Rhodium(III) iodide
Chemical compound
From Wikipedia, the free encyclopedia
Rhodium(III) iodide is an inorganic compound with the formula RhI3. It is a black solid.[1] Some rhodium(III) iodides are used as commercial catalysts.
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| Identifiers | |
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3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.035.913 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| I3Rh | |
| Molar mass | 483.61890 g·mol−1 |
| Hazards | |
| GHS labelling: | |
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| Warning | |
| H413 | |
| P273, P501 | |
| Related compounds | |
Other anions |
Rhodium(III) bromide; Rhodium(III) chloride; Rhodium(III) fluoride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
RhI3 adopts same crystal structure motif as AlCl3 and YCl3. The structure consists of cubic close-packed iodide ions and rhodium ions filling a third of the octahedral interstices, forming a layers.[2]
Preparation
Rhodium(III) iodide can be synthesised by the reaction of aqueous potassium iodide with rhodium(III) bromide.[1]
- RhBr3 + 3KI → RhI3 + 3KBr
Reactivity
Rhodium(III) iodide is only known in the anhydrous form. Unlike the other rhodium(III) halides, it does not form hydrates.[1] The related anion [RhI6]3− was previously thought not to form[1] but has since been prepared by diffusion of RhCl3·3H2O through a layer of hydroiodic acid into piperazine.[3]
Although RhI3 and [RhI6]3− remain laboratory curiosities, other rhodium(III) iodides have had a major impact technologically. They are catalysts used in the Monsanto process, which at one time was the dominant method for producing acetic acid, a commodity chemical. One intermediate in that cycle is [(CH3)Rh(CO)2I3]−.[4]