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Article: Lanthanum
- 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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Lanthanum
melting point:
920
°
C
boiling point: 3,469
°
C
density: 6.16 g/cm
3
most common ions: La
3+
Elemental lanthanum has a ground state (electronic configuration) of [Xe
]5d6s
2
. Naturally occurring lanthanum is a mixture of two stable
isotopes
,
138
La and
139
La. The element was discovered in 1839 by Carl Gustaf Mosander in the form of the lanthanum oxide, at that time called "lanthana." The name is derived from the Greek
lanthanein
("to lie hidden"), as the element had been overlooked due to its similarity to the earlier discovered cerium.
Monazite and bastnasite are the principal lanthanum ores, in which lanthanum occurs together with other members of the
rare earth ...