Samarium(III) chloride

Samarium(III) chloride
Names


IUPAC name samarium(III) chloride
Other names samarium trichloride trichlorosamarium
Identifiers
CAS Number	10361-82-7 (anhydrous)^Y 13465-55-9 (hexahydrate)^Y
3D model (JSmol)	Interactive image
ChemSpider	55428^Y
ECHA InfoCard	100.030.712
EC Number	233-797-0
PubChem CID	10131313
UNII	5J4QGH7J16^Y 9874IU4M1V (hexahydrate)^Y
CompTox Dashboard (EPA)	DTXSID4047757
InChI InChI=1S/3ClH.Sm/h31H;/q;;;+3/p-3^Y Key: BHXBZLPMVFUQBQ-UHFFFAOYSA-K^Y InChI=1/3ClH.Sm/h31H;/q;;;+3/p-3 Key: BHXBZLPMVFUQBQ-DFZHHIFOAZ
SMILES Cl[Sm](Cl)Cl
Properties
Chemical formula	SmCl₃
Molar mass	256.76 g/mol (anhydrous) 364.80 g/mol (hexahydrate)
Appearance	pale yellow solid (anhydrous) cream-coloured solid (hexahydrate)
Density	4.46 g/cm³ (anhydrous) 2.383 g/cm³ (hexahydrate)
Melting point	682 °C (1,260 °F; 955 K)
Boiling point	decomposes
Solubility in water	92.4 g/100 mL (10 °C)
Structure
Crystal structure	hexagonal, hP8
Space group	P6₃/m, No. 176
Coordination geometry	Tricapped trigonal prismatic (nine-coordinate)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Irritant
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319
Precautionary statements	P264, P280, P302+P352, P305+P351+P338, P321, P332+P313, P337+P313, P362
Related compounds
Other anions	Samarium(III) fluoride Samarium(III) bromide Samarium(III) oxide
Other cations	Samarium(II) chloride Promethium(III) chloride Europium(III) chloride
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

Chemical compound

Samarium(III) chloride, also known as samarium trichloride, is an inorganic compound of samarium and chloride. It is a pale yellow salt that rapidly absorbs water to form a hexahydrate, SmCl₃^.6H₂O.^[1] The compound has few practical applications but is used in laboratories for research on new compounds of samarium.

Structure

Like several related chlorides of the lanthanides and actinides, SmCl₃ crystallises in the UCl₃ motif. The Sm³⁺ centres are nine-coordinate, occupying trigonal prismatic sites with additional chloride ligands occupying the three square faces.

Preparation and reactions

SmCl₃ is prepared by the "ammonium chloride" route, which involves the initial synthesis of (NH₄)₂[SmCl₅]. This material can be prepared from the common starting materials at reaction temperatures of 230 °C from samarium oxide:^[2]

10 NH₄Cl + Sm₂O₃ → 2 (NH₄)₂[SmCl₅] + 6 NH₃ + 3 H₂O

The pentachloride is then heated to 350-400 °C resulting in evolution of ammonium chloride and leaving a residue of the anhydrous trichloride:

(NH₄)₂[SmCl₅] → 2 NH₄Cl + SmCl₃

It can also be prepared from samarium metal and hydrochloric acid.^[3]^[4]

2 Sm + 6 HCl → 2 SmCl₃ + 3 H₂

Aqueous solutions of samarium(III) chloride can be prepared by dissolving metallic samarium or samarium carbonate in hydrochloric acid.

Samarium(III) chloride is a moderately strong Lewis acid, which ranks as "hard" according to the HSAB concept. Aqueous solutions of samarium chloride can be used to prepare samarium trifluoride:

SmCl₃ + 3 KF → SmF₃ + 3 KCl

Uses

Samarium(III) chloride is used for the preparation of samarium metal, which has a variety of uses, notably in magnets. Anhydrous SmCl₃ is mixed with sodium chloride or calcium chloride to give a low melting point eutectic mixture. Electrolysis of this molten salt solution gives the free metal.^[5]

In laboratory

Samarium(III) chloride can also be used as a starting point for the preparation of other samarium salts. The anhydrous chloride is used to prepare organometallic compounds of samarium, such as bis(pentamethylcyclopentadienyl)alkylsamarium(III) complexes.^[6]

References

^ F. T. Edelmann, P. Poremba (1997). W. A. Herrmann (ed.). Synthetic Methods of Organometallic and Inorganic Chemistry. Vol. 6. Stuttgart: Georg Thieme Verlag.
^ Meyer, G. (1989). "The Ammonium Chloride Route to Anhydrous Rare Earth Chlorides—The Example of Ycl ₃". The Ammonium Chloride Route to Anhydrous Rare Earth Chlorides-The Example of YCl₃. Inorganic Syntheses. Vol. 25. pp. 146–150. doi:10.1002/9780470132562.ch35. ISBN 978-0-470-13256-2.
^ L. F. Druding, J. D. Corbett (1961). "Lower Oxidation States of the Lanthanides. Neodymium(II) Chloride and Iodide". J. Am. Chem. Soc. 83 (11): 2462–2467. doi:10.1021/ja01472a010.
^ J. D. Corbett (1973). "Reduced Halides of the Rare Earth Elements". Rev. Chim. Minérale. 10: 239.
^ Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. ISBN 978-0-08-022057-4.
^ G. A. Molander, E. D. Dowdy (1999). Shu Kobayashi (ed.). Lanthanides: Chemistry and Use in Organic Synthesis. Berlin: Springer-Verlag. pp. 119–154. ISBN 3-540-64526-8.