Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.
|
See also:DIDYMIUM (from the Gr. &Segos, twin) , the name given. to the supposed See also:element isolated by C . G . Mosander from cerite (1839-1841) . In 1879, however, Lecoq de Boisbaudran showed that Mosander's "See also:didymium " contained samarium; while the residual " didymium," after removal of samarium, was split by Auer v . Welsbach (Monats. f . Chem'ie, 1885, 6, 477) into two components (known respectively as neodymium and praseodymium) by repeated fractional See also:crystallization of the See also:double nitrate of ammonium and didymium in nitric See also:acid . Neodymium (Nd) forms the See also:chief portion of the old " didymium . " Its salts are reddish See also:violet in See also:colour, and give a characteristic absorption spectrum . It forms oxides of See also:composition Nd203 and Nd205, the latter being obtained by ignition of the nitrate (B . Brauner) . The atomic See also:weight of neodymium is 143.6 (B . Brauner, Proc .
Chem
.
See also:Soc., 1897-1898, p
.
70)
.
Praseodymium (Pr) forms oxides of composition Pr203, Pr206,xH2O (B
.
Brauner), and Pr407
.
The peroxide, Pr407, forms a dark See also: |
|
|
[back] DIDYMI, or DIDYMA (mod. Hieronta) |
[next] DIDYMUS (?3o9-?394) |
There are no comments yet for this article.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.
Links to articles and home page are encouraged.