A Reversible Dropping Gallium Amalgam Electrode

Abstract

the positions of several anomalous spectral lines. In 1875 de Boisbaudran^ reported the actual separation of a small quantity of the element. Its physical properties were found to be very close to those predicted by Mendel eeff. The new element was named after the country in which it was discovered-Gaul (France). Gallium is dis-3 6 tributed widely, * although in very small amounts (never (6) E. Einecke, "Das Gallium," Leipzig, Verlag von Leopold Voss, 1937. more than 0 .01$ in any material) over the whole of the earth's crust. It occurs in greatest concentration associated with the ores of aluminum, zinc and germanium. Pure, solid gallium is silvery white in appearance, and, on melting at 29.75°C., is very similar to liquid mercury. Gallium has a strong tendency to wet materials such as glass. Its very great alloying ability^*^ causes (7) Atomic Energy Commission, "Liquid Metals Hand book," Washington Govt. Printing Office, 1950.

Diffusion coefficients of gallium(III) in potassium nitrate and potassium chloride supporting electrolytes

“…The diffusion coefficient values of Ga"' that we obtained are twice the value of 0.84 x cm2/s, that MacNevin and Moorhead [4] reported for Gal* in 7.5M KSCN, and half the value of 5 . 5 6~ lop6 cm2/s given by Sagadieva [17] for Ga metal in mercury.…”

“…Challenger also reported half-wave potentials for gallium in KNO3 and KCl as -1.05 V and -1.1 V (vs. SCE), respectively. MacNevin and Moorhead [4] have reported polarographic irreversibility for gallium in KN03 solutions. However, the authors observed reversibility for the gallium in 7.5 M KSCN.…”

Electrochemistry of Gallium

“…15,16) Liquid gallium can be used as dropping electrode. The overpotential measurements pertaining to the hydrogen electrode reaction (HER) on liquid gallium has been conducted in acidic and alkaline media and in the presence of alkali metal.…”

“…However, reversible gallium reduction was attained by the addition of 46) or halide 47) as well as SC 15,16) to the solution and by elevated temperature. (Fig.…”

“…MacNevin and Moorhead 15) calculated the diffusion coefficient of Ga(III) in 0.50 mM Ga(NO 3 ) 3 and 7.5 M KSCN solution from the diffusion current constant. The value was 0.84 × 10 −6 cm 2 /s with the assumption that n is 3.…”