Lanthanum hydroxide
Crystal structure | ||||||||||||||||
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__ La 3+ __ OH - | ||||||||||||||||
General | ||||||||||||||||
Surname | Lanthanum hydroxide | |||||||||||||||
other names |
Lanthanum (III) hydroxide |
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Ratio formula | La (OH) 3 | |||||||||||||||
Brief description |
colorless powder |
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External identifiers / databases | ||||||||||||||||
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properties | ||||||||||||||||
Molar mass | 189.93 g mol −1 | |||||||||||||||
Physical state |
firmly |
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solubility |
almost insoluble in water |
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safety instructions | ||||||||||||||||
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Lanthanum hydroxide is the hydroxide of the rare earth metal lanthanum .
presentation
Lanthanum hydroxide can be obtained by adding alkalis , such as. B. ammonia , to aqueous solutions of lanthanum salts such as lanthanum nitrate , can be prepared. This creates a gel-like precipitate that can be dried in air.
Production from lanthanum oxide by adding it to water is also possible.
properties
Lanthanum hydroxide hardly reacts with alkalis, but easily dissolves in acids. At temperatures above 330 ° C, it breaks down to lanthanum hydroxide oxide LaOOH with the release of water, and at even higher temperatures it breaks down to lanthanum oxide.
Lanthanum hydroxide crystallizes hexagonally , space group P 6 3 / m (space group no. 176) with the lattice parameters a = 6.547 Å and c = 3.854 Å. In the crystal structure, each lanthanum ion is surrounded by nine hydroxide ions in the form of a triple-capped trigonal prism.
Web links
- Yi Dong Yin, Guang Yan Hong: Synthesis and Characterization of La (OH) 3 Nanorods by Hydrothermal Microemulsion Method , in: Chinese Chemical Letters , 2005 , 16 (12), pp. 1659-1662; PDF ( Memento from January 24, 2011 in the Internet Archive ).
Individual evidence
- ↑ a b c data sheet Lanthanum (III) hydroxide from Sigma-Aldrich , accessed on May 21, 2011 ( PDF ).
- ↑ a b c E.V. Shkolnikov: Thermodynamic Characterization of the Amphoterism of Hydroxides and Oxides of Scandium Subgroup Elements in Aqueous Media , in: Russian Journal of Applied Chemistry , 2009 , 82 (2), pp. 2098-2104.
- ↑ Jiawen Ding, Yanli Wu, Weili Sun, Yongxiu Li: Preparation of La (OH) 3 and La 2 O 3 with Rod Morphology by Simple Hydration of La 2 O 3 , in: Journal of Rare Earths , 2006 August, 24 (4 ), Pp. 440-442; doi : 10.1016 / S1002-0721 (06) 60139-7 .
- ↑ Michael E. Brown, Patrick Kent Gallagher: Handbook of Thermal Analysis and Calorimetry , p. 482; ISBN 978-0-44453123-0 .
- ^ GW Beall, WO Milligan, HA Wolcott: Structural trends in the lanthanide trihydroxides. In: Journal of Inorganic and Nuclear Chemistry , 39, 1977, pp. 65-70, doi: 10.1016 / 0022-1902 (77) 80434-X .