* Polonium is a member of the semi-metals family:
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POLONIUM / Po / 84
A reactive, silver-gray semi-metal. All isotopes of polonium are
unstable, and it effectively doesn't occur in nature. The
longest-lived isotope is Po<209/84>, with a half-life of 138 days.
atomic weight: 209
abundance: negligible
density: 9.32 gm/cc
melting point: 254 C
boiling point: 962 C
valence: -2 2 3? <4> 6
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Polonium is used in small amounts as a radiation or thermal source. Russian agents notoriously used it as a poison.
