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Article: Praseodymium
- Article from:
- Chemistry: Foundations and Applications
- Author:
CopyrightCOPYRIGHT 2004 The Gale Group, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Praseodymium
melting point:
935
°
C
boiling point:
3,017
°
C
density:
6.475 g/cm
3
most common ions:
Pr
3+
,
Pr
4+
In 1885 C. A. von Welsbach isolated two elements as oxides, praseodymium (the word meaning "green twin") and neodymium (meaning "new twin"), from a mixture of
lanthanide
oxides called didymia. The oxides can be transformed to fluorides by reaction with HF at 700
°
C (1,292
°
F), or with NH
4
HF
2
at 300
°
C (572
°
F). The hydrated fluorides are then dehydrated in vacuo in a current of HF gas. The
metals
praseodymium and neodymium are obtained via metallothermic reduction with calcium at approximately 1,450
°
C (2,642
°
F), or via electrolytic ...