Polonium dichloride
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| Watchedfields = changed
| verifiedrevid = 431808387
| ImageFile = Polonium-dichloride-xtal-2x2x2-1955-3D-balls.png
| ImageSize =
| IUPACName =
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo = 60816-56-0
| CASNo_Ref = {{Cascite|changed|CAS}}
| PubChem = 144504549
| StdInChI=1S/2ClH.Po/h2*1H;/q;;+2/p-2
| StdInChIKey = DUSGZPHDYXXYGD-UHFFFAOYSA-L
| SMILES =Cl[Po]Cl }}
|Section2={{Chembox Properties
| Formula = {{chem2|PoCl2}}
| MolarMass = 279.91 g/mol
| Appearance = ruby-red solid{{Holleman&Wiberg|page=594}}
| MeltingPtC = 355
| MeltingPt_notes = (sublimes at 130 °C)
| BoilingPt =
| Solubility = }}
|Section3={{Chembox Structure
| CrystalStruct = orthorhombic, oP3{{cite journal|doi=10.1039/JR9550002320|title=The polonium halides. Part I. Polonium chlorides|year=1955|last1=Bagnall|first1=K. W.|last2=d'Eye|first2=R. W. M.|last3=Freeman|first3=J. H.|journal=Journal of the Chemical Society (Resumed)|pages=2320}}
| SpaceGroup = Pmmm (No 47)
| LattConst_a = 0.367 nm
| LattConst_b = 0.435 nm
| LattConst_c = 0.450 nm
}}
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Polonium dichloride is a chemical compound of the radioactive metalloid, polonium and chlorine. Its chemical formula is {{chem2|PoCl2}}. It is an ionic salt.
Structure
Polonium dichloride appears to crystallise with an orthorhombic unit cell in either the P222, Pmm2 or Pmmm space group, although this is likely a pseudo-cell. Alternatively, the true space group may be monoclinic or triclinic, with one or more cell angles close to 90°. Assuming the space group is P222, the structure exhibits distorted cubic coordination of Po as {{chem2|{PoCl8}|}} and distorted square planar coordination of Cl as {{chem2|{ClPo4}|}}.
File:Polonium-dichloride-xtal-1955-3D-Po-coordination-3D-balls.png File:Polonium-dichloride-xtal-2x2x2-1955-3D-SF.png
Preparation
{{chem2|PoCl2}} can be obtained either by halogenation of polonium metal or by dehalogenation of polonium tetrachloride, {{chem2|PoCl4}}. Methods for dehalogenating {{chem2|PoCl4}} include thermal decomposition at 300 °C, reduction of cold, slightly moist {{chem2|PoCl4}} by sulfur dioxide; and heating {{chem2|PoCl4}} in a stream of carbon monoxide or hydrogen sulfide at 150 °C.
Reactions
{{chem2|PoCl2}} dissolves in dilute hydrochloric acid to give a pink solution, which autoxidises to Po(IV). {{chem2|PoCl2}} is rapidly oxidised by hydrogen peroxide or chlorine water. Addition of potassium hydroxide to the pink solution results in a dark brown precipitate – possibly hydrated PoO or {{chem2|Po(OH)2}} – which is rapidly oxidised to Po(IV). With dilute nitric acid, {{chem2|PoCl2}} forms a dark red solution followed by a flaky white precipitate of unknown composition.
See also
References
{{reflist}}
{{Polonium compounds}}
{{Chlorides}}