially. It is apparent that the relative concentrations of Ag+ and S2O3 2- control the number and stoichiometry of silver/thiosulphate species formed in aqueous solution. © 1991.