Lanthanum hydroxide

Lanthanum(III) hydroxide
	; __ La3+ __ OH−
Names
	IUPAC name Lanthanum(III) hydroxide
Identifiers
CAS Number	14507-19-8 ;
3D model (JSmol)	Interactive image;
ChemSpider	119053;
ECHA InfoCard	100.034.994
EC Number	238-510-2;
PubChem CID	135111;
UNII	7PTY21U5YN ;
CompTox Dashboard (EPA)	DTXSID5065778 ;
	InChI InChI=1S/La.3H2O/h;3*1H2 Key: YXEUGTSPQFTXTR-UHFFFAOYSA-K;
	SMILES [OH-].[OH-].[OH-].[La+3];
Properties
Chemical formula	La(OH)3
Molar mass	189.93 g/mol
Solubility in water	Ksp= 2.00·10−21
Structure
Crystal structure	hexagonal
Space group	P63/m, No. 176
Lattice constant	a = 6.547 Å, c = 3.854 Å
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Irritant
	GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H314
Precautionary statements	P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
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.[2]

La(NO₃)₃ + 3 NH₄OH → La(OH)₃ + 3 NH₄NO₃

Alternatively, it can be produced by hydration reaction (addition of water) to lanthanum oxide.[3]

La₂O₃ + 3 H₂O → 2 La(OH)₃

Characteristics

Lanthanum hydroxide does not react much with alkaline substances, however is slightly soluble in acidic solution.[2] In temperatures above 330 °C it decomposes into lanthanum oxide hydroxide (LaOOH), which upon further heating decomposes into lanthanum oxide (La₂O₃):[4]

La(OH)₃

\mathrm {{\xrightarrow[{-H_{2}O}]{330\ ^{o}C}}\ }

LaOOH

2 LaOOH

\mathrm {{\xrightarrow[{-H_{2}O}]{\Delta }}\ }

La₂O₃

Lanthanum hydroxide crystallizes in the hexagonal crystal system. Each lanthanum ion in the crystal structure is surrounded by nine hydroxide ions in a tricapped trigonal prism.[5]

References

"C&L Inventory". echa.europa.eu.
E.V. Shkolnikov (2009). "Thermodynamic Characterization of the Amphoterism of Hydroxides and Oxides of Scandium Subgroup Elements in Aqueous Media". Russian Journal of Applied Chemistry. 82 (2): 2098–2104. doi:10.1134/S1070427209120040. S2CID 93220420.
Ding, Jiawen; Wu, Yanli; Sun, Weili; Li, Yongxiu (2006). "Preparation of La(OH)3 and La2O3 with Rod Morphology by Simple Hydration of La2O3". Journal of Rare Earths. 24 (4): 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.
Beall, G.W.; Milligan, W.O.; Wolcott, Herbert A. (1977). "Structural trends in the lanthanide trihydroxides". Journal of Inorganic and Nuclear Chemistry. 39 (1): 65–70. doi:10.1016/0022-1902(77)80434-X.

External links

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[1] "C&L Inventory". echa.europa.eu.

[Shkolnikov2009-2] E.V. Shkolnikov (2009). "Thermodynamic Characterization of the Amphoterism of Hydroxides and Oxides of Scandium Subgroup Elements in Aqueous Media". Russian Journal of Applied Chemistry. 82 (2): 2098–2104. doi:10.1134/S1070427209120040. S2CID 93220420.

[3] Ding, Jiawen; Wu, Yanli; Sun, Weili; Li, Yongxiu (2006). "Preparation of La(OH)3 and La2O3 with Rod Morphology by Simple Hydration of La2O3". Journal of Rare Earths. 24 (4): 440–442. doi:10.1016/S1002-0721(06)60139-7.

[4] Michael E. Brown, Patrick Kent Gallagher. Handbook of Thermal Analysis and Calorimetry. p. 482. ISBN 978-0-44453123-0.

[5] Beall, G.W.; Milligan, W.O.; Wolcott, Herbert A. (1977). "Structural trends in the lanthanide trihydroxides". Journal of Inorganic and Nuclear Chemistry. 39 (1): 65–70. doi:10.1016/0022-1902(77)80434-X.