Rearrangement of the Binuclear K4Mo2Cl8 Cluster Structure in the Process of Its Oxidation in HCl Solution

Batch-type spectroscopic and continuous potentiometric titration of K4Mo2Cl8 with potassium dichromate in 1 M hydrochloric acid was carried out. Intermediate forms of molybdenum compounds in the oxidation process were determined. It was shown that the oxidation is accompanied by a rearrangement of the complex structure with the formation of trinuclear oxo- and hydroxohalide anions of molybdenum into trinuclear oxo- and hydroxohalide molybdenum anions. The standard reduction potential of the pair $$\rm{E}^o_{298}(Mo^{VI}/Mo^{IV}_3=1.003+0.032\;V$$ was determined.