As the fundamental studies with a view to introduce a electrochemical method into the process of refinery and recovery of palladium, the authors attempted to investigate the mechanism of electrodeposition and find the suitable electrolytic condition for the process of palladium deposition from the solutions containing N■ and Cl⁻. 
The effect of the cathode materials and cathode potentials on the current efficiency and the deposition behaviors were examined, and from these results with those of polarization curves, the conditions suitable for the electrodeposition of palladium from this system were determined.
Further, from the effects of composition of electrolyte on the electrodeposition, it was found that adhesive Pd-deposit with high current efficiecy could be obtained from the solution having N■/Pd(II) molar ratio of about 1.
Presence of N■ in excess of this ratio was found to reduce the current efficiency of Pd-deposition by participating N■ to be reduced to N■ in the cathodic reaction.
From the results of visible light absorption spectra of Pd(II)-N■-Cl⁻ system and polarization curves, the presence of intermediate complex [Pd(NO2)Cl3]²⁻ was presumed.
It was concluded from the electrochemical studies on Pd-deposition from the solutions containing Cl⁻ and N■ that the complex ion presumed here participated in electrodeposition reaction and that it was the necessary condition for good electrodeposition of palladium.