Lanthanum hydroxide

Lanthanum(III) hydroxide

Names
IUPAC name Lanthanum(III) hydroxide
Identifiers
CAS Number	14507-19-8
ECHA InfoCard	100.034.994
EC Number	238-510-2
PubChem	5061201
InChI InChI=1S/La.3H2O/h;3*1H2
Properties
Chemical formula	La(OH)3
Molar mass	189.93 g/mol
Solubility in water	Ksp= 2.00*10^−21
Hazards
Main hazards	Irritant
R-phrases	R36/37
S-phrases	S26, S22, S37/39
NFPA 704	1 W
Flash point	Non-flammable
Related compounds
Other anions	Lanthanum(III) chloride
Other cations	Cerium(III) hydroxide Scandium(III) hydroxide Yttrium(III) hydroxide Actinium(III) hydroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Lanthanum hydroxide is La(OH)
3, a hydroxide of the rare earth element lanthanum.

Synthesis

Lanthanum hydroxide can be obtained by adding an alkali such as ammonia to aqueous solutions of lanthanum salts such as lanthanum nitrate. This produces a gel-like precipitate that can then be dried in air. ^[1]

${\displaystyle \mathrm {La(NO_{3})_{3}\ +\ 3\ NH_{4}OH\ \longrightarrow \ La(OH)_{3}\ +\ 3\ NH_{4}NO_{3}} }$

Alternatively, it can be produced by hydration reaction (addition of water) to Lanthanum oxide. ^[2]

${\displaystyle \mathrm {La_{2}O_{3}\ +\ 3\ H_{2}O\ \longrightarrow \ 2\ La(OH)_{3}} }$

Characteristics

Lanthanum hydroxide does not react much with alkaline substances, however is slightly soluble in acidic solution. ^[1] In temperatures above 330 °C it decays into Lanthanum peroxide, LaOOH, which, upon further heating, decomposes into Lanthanum oxide. ^[3]

${\displaystyle \mathrm {La(OH)_{3}\ {\xrightarrow[{-H_{2}O}]{330^{o}C}}\ LaOOH} }$

${\displaystyle \mathrm {2\ LaOOH\ {\xrightarrow[{-H_{2}O}]{\Delta }}\ La_{2}O_{3}} }$

References

1. 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), S. 2098–2104.
2. Jiawen Ding, Yanli Wu, Weili Sun, Yongxiu Li: Preparation of La(OH)₃ and La₂O₃ with Rod Morphology by Simple Hydration of La₂O₃, in: Journal of Rare Earths, 2006 August, 24 (4), S. 440-442; doi:10.1016/S1002-0721(06)60139-7.
3. Michael E. Brown, Patrick Kent Gallagher: Handbook of Thermal Analysis and Calorimetry, S. 482; ISBN 978-0-44453123-0.

External links

• "Lanthanum - Element information, properties and uses - Periodic Table". rsc.org.
• External MSDS 1
• External MSDS 2
• Lanthanum Oxide MSDS