Cerium(III) chloride

Cerium(III) chloride
Names
	IUPAC names Cerium(III) chloride; Cerium trichloride
	Other names Cerous chloride
Identifiers
CAS Number	7790-86-5 ; 18618-55-8 (heptahydrate) ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:35458 ;
ChemSpider	23038 ;
ECHA InfoCard	100.029.298
EC Number	232-227-8;
Gmelin Reference	1828
PubChem CID	24636;
UNII	TH8E3IE00V ;
CompTox Dashboard (EPA)	DTXSID1037199 ;
	InChI InChI=1S/Ce.3ClH/h;31H/q+3;;;/p-3 Key: VYLVYHXQOHJDJL-UHFFFAOYSA-K ; InChI=1/Ce.3ClH/h;31H/q+3;;;/p-3 Key: VYLVYHXQOHJDJL-DFZHHIFOAZ;
	SMILES [Cl-].[Cl-].[Cl-].[Ce+3];
Properties
Chemical formula	CeCl3
Molar mass	246.48 g/mol (anhydrous) ; 372.58 g/mol (heptahydrate)
Appearance	fine white powder
Density	3.97 g/cm3
Melting point	817 °C (1,503 °F; 1,090 K) (anhydrous) ; 90 °C (heptahydrate, decomposes)
Boiling point	1,727 °C (3,141 °F; 2,000 K)
Solubility in water	100 g/100 ml
Solubility	soluble in alcohol
Magnetic susceptibility (χ)	+2490.0·10−6 cm3/mol
Structure
Crystal structure	hexagonal (UCl3 type), hP8
Space group	P63/m, No. 176
Coordination geometry	Tricapped trigonal prismatic; (nine-coordinate)
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H315, H318, H319, H335, H400, H410
GHS precautionary statements	P261, P264, P271, P273, P280, P302+352, P304+340, P305+351+338, P310, P312, P321, P332+313, P337+313, P362, P391, P403+233, P405, P501
Flash point	Non-flammable
Related compounds
Other anions	Cerium(III) oxide; Cerium(III) fluoride; Cerium(III) bromide; Cerium(III) iodide
Other cations	Lanthanum(III) chloride; Praseodymium(III) chloride
	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

Cerium(III) chloride (CeCl₃), also known as cerous chloride or cerium trichloride, is a compound of cerium and chlorine. It is a white hygroscopic solid; it rapidly absorbs water on exposure to moist air to form a hydrate, which appears to be of variable composition,[1] though the heptahydrate CeCl₃·7H₂O is known. It is highly soluble in water, and (when anhydrous) it is soluble in ethanol and acetone.[2]

Preparation of waterless CeCl₃

Simple rapid heating of the hydrate alone may cause small amounts of hydrolysis.[3]

A useful form of anhydrous CeCl₃ can be prepared if care is taken to heat the heptahydrate gradually to 140 °C (284 °F) over many hours under vacuum.[2][4][5] This may or may not contain a little CeOCl from hydrolysis, but it is suitable for use with organolithium and Grignard reagents. Pure waterless CeCl₃ can be made by dehydration of the hydrate either by slowly heating to 400 °C (752 °F) with 4–6 equivalents of ammonium chloride under high vacuum,[3][6][7][8] or by heating with an excess of thionyl chloride for three hours.[3][9] The waterless halide may alternatively be prepared from cerium metal and hydrogen chloride.[10][11] It is usually purified by high temperature sublimation under high vacuum.

Uses

'Cerium(III) chloride' can be used as a starting point for the preparation of other cerium salts, such as the Lewis acid, cerium(III) trifluoromethanesulfonate, used for Friedel-Crafts acylations. It is also used itself as a Lewis acid, for example as a catalyst in Friedel-Crafts alkylation reactions.[12]

Luche reduction[13] of alpha, beta-unsaturated carbonyl compounds has become a popular method in organic synthesis, where CeCl₃·7H₂O is used in conjunction with sodium borohydride. For example, carvone gives only the allylic alcohol 1 and none of the saturated alcohol 2. Without CeCl₃, a mixture of 1 and 2 is formed.

Another important use in organic synthesis is for alkylation of ketones, which would otherwise form enolates if simple organolithium reagents were to be used. For example, compound 3 would be expected to simply form an enolate without CeCl₃ being present, but in the presence of CeCl₃ smooth alkylation occurs: [4]

It is reported that organolithium reagents work more effectively in this reaction than do Grignard reagents.[4]

References

Several great producers such as Alfa and Strem list their products simply as a "hydrate" with " $x$ H₂O" in the formula, but Aldrich sells a heptahydrate.
Paquette, L. A. (1999). Coates, R. M.; Denmark, S. E. (eds.). Handbook of Reagents for Organic Synthesis: Reagents, Auxiliaries and Catalysts for C-C Bond Formation. New York: Wiley. ISBN 0-471-97924-4.
Edelmann, F. T.; Poremba, P. (1997). Herrmann, W. A. (ed.). Synthetic Methods of Organometallic and Inorganic Chemistry. VI. Stuttgart: Georg Thieme Verlag. ISBN 3-13-103021-6.
Johnson, C. R.; Tait, B. D. (1987). "A cerium(III) modification of the Peterson reaction: methylenation of readily enolizable carbonyl compounds". Journal of Organic Chemistry. 52 (2): 281–283. doi:10.1021/jo00378a024. ISSN 0022-3263.
Dimitrov, Vladimir; Kostova, Kalina; Genov, Miroslav (1996). "Anhydrous cerium(III) chloride — Effect of the drying process on activity and efficiency". Tetrahedron Letters. 37 (37): 6787–6790. doi:10.1016/S0040-4039(96)01479-7.
Taylor, M. D.; Carter, P. C. (1962). "Preparation of anhydrous lanthanide halides, especially iodides". Journal of Inorganic and Nuclear Chemistry. 24 (4): 387–391. doi:10.1016/0022-1902(62)80034-7.
Kutscher, J.; Schneider, A. (1971). "Notiz zur Präparation von wasserfreien Lanthaniden-Haloge-niden, Insbesondere von Jodiden". Inorg. Nucl. Chem. Lett. 7 (9): 815. doi:10.1016/0020-1650(71)80253-2.
Greenwood, N. N.; Earnshaw, A. (1984). Chemistry of the Elements. New York: Pergamon Press. ISBN 0-08-022056-8.
Freeman, J. H.; Smith, M. L. (1958). "The preparation of anhydrous inorganic chlorides by dehydration with thionyl chloride". Journal of Inorganic and Nuclear Chemistry. 7 (3): 224–227. doi:10.1016/0022-1902(58)80073-1.
Druding, L. F.; Corbett, J. D. (1961). "Lower Oxidation States of the Lanthanides. Neodymium(II) Chloride and Iodide". Journal of the American Chemical Society. 83 (11): 2462–2467. doi:10.1021/ja01472a010. ISSN 0002-7863.
Corbett, J. D. (1973). Rev. Chim. Minerale. 10: 239. Missing or empty |title= (help)
Mine, Norioki; Fujiwara, Yuzo; Taniguchi, Hiroshi (1986). "Trichlorolanthanoid (LnCl₃)-catalyzed Friedel-Crafts alkylation reactions". Chemistry Letters. 15 (3): 357–360. doi:10.1246/cl.1986.357.
Luche, Jean-Louis; Rodriguez-Hahn, Lydia; Crabbé, Pierre (1978). "Reduction of natural enones in the presence of cerium trichloride". Journal of the Chemical Society, Chemical Communications (14): 601–602. doi:10.1039/C39780000601.

Cerium(III) chloride

Preparation of waterless CeCl3

Uses

References

Further reading

Preparation of waterless CeCl₃