Same reaction as magnesium, calcium, aluminum. The reduction potential for gadolinium(III) is very close to the one for magnesium (from the CRC
Handbook 97th):
$$Gd^{+3}(aq)+3e^-\leftrightarrows Gd(s)~~~~-2,279~V.$$
What was the purpose, by the way? Chlorate or electroplating? |