Iridium(III) chloride
| Iridium(III) chloride | ||
|---|---|---|
 | ||
| Other names Iridium trichloride | ||
| Identifiers | ||
| CAS number | 10025-83-9  | |
| PubChem | 82301 | |
| EC number | 233-044-6 | |
| Properties | ||
| Molecular formula | IrCl3 | |
| Molar mass | 298.58 g/mol (anhydrous) | |
| Appearance | dark green solid hygroscopic | |
| Density | 5.30 g/cm3, solid | |
| Melting point | 763 °C (decomp.) | |
| Solubility in water | insoluble (anhydrous IrCl3), soluble (hydrated derivative) | |
| Structure | ||
| Crystal structure | Monoclinic, mS16 | |
| Space group | C12/m1, No. 12 | |
| Thermochemistry | ||
| Std enthalpy of formation ΔfH |
-257 kJ/mol | |
| Hazards | ||
| EU classification | not listed | |
| Flash point | non-flammable | |
| Related compounds | ||
| Other cations | Rhodium(III) chloride | |
| Related compounds | Platinum(II) chloride | |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| 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 [14996-61-3]).
Preparation
Iridium is separated from the other platinum group metals as crystalline ammonium hexachloroiridate(IV), (NH4)2[IrCl6] (CAS number [16940-92-4]), 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.[1]
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-[IrCl(CO)(PPh3)2].[2] Alkene complexes such as the dimeric {Ir(COD)Cl}2[3],[4] and {Ir(cycloctene)2Cl}2[4][3] 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
- ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419.
- ↑ 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.
- ↑ 3.0 3.1 Winkhaus, G.; & Singer, H. (1966). Iridium(I)-Olefinkomplexe. Chem. Ber. 99:3610–18.
- ↑ 4.0 4.1 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.
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