Polonium tetraiodide

Polonium tetraiodide is a binary inorganic compound of polonium and iodine with the chemical formula. The compound forms volatile black crystals.

Synthesis
1. Action of iodine vapor on polonium metal:

2. Dissolution of polonium dioxide in hydroiodic acid:

Physical properties
The compound forms black crystals that are insoluble in water.

Chemical properties
The compound reacts with hydroiodic acid to form hexaiodopolonic acid:

It can be reduced by hydrogen sulfide to yield polonium metal. It decomposes on heating.