Polonium tetraiodide
{{Chembox
| ImageFile = Polonium tetraiodide.png
| ImageSize = 100px
| ImageAlt =
| PIN =
| OtherNames = Polonium(IV) iodide
|Section1={{Chembox Identifiers
| index1_label =
| index4_label =
| CASNo = 61716-27-6
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| EINECS =
| PubChem = 101946440
| StdInChI = 1S/4HI.Po/h4*1H;/p-4
| StdInChIKey = DHKHYWWHNZXEQM-UHFFFAOYSA-J
| SMILES = [I-].[I-].[I-].[I-].[Po]
}}
|Section2={{Chembox Properties
| Formula = {{chem|Po|I|4}}{{cite book |last1=Macintyre |first1=Jane E. |title=Dictionary of Inorganic Compounds |date=23 July 1992 |publisher=CRC Press |isbn=978-0-412-30120-9 |page=3510 |url=https://books.google.com/books?id=9eJvoNCSCRMC&dq=Polonium+tetraiodide&pg=PA3510 |access-date=2 November 2021 |language=en}}
| MolarMass = 716.6 g/mol
| Appearance = Black crystals
| Density =
| MeltingPtC = 200
| BoilingPtC =
| Solubility = Insoluble{{cite book |last1=Schweitzer |first1=George K. |last2=Pesterfield |first2=Lester L. |title=The Aqueous Chemistry of the Elements |date=14 January 2010 |publisher=Oxford University Press |isbn=978-0-19-539335-4 |page=134 |url=https://books.google.com/books?id=-oI8DwAAQBAJ&dq=Polonium(IV)+iodide+PoI4&pg=PA243 |access-date=2 November 2021 |language=en}}
}}
|Section3={{Chembox Hazards
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|Section6={{Chembox Related
| OtherCompounds = Chromium(III) sulfide
}}
}}
Polonium tetraiodide is a binary inorganic compound of polonium and iodine with the chemical formula {{chem|Po|I|4}}.{{cite book |last1=Brown |first1=Susan A. |last2=Brown |first2=Paul L. |title=The Aqueous Chemistry of Polonium and the Practical Application of its Thermochemistry |date=25 September 2019 |publisher=Elsevier |isbn=978-0-12-819309-9 |page=24 |url=https://books.google.com/books?id=eTqvDwAAQBAJ&dq=Polonium+tetraiodide&pg=PA24 |access-date=2 November 2021 |language=en}}{{cite book| first1=M.|last1=Schmidt|first2=W.|last2=Siebert|first3=K.W.|last3=Bagnall| title=The Chemistry of Sulphur, Selenium, Tellurium and Polonium: Pergamon Texts in Inorganic Chemistry|publisher=Elsevier|year=2013| pages=961–962|isbn=978-1483158655}} The compound forms volatile black crystals.
Synthesis
1. Action of iodine vapor on polonium metal:
:{{chem2 | Po + 2 I2 -> PoI4 }}
2. Dissolution of polonium dioxide in hydroiodic acid:{{cite book|author=M. Schmidt, W. Siebert, K. W. Bagnall|title=The Chemistry of Sulphur, Selenium, Tellurium and Polonium: Pergamon Texts in Inorganic Chemistry|publisher=Elsevier|date=2013|pages=961–962|isbn=978-1483158655}}
:{{chem2 |PoO2 + 4 HI -> PoI4 + 2 H2O }}
Properties
= Physical properties =
The compound forms black crystals that are insoluble in water.
=Chemical properties=
The compound reacts with hydroiodic acid to form hexaiodopolonic acid:
:{{chem2 |PoI4 + 2 HI -> H2[PoI6] }}
It can be reduced by hydrogen sulfide to yield polonium metal.{{cite journal|author=K. W. Bagnall, R. W. M. D'Eye, J. H. Freeman|title=657. The polonium halides. Part III. Polonium tetraiodide|journal=Journal of the Chemical Society (Resumed)|publisher=J. Chem. Soc.|date=1956|pages=3385–3389|doi=10.1039/JR9560003385}} It decomposes on heating.