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Iridium(III) chloride

Names
Other names Iridium trichloride
Identifiers
CAS Number	10025-83-9
ECHA InfoCard	100.030.028
EC Number	233-044-6
CompTox Dashboard (EPA)	DTXSID10275787
Properties
Chemical formula	IrCl3
Molar mass	298.58 g/mol (anhydrous)
Appearance	dark green solid hygroscopic
Density	5.30 g/cm, solid
Melting point	763 °C (decomp.)
Solubility in water	soluble
Structure
Crystal structure	Monoclinic, mS16
Space group	C12/m1, No. 12
Thermochemistry
Std enthalpy of formation (ΔfH298)	-257 kJ/mol
Hazards
Flash point	non-flammable
Related compounds
Other anions	Iridium(III) fluoride Iridium(III) bromide Iridium(III) iodide
Other cations	Rhodium(III) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is  ?) Infobox references

Iridium(III) chloride is the inorganic compound with the formula IrCl₃. This material is relatively rare, but the related hydrate is useful for preparing other iridium compounds. The anhydrous salt is a dark green crystalline solid. More commonly encountered is the trihydrate IrCl₃(H₂O)₃ (CAS number ).

Preparation

Iridium is separated from the other platinum group metals as crystalline ammonium hexachloroiridate(IV), (NH₄)₂ (CAS number ), which can be reduced to iridium metal in a stream of hydrogen. The spongy Ir thus produced reacts with chlorine at 300-400 °C to produce iridium(III) chloride. Like the related rhodium compound, IrCl3 adopts the structure seen for aluminium chloride.

The hydrated form is obtained by heating hydrated iridium(III) oxide with hydrochloric acid.

Uses

Hydrated iridium(III) chloride is used in the laboratory for the preparation of other iridium compounds such as Vaska's complex, trans-. Alkene complexes such as the dimeric {Ir(COD)Cl}₂ and {Ir(cycloctene)₂Cl}₂ can also be prepared by heating the trichloride with the appropriate alkene in water/alcohol mixtures. Industrially, most iridium complexes are generated from H₂IrCl₆ or (NH₄)₂IrCl₆ as these salts are the most common commercial forms of iridium chlorides, being directly obtained in the purification of iridium.

Safety

Iridium(III) chloride is not listed under Annex I of Directive 67/548/EEC, but is usually classified as irritant, R36/37/38: Irritating to eyes, respiratory system and skin. It is listed in the inventory of the Toxic Substances Control Act (TSCA).

References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
2. Vaska, L.; & DiLuzio, J. W. (1961) J. Am. Chem. Soc. 83:2784. Girolami, G.S.; Rauchfuss, T.B.; Angelici, R.J. (1999). Synthesis and Technique in Inorganic Chemistry (3rd Edn.). Sausalito:University Science Books.
3. ^ Winkhaus, G.; & Singer, H. (1966). Iridium(I)-Olefinkomplexe. Chem. Ber. 99:3610–18.
4. ^ Herde, J. L.; Lambert, J. C.; & Senoff, C. V. (1974). Cyclooctene and 1,5-Cyclooctadiene Complexes of Iridium(I). Inorg. Synth. 1974, volume 15, pages 18–20. doi:10.1002/9780470132463.ch5.

• Chlorides
• Iridium compounds
• Metal halides