Tantalum(V) bromide

Summary

Tantalum(V) bromide
Tantalum(V) bromide
Names
Other names
tantalum pentabromide
Identifiers
  • 13451-11-1 TaBr5 ☒N
  • 17786-61-7 Ta2Br10 ☒N
3D model (JSmol)
  • Interactive image
ECHA InfoCard 100.033.276 Edit this at Wikidata
EC Number
  • 236-618-4
  • 83480
  • DTXSID1065471 Edit this at Wikidata
  • InChI=1S/5BrH.Ta/h5*1H;/q;;;;;+5/p-5
  • Br[Ta](Br)(Br)(Br)Br
Properties
Ta2Br10
Molar mass 580.468 g/mol
Appearance yellow solid
Density 4.99 g/cm³, solid
Melting point 265 °C (509 °F; 538 K)
Boiling point 349 °C (660 °F; 622 K)
hydrolysis
Hazards
not listed
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

Tantalum(V) bromide is the inorganic compound with the formula Taa2Br10. Its name comes from the compound's empirical formula, TaBr5.[1] It is a diamagnetic, orange solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two TaBr5 units are joined by a pair of bromide bridges. There is no bond between the Ta centres.[2] Niobium(V) chloride, niobium(V) bromide, niobium(V) iodide, tantalum(V) chloride, and tantalum(V) iodide all share this structural motif.

Preparation and handling

The material is usually prepared by the reaction of bromine with tantalum metal (or tantalum carbide) at elevated temperatures in a tube furnace. The bromides of the early metals are sometimes preferred to the chlorides because of the relative ease of handling liquid bromine vs gaseous chlorine. Like other molecular halides, it is soluble in nonpolar solvents such as carbon tetrachloride (1.465 g/100 mL at 30 °C), but it reacts with some solvents.[3]

It can also be produced from the more accessible oxide by metathesis using aluminium tribromide:

Ta2O5 + 3.3 AlBr3 → 2 TaBr5 + 3.3 Al2O3

Carbothermal reduction of the oxide in the presence of bromine has also been employed, the byproduct being COBr2.[4]

References

  1. ^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
  2. ^ Habermehl, Katja; Pantenburg, Ingo; Meyer, Gerd (2010). "Redetermination of tantalum pentabromide, (TaBr5)2". Acta Crystallographica Section E. 66 (9): i67. doi:10.1107/S1600536810032538. PMC 3007875. PMID 21588474.
  3. ^ Nowicki, D. H.; Campbell, I. E. (1953). "Tantalum(V) Bromide". Inorganic Syntheses. 4: 130. doi:10.1002/9780470132357.ch44.
  4. ^ G. Braurer (1963). "Niobium(V) and Tantalum(V) Bromides". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. 1. NY, NY: Academic Press. p. 1311.