Under lowered pressure (such as a vacuum), it decomposes into elemental polonium and oxygen at 500 °C.

Polonium dioxide darkens upon heating, and is chocolate brown at its sublimation point, 885 °C.

When heated in sulfur dioxide at 250 °C, a white compound is formed, possibly a polonium sulfite.

[6] When polonium dioxide is hydrated, polonous acid (H2PoO3), a pale yellow, voluminous precipitate, is formed.

Neoprene gloves shield radiation from polonium better than natural rubber.