[3] The compound is radioactive and forms black crystals.
Passing hydrogen sulfide through an acidic solution of a polonium(II) salt:[5][6] 2.
Reaction of ammonium sulfide aqueous solution with polonium(II) hydroxide: Polonium sulfide forms black solid crystals, insoluble in water, ammonium sulfide, ethanol, acetone, or toluene.
Polonium sulfide has strong reducing properties and can be oxidized by chlorine water, bromine water, sodium hypochlorite, and aqua regia.
It decomposes into elemental polonium and elemental sulfur when heated to 274.85°C in a vacuum:[7] Reacts with concentrated acids: Used in the isolation and purification of polonium.