Oxidation of SnF2 stannous fluoride in aqueous solutions

The rate of oxidation of SnF₂ in aqueous solutions has been studied by redox titrations and Mössbauer spectroscopy on frozen solutions versus the acidity of the solutions and versus time. Tin(II) oxidizes in aqueous solutions; however, the rate of oxidation is much slower than previously reported. Redox titrations show that the amount of tetravalent tin increases continuously with time. Oxygen dissolved in water seems to be the oxidizing species. The oxidation rate is faster in acidic solutions. Mössbauer spectroscopy on frozen solutions shows the slow formation of tetravalent tin; it also indicates that divalent tin in aqueous solutions is similar to that observed in solid SnF₂, except that one water molecule coordinates tin.