Matrix isolation of unstable lower valency states of metal cations

Abstract

5.4 M sulphuric acid glasses containing various metal sulphates have been irradiated with γ-rays at 77°K. The results show that electrons are formed which can travel at least 30 Å and on encounter with cations, Mⁿ⁺, can reduce these to M^{(n– 1)+} where Mⁿ⁺= Mn²⁺, Co²⁺, Ni²⁺, Ga³⁺, Ag⁺, Cd²⁺, In³⁺ and Tl⁺. The spectra of the isoelectronic species Ag°, Cd⁺ and In²⁺ are tentatively assigned to the common transition 5²P _{or ½}â†� 5²S_½. Relative electron trapping efficiencies for the ions Ag⁺: Cd²⁺: In³⁺ at 77°K are 1.0 : 0.54 : 0.67 respectively. In addition to electrons, oxidizing species, considered to be [graphic omitted]., are formed which have a broad absorption λ_max= 444mµ. On warming, this species decays and in glasses containing Mn²⁺, Ag⁺ and Tl⁺ there is evidence for the formation of Mn³⁺, Ag²⁺ and Tl²⁺.