Lanthanum hydroxide

Lanthanum(III) hydroxide
Names
	IUPAC name Lanthanum(III) hydroxide
Identifiers
CAS Number	14507-19-8;
ChemSpider	119053;
ECHA InfoCard	100.034.994
EC Number	238-510-2;
PubChem CID	5061201 wrong formula;
CompTox Dashboard (EPA)	DTXSID5065778 ;
	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
	Occupational safety and health (OHS/OSH):
Main hazards	Irritant
NFPA 704 (fire diamond)	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). (what is ?) 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]

\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]

\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]

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

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

References

^ ^a ^b 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.
^ 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.
^ Michael E. Brown, Patrick Kent Gallagher: Handbook of Thermal Analysis and Calorimetry, S. 482; ISBN 978-0-44453123-0.

External links

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[Shkolnikov2009-1] 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.

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