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]
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]