Polonium

Polonium dissolves in concentrated hydrochloric acid, HCl, sulphuric acid, H₂SO₄, or concentrated nitric acid, HNO₃.

Polonium burns in air, forming polonium(IV) oxide, PoO₂:

Po(s) + O₂(g) PoO₂(s)

Polonium reacts with chlorine, Cl₂, bromine, Br₂, and iodine, I₂, forming the corresponding Po(IV) halides.

Po(s) + 2 Cl₂(g) PoCl₄(s) [yellow]
Po(s) + 2 Br₂(g) PoBr₄(s) [red]
Po(s) + 2 I₂(g) PoI₄(s) [black]