Didym

Didym in Mendeleev 's first draft of the periodic table (Di) with the mass number 95 (fourth column, second element from the bottom)

Didym , abbreviation Di, was regarded as a chemical element for a long time , until Per Teodor Cleve recognized it as a combination of two elements that were finally isolated as praseodymium and neodymium by Carl Auer von Welsbach in 1885 . From Didymerde also was samarium won.

In 1839/1840 Carl Gustav Mosander found in the mineral cerite next to cerium the companions lanthanum and didym ( Greek "twin [of lanthanum]").

Individual evidence

↑ Carl Auer v. Welsbach: "The decomposition of Didym in its elements", monthly journals for chemistry , 1885 , 6 (1), pp. 477–491 ( doi: 10.1007 / BF01554643 ).

Web links

Wikisource: About the new metals lanthanium and didymium accompanying the cerium, as well as about the new metals erbium and terbium occurring with the ytter earth - sources and full texts

chemistry master on lanthanide discovery

[1] Carl Auer v. Welsbach: "The decomposition of Didym in its elements", monthly journals for chemistry , 1885 , 6 (1), pp. 477–491 ( doi: 10.1007 / BF01554643 ).