The reduction of ruthenium (III) hexaammine by hydrogen atoms and monovalent zinc, cadmium, and nickel ions in aqueous solutions

The specific rates of reaction of H atoms, Zn⁺, Cd⁺, and Ni⁺ with Ru(NH₃)₆³⁺ were determined. The mechanism of reduction of hexaammine complexes by hydrogen atoms is discussed. It is suggested that hydrogen atoms might penetrate the ligand sphere and form a seven coordinated transition state. The redox potentials of the Zn⁺/Zn²⁺ and Cd⁺/Cd²⁺ couples are estimated as being equal to 2.0 ± 0.4 and 1.8 ± 0.4 V, respectively.