Chemistry:Bismuth tribromide
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| Names | |||
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| IUPAC name bismuth bromide | |||
| Other names bismuth tribromide tribromobismuth tribromobismuthine tribromobismuthane bismuth(III) bromide | |||
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| EC Number | 
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| Properties | |||
| BiBr3 | |||
| Molar mass | 448.692 g·mol−1 | ||
| Appearance | white to light yellow or golden deliquescent crystals[1] | ||
| Density | 5.72 g/cm3 at 25 °C[1] | ||
| Melting point | 219 °C (426 °F; 492 K) [1] | ||
| Boiling point | 462 °C (864 °F; 735 K) [1] | ||
| Soluble, slow hydrolysis | |||
| Solubility | diethyl ether, THF | ||
| -147.0·10−6 cm3/mol | |||
| Thermochemistry | |||
| Std enthalpy of formation (ΔfH⦵298) | −276[1] | ||
| Hazards | |||
| Main hazards | corrosive[2] | ||
| GHS pictograms |   | ||
| GHS Signal word | Danger | ||
| H314 | |||
| P260, P264, P280, P301+330+331, P303+361+353, P304+340, P305+351+338, P310, P321, P363, P405, P501 | |||
| NFPA 704 (fire diamond) | |||
| Related compounds | |||
| Other anions | bismuth trifluoride bismuth trichloride bismuth triiodide | ||
| Other cations | nitrogen tribromide phosphorus tribromide arsenic tribromide antimony tribromide aluminium tribromide iron(III) bromide | ||
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
| Infobox references | |||
Bismuth tribromide is an inorganic compound of bismuth and bromine with the chemical formula BiBr3.
Preparation
It may be formed by the reaction of bismuth oxide and hydrobromic acid.[1]
- Bi
 2O
 3 + 6 HBr ⇌ 2 BiBr
 3 + 3 H
 2O
Bismuth tribromide can also be produced by the direct oxidation of bismuth in bromine.[1]
- 2 Bi + 3 Br
 2 → 2 BiBr
 3
Structure
Bismuth tribromide adopts two different structures in the solid state: a low-temperature polymorph α-BiBr3 that is stable below 158 °C and a high-temperature polymorph β-BiBr3 that is stable above this temperature. Both polymorphs are monoclinic, but α-BiBr3 is in space group P21/a whereas β-BiBr3 is in C2/m. α-BiBr3 consists of pyramidal molecules whereas β-BiBr3 is polymeric and adopts the AlCl3 structure. BiBr3 is the only group 15 trihalide that can adopt both molecular and polymeric structures.[3]
Reactivity
Bismuth bromide is highly water-soluble. It is a Lewis acid and accepts bromide ions to form monomeric and oligomeric anionic complexes (bromobismuthates), e.g. [BiBr6]3−, [Bi2Br10]4−, (BiBr−4)n and (BiBr2−5)n.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 558-561. ISBN 978-0-08-037941-8.
- ↑ "Sigma-Aldrich: 654981 Bismuth(III) bromide anhydrous, powder, 99.999% trace metals basis". Archived from the original on 2012-02-11. https://web.archive.org/web/20120211185950/http://www.sigmaaldrich.com/catalog/ProductDetail.do?lang=en#x7C;ALDRICH&=N5&.
- ↑ von Benda, Heike (1980). "Zur Polymorphie des Wismuttribromids". Zeitschrift für Kristallographie - Crystalline Materials 151 (1–4): 271–286. doi:10.1524/zkri.1980.151.14.271.
- ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 564-568. ISBN 978-0-08-037941-8.
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