1911 Encyclopædia Britannica/Europium

EUROPIUM, a metallic chemical element, symbol Eu, atomic weight 152.0 (O = 16). The oxide Eu₂O₃ occurs in very small quantity in the minerals of the rare earths, and was first obtained in 1896 by E, A. Demarçay from Lecoq de Boisbaudran’s samarium; G. Urbain and H. Lacombe in 1904 obtained the pure salts by fractional crystallization of the nitric acid solution with magnesium nitrate in the presence of bismuth nitrate. The salts have a faint pink colour, and show a faint absorption spectrum; the spark spectrum is brilliant and well characterized.