Europium(III) chloride

Europium(III) chloride is an inorganic compound with the formula EuCl₃. The anhydrous compound is a yellow solid. Being hygroscopic it rapidly absorbs water to form a white crystalline hexahydrate, EuCl₃·6H₂O, which is colourless. The compound is used in research.

Europium(III) chloride

Names
IUPAC names Europium(III) chloride Europium trichloride
Identifiers
CAS Number	10025-76-0 Y 13759-92-7 (hexahydrate) N
3D model (JSmol)	Interactive image
ChemSpider	23194 Y
ECHA InfoCard	100.030.025
EC Number	233-040-4
PubChem CID	24809
RTECS number	LE7525000
UNII	LP6WL6W368 N
CompTox Dashboard (EPA)	DTXSID2041965
InChI InChI=1S/3ClH.Eu/h3*1H;/q;;;+3/p-3 Y Key: NNMXSTWQJRPBJZ-UHFFFAOYSA-K Y InChI=1/3ClH.Eu/h3*1H;/q;;;+3/p-3 Key: NNMXSTWQJRPBJZ-DFZHHIFOAZ
SMILES Cl[Eu](Cl)Cl
Properties
Chemical formula	EuCl3
Molar mass	258.323 g/mol 366.41 g/mol (hexahydrate)
Melting point	632 °C (1,170 °F; 905 K) decomposes
Solubility in other solvents	Soluble
Structure
Crystal structure	hexagonal (UCl3 type), hP8
Space group	P63/m, No. 176
Coordination geometry	Tricapped trigonal prismatic (nine-coordinate)
Related compounds
Other anions	Europium(III) oxide
Other cations	Samarium(III) chloride Gadolinium(III) chloride
Related compounds	Europium dichloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Preparation

Treating Eu₂O₃ with aqueous HCl produces hydrated europium chloride (EuCl₃·6H₂O). This salt cannot be rendered anhydrous by heating. Instead one obtains an oxychloride. Anhydrous EuCl₃ is often prepared by the "ammonium chloride route," starting from either Eu₂O₃^[1][2] or hydrated europium chloride (EuCl₃·6H₂O) by heating carefully to 230 °C.^[3] These methods produce (NH₄)₂[EuCl₅]:

10 NH₄Cl + Eu₂O₃ → 2 (NH₄)₂[EuCl₅] + 6 NH₃ + 3 H₂O

EuCl₃·6H₂O + 2 NH₄Cl → (NH₄)₂[EuCl₅] + 6 H₂O

The pentachloride decomposes thermally according to the following equation:

(NH₄)₂[EuCl₅] → 2 NH₄Cl + EuCl₃

The thermolysis reaction proceeds via the intermediary of (NH₄)[Eu₂Cl₇].

Reactions

Europium(III) chloride is a precursor to other europium compounds. It can be converted to the corresponding metal bis(trimethylsilyl)amide via salt metathesis with lithium bis(trimethylsilyl)amide.^[4] The reaction is performed in THF and requires a period at reflux.

EuCl₃ + 3 LiN(SiMe₃)₂ → Eu(N(SiMe₃)₂)₃ + 3 LiCl

Eu(N(SiMe₃)₂)₃ is a starting material for the more complicated coordination complexes.

Reduction with hydrogen gas with heating gives EuCl₂. The latter has been used to prepare organometallic compounds of europium(II), such as bis(pentamethylcyclopentadienyl)europium(II) complexes.^[5][6] Europium(III) chloride can be used as a starting point for the preparation of other europium salts.

Structure

In the solid state, it crystallises in the UCl₃ motif. The Eu centres are nine-coordinate.^[7]

Space-filling image of EuCl₃.

Bibliography

• Weast, R. C., ed. (1972). Handbook of Chemistry and Physics (53rd ed.). Cleveland, Ohio: Chemical Rubber Co.