Sinonimi: Pr | atomic number 59
Silver-white, malleable, metallic element of the lanthanide series, symbol Pr, atomic number 59, atomic weight 140.907. It occurs in nature in the minerals monzanite and bastnaesite, and its green salts are used to color glass and ceramics. It was named in 1885 by Austrian chemist Carl von Welsbach (1858–1929).
He fractionated it from dydymium (originally thought to be an element but actually a mixture of rare-earth metals consisting largely of neodymium, praseodymium, and cerium), and named it for its green salts and spectroscopic line.
A soft yellowish-white trivalent metallic element of the rare earth group; can be recovered from bastnasite or monazite by an ion-exchange process; SYN. Pr, atomic number 59.