YTTERBIUM (NEO-YTTERBIUM) [

See also:

• SYMBOL (Gr. o-uµ(3oXov, a sign)

symbol, Yb; atomic

See also:

• WEIGHT

weight, 172.0 (0=16)]  , a metallic chemical element belonging to the rare earth group . Mixed with scandium it was discovered by Marignac in gadolinite in 1878 (see RARE EARTHS) . The oxide, Yb203, is white and forms colourless salts; the crystallized chloride, YbC13.6H20, forms colourless, deliquescent crystals; the anhydrous chloride sublimes on heating (C . Matignon, Ann. chim. plays., 1906 (8), 8, p . 440) . In 1907 G . Urbain separated ytterbium into two new elements, neo-ytterbium and lutecium (atomic weight, 174.0); and in 1908 C . A. von Welsbach published the same result, naming his elements aldebaranium and cassiopeium (on the question of priority see F . Wenzel, Zeit. anorg . Chem., 1909, 64, p . 119) .