Gadolinium

(Gd), chemical element, rareearth metal of transition Group IIIb of the periodic table. Silvery white and moderately ductile, the metal reacts slowly with oxygen and water. Below 17° C it is ferromagnetic and at very low temperatures, superconducting. Credit for the discovery of gadolinium is shared by J.-C.-G. de Marignac and P.-É. Lecoq de Boisbaudran. Marignac separated (1880) a new