Rhenium(III) bromide

Rhenium(III) bromide

Names
Other names Trirhenium nonabromide Rhenium tribromide
Identifiers
CAS Number	13569-49-8  Y
3D model (JSmol)	Interactive image
ChemSpider	15750935
ECHA InfoCard	100.033.607
EC Number	236-984-5
PubChem CID	83579
CompTox Dashboard (EPA)	DTXSID8065535
InChI InChI=1S/3BrH.Re/h3*1H;/q;;;+3/p-3
SMILES Br[Re](Br)Br
Properties
Chemical formula	Re3Br9
Molar mass	425.92 g/mol
Appearance	Black lustrous solid [1]
Melting point	500 °C (932 °F; 773 K) [2] (sublimes)
Solubility in water	Reacts [1]
Solubility	Sparingly soluble in ether and acetone, reacts with methanol and ammonia [1]
Structure
Molecular shape	Trimeric
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	−164.4 kJ/mol [3]
Related compounds
Other anions	Rhenium(III) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Rhenium(III) bromide is a chemical compound with the formula Re₃Br₉. It is a black lustrous crystalline solid. This compound reacts with water to form rhenium(IV) oxide and is isostructural with rhenium(III) chloride. ^{[1] [4]}

Preparation

This compound is prepared by the reaction of rhenium metal and bromine gas at 500 °C under nitrogen: ^[2]

6Re + 9Br₂ → 2Re₃Br₉

If there is oxygen in the atmosphere, it will instead form rhenium(III) oxybromide. ^[2]

However, the most common method of producing this compound is by first reacting potassium hexabromorhenate(IV) with silver nitrate, which forms silver hexabromorhenite(IV), then this compound is heated to 600 °C to form rhenium(III) bromide. ^{[1] [3]}

K₂ReBr₆ + 2AgNO₃ → Ag₂ReBr₆ + 2KNO₃

6Ag₂ReBr₆ → 12AgBr + 3Br₂ + 2Re₃Br₉

An alternative method is a thermal decomposition of rhenium(V) bromide.

References

1. Richard J. Thompson; Ronnie E. Foster; James L. Booker; Stephen J. Lippard (1967). "Rhenium(III) Bromide". In Muetterties, Earl (ed.). Inorganic Syntheses. Vol. 10. McGraw-Hill, Inc. pp. 58–61. doi:10.1002/9780470132418.ch9. ISBN   9780470132418.
2. Harro Hagen; Adolf Sieverts (1933). "Rheniumtribromid". Zeitschrift für anorganische und allgemeine Chemie (in German). 215 (1). Verlag GmbH & Co. KGaA, Weinheim: 111–112. doi:10.1002/zaac.19332150114.
3. J. P. King; J. W. Cobble (1960). "The Thermodynamic Properties of Technetium and Rhenium Compounds. VII. Heats of Formation of Rhenium Trichloride and Rhenium Tribromide. Free Energies and Entropies". Journal of the American Chemical Society. 82 (9): 2111–2113. doi:10.1021/ja01494a005.
4. V. V. Ugarov (1971). "Electron-diffraction investigation of the structure of the Re₃Br₉ molecule". Journal of Structural Chemistry. 12 (2): 286–288. doi:10.1007/BF00739116. S2CID   100857081.