Polonium dibromide
{{Chembox
| SystematicName = Polonium dibromide
|Section1={{Chembox Identifiers
| CASNo = 66794-54-5
| PubChem = 154130665
| SMILES = [Br-].[Br-].[Po+2]
| StdInChI=1S/2BrH.Po/h2*1H;/q;;+2/p-2
| StdInChIKey = XAIILPQZTLHLLU-UHFFFAOYSA-L
}}
|Section2={{Chembox Properties
| Formula = PoBr2
| MolarMass = 369.791 g mol−1
| Appearance = purple-brown crystalline solid{{Holleman&Wiberg|page=594}}
| MeltingPtC = 270
| MeltingPt_notes = (decomposes) (sublimes at 110 °C)
| SolubleOther = soluble in hydrobromic acid and ketones
}}
}}
Polonium dibromide (also known as polonium(II) bromide) is a chemical compound with the formula PoBr2. This salt is a purple-brown crystalline solid at room temperature.{{cite book |title=Advances in Inorganic Chemistry and Radiochemistry |chapter=The Chemistry of Polonium |last1=Bagnall |first1=K. W. |year=1962 |publisher=Academic Press |location=New York |isbn=978-0-12-023604-6 |pages=197–230 |accessdate=June 14, 2012 |url=https://books.google.com/books?id=8qePsa3V8GQC}} It sublimes (decomposing slightly) at 110 °C/30 μ and decomposes when melted in nitrogen gas at 270–280 °C.
Preparation
Polonium dibromide may be prepared by:
- thermal degradation of polonium tetrabromide (PoBr4) in a vacuum at 200 °C;
- dehalogenation of polonium tetrabromide by hydrogen sulfide at low temperatures (however, this does not form pure polonium dibromide, even upon heating).
Chemistry
Polonium dibromide forms purple solutions in hydrobromic acid (prepared similarly to solutions of polonium dichloride) and ketones, although the latter are rapidly oxidised to polonium(IV). Solid polonium dibromide is rapidly reduced to metallic polonium upon reaction with ammonia.
References
{{reflist}}
{{Polonium compounds}}
{{Bromides}}