Ruthenium(III) bromide

Ruthenium(III) bromide is a chemical compound of ruthenium and bromine with the formula RuBr₃. It is a dark brown solid that decomposes above 400 °C.^[2]

Ruthenium(III) bromide

Identifiers
CAS Number	14014-88-1 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	75924
ECHA InfoCard	100.034.377
EC Number	237-829-4
PubChem CID	176290
UNII	VJ7MYGN19I Y
CompTox Dashboard (EPA)	DTXSID40930716
InChI InChI=1S/3BrH.Ru/h3*1H;/q;;;+3/p-3 Key: WYRXRHOISWEUST-UHFFFAOYSA-K
SMILES Br[Ru](Br)Br [Br-].[Br-].[Br-].[Ru+3]
Properties
Chemical formula	RuBr3
Molar mass	340.782 g/mol
Structure
Crystal structure	orthorhombic[1]
Space group	Pmmn, No. 59
Coordination geometry	octahedral
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314
Precautionary statements	P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
Related compounds
Other anions	Ruthenium(III) chloride
Other cations	Rhodium(III) bromide Iron(III) bromide Molybdenum(III) bromide
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) bromide can be prepared by the reaction of ruthenium metal with bromine at high temperature and pressure (720 K and 20 bar):^[3]

2 Ru + 3 Br₂ → 2 RuBr₃

Structure

The crystal structures of ruthenium(III) bromide contain parallel (RuBr₃)_∞ columns. The compound undergoes a phase transition around 384 K (111 °C) from an ordered orthorhombic structure in space group Pnmm with alternating long and short Ru-Ru distances to a disordered hexagonal TiI₃-like structure in space group P6₃/mcm with (on average) equal Ru-Ru distances.^[1] In the disordered polymorph, the Ru-Ru distances are not believed to actually be equal but appear so due to a random distribution of two distinct column conformations. Both polymorphs consist of hexagonally close-packed bromide ions.^[4]

References

1. Hillebrecht, H.; Ludwig, T.; Thiele, G. (2004). "About Trihalides with TiI₃ Chain Structure: Proof of Pair Forming of Cations in β-RuCl₃ and RuBr₃ by Temperature Dependent Single Crystal X-ray Analyses". Zeitschrift für Anorganische und Allgemeine Chemie. 630 (13–14): 2199–2204. doi:10.1002/zaac.200400106.
2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1082-1084. ISBN 978-0-08-037941-8.
3. Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3rd ed.). Prentice Hall. p. 779. ISBN 978-0-13-175553-6.
4. Merlino, S.; Labella, L.; Marchetti, F.; Toscani, S. (2004). "Order−Disorder Transformation in RuBr₃ and MoBr₃: A Two-Dimensional Ising Model". Chem. Mater. 16 (20): 3895–3903. doi:10.1021/cm049235q.