Chemistry:Europium(III) chloride

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Europium(III) chloride
Europium(III) chloride hexahydrate.jpg
UCl3 without caption.png
IUPAC names
Europium(III) chloride
Europium trichloride
3D model (JSmol)
EC Number
  • 233-040-4
RTECS number
  • LE7525000
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
hexagonal (UCl3 type), hP8
P63/m, No. 176
Tricapped trigonal prismatic
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).
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Infobox references

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.


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].


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.


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

Space-filling image of EuCl3.


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


  1. Meyer, G. (1989). The Ammonium Chloride Route to Anhydrous Rare Earth Chlorides-The Example of YCl3. Inorganic Syntheses. 25. pp. 146–150. doi:10.1002/9780470132562.ch35. ISBN 978-0-470-13256-2. 
  2. 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. 
  3. Taylor, M.D.; Carter, C.P. (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. 
  4. Bradley, Donald C.; Ghotra, Joginder S.; Hart, F. Alan (1973). "Low co-ordination numbers in lanthanide and actinide compounds. Part I. The preparation and characterization of tris{bis(trimethylsilyl)-amido}lanthanides". Journal of the Chemical Society, Dalton Transactions (10): 1021. doi:10.1039/DT9730001021. 
  5. Tilley, T. Don; Andersen, Richard A.; Spencer, Brock; Ruben, Helena; Zalkin, Allan; Templeton, David H. (1980). "Divalent lanthanide chemistry. Bis (pentamethylcyclopentadienyl) europium(II) and -ytterbium(II) derivatives: crystal structure of bis (pentamethylcyclopentadienyl) (tetrahydrofuran ytterbium(II) -hemitoluene at 176 K". Inorganic Chemistry 19 (10): 2999. doi:10.1021/ic50212a031. 
  6. Evans, William J.; Hughes, Laura A.; Hanusa, Timothy P. (1986). "Synthesis and x-ray crystal structure of bis(pentamethylcyclopentadienyl) complexes of samarium and europium: (C5Me5)2Sm and (C5Me5)2Eu". Organometallics 5 (7): 1285. doi:10.1021/om00138a001. 
  7. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.