Electrochemistry of tellurium(IV) in the basic aluminum chloride-1-methyl-3-ethylimidazolium chloride room temperature molten salt

The electrochemistry of Te(IV) chloride in basic aluminum chloride-1-methyl-3-ethylimidazolium chloride molten salt was investigated at a glassy carbon electrode at 30 degrees C. Absorption spectroscopy and titration experiments suggest that tellurium(IV) chloride is complexed as [TeCl6](2-) in these melts. [TeCl6](2-) can be reduced to elemental tellurium via a four-electron process. The nucleation process for the electrodeposition of Te from reduction of [TeCl6](2-) exhibits characteristics indicative of kinetic control. Elemental Te can be further reduced to a Te(-II) species which undergoes a reaction with Te(IV) to form Te. Elemental Te can also be electrodeposited from oxidation of Te(-II). This process proceeds via 3D progressive nucleation with diffusion-controlled growth. The average Stokes-Einstein products for [TeCl6](2-) and Te(-II)species are 1.7 x 10(-10) and 3.6 x 10(-10) g cm s(-2) K-1, respectively.