Ytterbium: historical information
In 1878 Marignac discovered a component, which he called ytterbia, in the earth then known as erbia. In 1907, Urbain separated ytterbia into two components, which he called neoytterbia and lutecia. The elements in these earths are now known as ytterbium and lutetium, respectively. These elements are identical with aldebaranium and cassiopeium, discovered independently and at about the same time by von Welsbach. The impure element was first prepared by Klemm and Bonner in 1937 who reduced ytterbium trichloride with potassium. Daane, Dennison, and Spedding prepared a purer form in 1953 from which the chemical and physical properties of the element could be determined.