Polonide

Polonides are chemical compounds containing polonium (Po) in a negative oxidation state, typically -2. They are analogous to chalcogenides such as sulfides, selenides, and tellurides. Due to the radioactivity of polonium and the instability of many of its compounds, polonides are not well-studied.

Polonides are formed by the direct reaction of polonium with less electronegative elements, such as metals. Examples include sodium polonide (Na₂Po), potassium polonide (K₂Po), lead polonide (PbPo), and bismuth polonide (Bi₂Po₃). The ionic character of polonides increases with the electropositivity of the other element.

The properties of polonides are generally similar to those of other chalcogenides, though often more metallic due to the relatively low electronegativity of polonium. They tend to be unstable and decompose upon heating. Many polonides are semiconductors.

Because of the extreme radioactivity and toxicity of polonium, polonides are primarily of interest in academic research performed in specialized laboratories with appropriate safety precautions. They have limited practical applications.