Polonium tetrachloride

Polonium tetrachloride (also known as polonium(IV) chloride) is a chemical compound with the formula PoCl₄. The salt is a hygroscopic bright yellow crystalline solid at room temperature. Above 200 °C, it tends to decompose into polonium dichloride and excess chlorine, similar to selenium tetrachloride and tellurium tetrachloride.^[1]

Polonium tetrachloride

Names
Systematic IUPAC name Polonium tetrachloride
Identifiers
CAS Number	10026-02-5
3D model (JSmol)	Interactive image
ChemSpider	4896024
PubChem CID	44146666
UNII	1K48QH7W29 Y
CompTox Dashboard (EPA)	DTXSID10905310
InChI InChI=1S/4ClH.Po/h4*1H;/p-4 Key: GTPWZRGWXJYBBI-UHFFFAOYSA-J
SMILES [Cl-].[Cl-].[Cl-].[Cl-].[Po]
Properties
Chemical formula	PoCl4
Molar mass	350.79 g/mol
Appearance	Bright yellow crystalline solid[1]
Melting point	≈ 300 °C (in chlorine)[1]
Boiling point	390 °C (734 °F; 663 K)
Solubility in water	soluble,[vague] but rather slow hydrolysis
Solubility	very soluble in hydrochloric acid and thionyl chloride, moderately soluble in ethanol and acetone, decomposes in dilute nitric acid
Related compounds
Other anions	Polonium tetrafluoride Polonium tetrabromide Polonium tetraiodide
Other cations	Selenium tetrachloride Tellurium tetrachloride
Related compounds	Polonium dichloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Structure

Polonium tetrachloride is either monoclinic or triclinic.

Appearance

Polonium tetrachloride is bright yellow at room temperature. At its melting point (300 °C), it becomes straw yellow, and at its boiling point (390 °C), it becomes scarlet. Its vapours are purple-brown until 500 °C, when they turn blue-green.^[1]

Preparation

Polonium tetrachloride may be prepared by:

• halogenation of polonium dioxide with dry hydrogen chloride, gaseous thionyl chloride, or phosphorus pentachloride;^[1]
• dissolving of polonium metal in hydrochloric acid;
• heating polonium dioxide to 200 °C in carbon tetrachloride vapour;
• reaction of polonium metal with dry chlorine gas in 200 °C.

Chemistry

Polonium tetrachloride forms a complex with two moles of tributyl phosphate.

Like selenium tetrachloride and tellurium tetrachloride, polonium tetrachloride forms PoCl⁻
₅ and PoCl²⁻
₆ halogen complexes.^[1]

References

1. Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, p. 594, ISBN 0-12-352651-5