Chemistry:Niobium(V) bromide

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Niobium(V) bromide
Nb2Br10'.png
Names
Other names
niobium pentabromide
Identifiers
3D model (JSmol)
ChemSpider
EC Number
  • 236-778-5
Properties
NbBr5
Molar mass 492.430 g/mol
Appearance wine red to black crystals
Density 4.417 g/cm3
Melting point 254 °C (489 °F; 527 K)
Boiling point 364 °C (687 °F; 637 K)
hydrolysis
Structure
orthorhombic
Hazards
Safety data sheet MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Niobium(V) bromide is the inorganic compound with the formula Nb2Br10. Its name comes from the compound's empirical formula, NbBr5.[1] It is a diamagnetic, orange solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two NbBr5 units are joined by a pair of bromide bridges. There is no bond between the Nb centres.[2] Niobium(V) chloride, niobium(V) iodide, tantalum(V) chloride, tantalum(V) bromide, and tantalum(V) iodide all share this structural motif.

Synthesis

Niobium(V) bromide can be prepared by the reaction of bromine with niobium metal at 230-250 °C in a tube furnace. It can also be produced from the more accessible oxide by metathesis using aluminium tribromide:[3]

Nb2O5 + 3.3 AlBr3 → 2 NbBr5 + 3.3 Al2O3

A challenge with the latter method is the occurrence of NbOBr3 as an impurity.

References

  1. Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford: Butterworth-Heinemann. ISBN:0-7506-3365-4.
  2. Hönle, Wolfgang; Furuseth, Sigrid; Schnering, Hans Georg von (1990). "Synthesis and Crystal Structure of Ordered, Orthorhombic α-NbBr5". Zeitschrift für Naturforschung B 45 (7): 952–956. doi:10.1515/znb-1990-0706. 
  3. G. Brauer (1963). "Niobium(V) and Tantalum(V) Bromides". in G. Brauer. Handbook of Preparative Inorganic Chemistry, 2nd Ed.. 1. NY, NY: Academic Press. pp. 1311. 

External links