Element Polonium, Po, Metalloid

Marie Curie nee Sklodowska, Pierre Curie's widow and co-author of his most prominent discoveries, wrote a book called "Pierre Curie" several years after her husband had been passed away, in which she particularly noticed that the pitchblende, the tar possesses 4 times higher radioactivity, than the isolated uranium, had been investigated. The method they utilized included chemical analysis of the chosen substance and measuring radioactivity of each component. Soon was found out that two fractions had increased radioactivity. So they concluded that the tar contained at least two new radioactive elements, polonium and radium. They named it Polonium after Marie's native land (Lat. Polonia - Poland).

7 natural metalloid polonium isotopes with mass numbers 210-212, 214-216 and 218 are found as members of radioactive decay series of uranium, actinouranium and thorium.

Polonium is a rare element; its crustal abundance is 2x10^-15%. Native polonium is a soft metal with silver luster, density 9.3 g/cm^-3, melting point 254°C, boiling point 1162°C. Outer electron shell configuration is 6s²6p⁴. Chemical properties are very close to those of tellurium as well as oxidation numbers: -2, +2, +4 and +6. Known oxides are PoO, PoO₂ and PoO₃ as well as hydroxide PoO(OH)₂. Zinc with polonium chloride solution yields volatile hydride PoH₂. Ions PoO₂^-4, PoO₂^-3, Po⁴⁺ and Po²⁺ exist in solutions.