Erbium(III) chloride

Erbium(III) chloride, is a violet solid with the formula ErCl₃. It is used in the preparation of erbium metal.

Erbium(III) chloride

Names
IUPAC name Erbium(III) chloride
Other names Erbium trichloride
Identifiers
CAS Number	10138-41-7 (anhydrous)
3D model (JSmol)	Interactive image
ChemSpider	59656
ECHA InfoCard	100.030.337
PubChem CID	66277
UNII	867J5QOF46
CompTox Dashboard (EPA)	DTXSID5064966
InChI InChI=1S/3ClH.Er/h3*1H;/q;;;+3/p-3 Key: HDGGAKOVUDZYES-UHFFFAOYSA-K InChI=1/3ClH.Er/h3*1H;/q;;;+3/p-3 Key: HDGGAKOVUDZYES-DFZHHIFOAE
SMILES Cl[Er](Cl)Cl
Properties
Chemical formula	ErCl3 (anhydrous) ErCl3·6H2O (hexahydrate)
Molar mass	273.62 g/mol (anhydrous) 381.71 g/mol (hexahydrate)
Appearance	violet hygroscopic monoclinic crystals (anhydrous) pink hygroscopic crystals (hexahydrate)
Density	4.1 g/cm^3 (anhydrous)
Melting point	776 °C (1,429 °F; 1,049 K) (anhydrous) decomposes (hexahydrate)
Boiling point	1,500 °C (2,730 °F; 1,770 K)
Solubility in water	soluble in water (anhydrous) slightly soluble in ethanol (hexahydrate)[1]
Structure[2]
Crystal structure	monoclinic
Space group	C2/m, No. 12
Lattice constant	a = 6.80 Å, b = 11.79 Å, c = 6.39 Å α = 90°, β = 110.7°, γ = 90°
Lattice volume (V)	479 Å^3
Formula units (Z)	4
Related compounds
Other anions	Erbium(III) oxide
Other cations	Holmium(III) chloride, Thulium(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

Properties

Erbium(III) chloride hydrate photographed under a fluorescent lamp

It is also found as a pink crystalline hexahydrate, CAS number [10025-75-9]. It has the interesting property that the pink colour is much more intense under light from a fluorescent lamp, as may be seen from the picture.

Anhydrous erbium(III) chloride is formed from the hexahydrate by heating under a strongly chlorinating atmosphere, such as chlorine or hydrogen chloride; otherwise erbium oxide chloride, ErOCl, is formed. An alternative preparation is to react the readily available Er₂O₃ with excess NH₄Cl to make the intermediate salt (NH₄)₃ErCl₆ plus both ammonia and water. This salt is stable with respect to hydrolysis and can be thermally decomposed under vacuum to yield anhydrous erbium(III) chloride with loss of ammonia and gaseous HCl.

It reacts with alkalis to form erbium(III) hydroxide:

ErCl₃ + 3 MOH → Er(OH)₃ + 3 MCl

Structural data

Erbium chloride forms crystals of the AlCl₃ type, with monoclinic crystals and the point group C2/m.[2]

Erbium(III) chloride hexahydrate also forms monoclinic crystals with the point group of P2/n (P2/c) - C⁴_2h. The erbium is octa-coordinated to form [Er(H₂O)₆Cl₂]⁺ ions with the isolated Cl⁻ completing the structure.[3]

Optical properties

Erbium(III) chloride solutions show a negative nonlinear absorption effect.[4]

Catalytic properties

The use of erbium(III) chloride as a catalyst has been demonstrated in the acylation of alcohols and phenols [5] and in an amine functionalisation of furfural.[6] It is a catalyst for Friedel–Crafts-type reactions, and can be used in place of cerium(III) chloride for Luche reductions.[7]

References

1. Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. pp. 4–57. ISBN 0-8493-0594-2.
2. Tempelton DH, Carter GF (1954). "The Crystal Structure of Yttrium Trichloride and Similar Compounds". J Phys Chem. 58 (11): 940–943. doi:10.1021/j150521a002.
3. Graebner EJ, Conrad GH, Duliere SF (1966). "Crystallographic data for solvated rare earth chlorides". Acta Crystallographica. 21 (6): 1012–1013. doi:10.1107/S0365110X66004420.
4. Maeda Y, Akidzuki Y, Yamada T (1998). "All-optical liquid device derived from negative nonlinear absorption effect in an erbium chloride solution". Applied Physics Letters. 73 (17): 2411–2413. doi:10.1063/1.122450.
5. Dalpozzo Renato, De Nino Antonio, Maiuolo Loredana, Oliverio Manuela, Procopio Antonio, Russo Beatrice, Tocci Amedeo (2007) Erbium(iii) Chloride: a Very Active Acylation Catalyst. Australian Journal of Chemistry 60, 75-79. doi:10.1071/CH06346
6. Synthesis of trans-4,5-Bis-dibenzylaminocyclopent-2-enone from Furfural Catalyzed by ErCl3·6H2O Mónica S. Estevão, Ricardo J. V. Martins, and Carlos A. M. Afonso Journal of Chemical Education 2017 94 (10), 1587-1589 {DOI|10.1021/acs.jchemed.6b00470}
7. Luche, Jean-Louis (2001-04-15), "Erbium(III) Chloride", in John Wiley & Sons, Ltd (ed.), Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, pp. re006, doi:10.1002/047084289x.re006, ISBN 978-0-471-93623-7