Abstract
The electrochemical reduction of yttrium ion on a molybdenum electrode in a 
eutectic melt at 723 K was found to be almost reversible and to proceed by a one‐step three electron reaction. The diffusion coefficient D of the Y(III) ion was measured to be 
by cyclic voltammetry, 
by the rotating disk electrode method, and 
by chronopotentiometry. The D values obtained by the latter two methods are in fairly good agreement with each other. The rather low D value obtained by cyclic voltammetry might be attributed to the fact that yttrium metal can dissolve slightly in the chloride melt. The standard potential of Y(III)/Y(0) couple was determined to be 
V (vs. 
) by open‐circuit potentiometry, 
V (vs. 
) by the rotating disk electrode method and 
V (vs. 
) by chronopotentiometry. These three values are in good agreement with each other. Several types of Ni‐Y intermetallic compounds were found to be formed on a nickel electrode.