Radicals scavenging by molybdates and tungstates in water-formic acid systems

The radiation reduction of polymolybdates and polytungstates in aqueous-formic acid systems has been investigated. The reductions of 6- to 5-valent compounds take place and the molybdenum and tungsten blue compounds are formed. The yields and the structures of the blue formed compounds depend on the initial concentrations of the compounds, matrix composition and dose applied. The highest measured yields (in the case of molybdates) reaching the value of 12 equivalents per 100 eV can be explained on the basis of two-electron reduction processes with participation of HC/OH/2 radicals. The efficiencies of radicals scavenging by molybdates and tungstates have been measured. (author)