The polarography of aqueous pertechnetate ion

Abstract

The polarographic reduction of pertechnetate in 4-0.01 M perchloric acid media takes place in two stages. The E of the more positive wave at +0.10 to -0.17 V S.C.E. is pH-dependent, E=0.06-0.106 pH. Coulometry indicates a four-electron process, TcO4-+8 H++4 e-=Tc3+. A second wave at -0.73 V appears to involve the three-electron step (III) --> (O).Technetium electrodeposits into mercury in a finely-divided form. Centrifugation of the product indicates particles of 10-5-10-6 cm diameter. A freshly-prepared technetium "amalgam" dropping-electrode showed no anodic polarographic activity in 0.1M HCl from -0.8 to +0.05 V S.C.E., indicating little solubility, or true amalgam character.