Ruthenium(III) iodide

Ruthenium(III) iodide is a chemical compound containing ruthenium and iodine with the formula RuI₃. It is a black solid.^[2]

Ruthenium(III) iodide

Names
Other names Ruthenium triiodide
Identifiers
CAS Number	715652-38-3 Y
3D model (JSmol)	Interactive image Interactive image
ECHA InfoCard	100.034.226
CompTox Dashboard (EPA)	DTXSID90930261
InChI InChI=1S/3HI.Ru/h3*1H;/q;;;+3/p-3 Key: LJZVDOUZSMHXJH-UHFFFAOYSA-K
SMILES I[Ru](I)I [I-].[I-].[I-].[Ru+3]
Properties
Chemical formula	RuI3
Density	5.25 g cm−3
Solubility in water	sparingly soluble[1]
Structure
Crystal structure	hexagonal[1]
Thermochemistry
Std molar entropy (S⦵298)	−247 J mol−1 K−1[1]
Std enthalpy of formation (ΔfH⦵298)	−159 kJ mol−1[1]
Related compounds
Other anions	Ruthenium(III) fluoride Ruthenium(III) chloride Ruthenium(III) bromide
Other cations	Iron(III) iodide Osmium(III) iodide Technetium(III) iodide Rhodium(III) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Ruthenium(III) iodide can be prepared in several ways.^[1][3]

The reaction of ruthenium tetroxide with aqueous hydroiodic acid:^[4]

RuO₄ + excess HI → RuI₃

The thermal decomposition of pentaammineruthenium(III) iodide:^[3]

Ru(NH₃)₅I₃ → RuI₃ + 5 NH₃

The salt metathesis reaction of hydrated ruthenium(III) chloride with potassium iodide in aqueous solution:^[1]

RuCl₃·xH₂O + 3 KI → RuI₃ + 3 KCl + xH₂O

Direct combination of the elements has been reported to succeed under some conditions (350 °C) but not others (500 °C and 20 atm):^[1]

2 Ru + 3 I₂ → 2 RuI₃

Structure

Ruthenium(III) iodide adopts an extended structure with octahedral coordination geometry at ruthenium.^[4] There is some doubt about the characterisation of ruthenium(III) iodide and it may be an oxohalide or a hydroxyhalide.^[1]

References

1. Seddon, Elaine A.; Seddon, Kenneth R. (1984). The Chemistry of Ruthenium. Elsevier. p. 161. ISBN 0-444-42375-3.
2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1083. ISBN 978-0-08-037941-8.
3. Cotton, Simon A. (1997). Chemistry of Precious Metals. Springer Netherlands. p. 3. ISBN 9780751404135.
4. Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3rd ed.). Prentice Hall. p. 779. ISBN 978-0-13-175553-6.