Polonium has more isotopes than any other element, all of which are radioactive. Polonium dissolves readily in dilute acids, but is only slightly soluble in alkalis.
Weight for weight it is about 2.5 x 1011 times as toxic as hydrocyanic acid (HCN). Polonium has been found in tobacco as a contaminant and in uranium ores.
Image adapted with permission fromProf James Marshall's (U. North Texas, USA)Walking Tour of the elements CD.
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of polonium where known.
Isolation: polonium is radioactive and excessivley rare in nature. It is made in very small qunatities through a nuclear reaction of bismuth. Neutron irradiation of209bismuth (atomic number 83) gives210polonium (atomic number 84).
209Bi +1n →210Po + e-
Metallic polonium can be fractionally distilled from the bismuth or electrodeposited onto a metal surface such as silver.
Density of solid: 9196 kg m-3
Molar volume: 22.97 cm3
Thermal conductivity: 20 (estimate) W m‑1 K‑1
Melting point: 527 [254 °C (489 °F)] K
Boiling point: 1235 [962 °C (1764 °F)] K
Enthalpy of fusion: 20.5 kJ mol-1
Atomic radius (empirical): 190 pm
Molecular single bond covalent radius: 145 (coordination number 2) ppm
van der Waals radius: 293 ppm
Pauling electronegativity: 2.0 (Pauling units)
Allred Rochow electronegativity: 1.76 (Pauling units)
Mulliken-Jaffe electronegativity: 2.48 (16.7% s orbital)
First ionisation energy: 811.8 kJ mol‑1
Second ionisation energy: 1860 kJ mol‑1
Third ionisation energy: 2630 kJ mol‑1
Universe: (no data) ppb by weight
Crustal rocks: (no data) ppb by weight
Human: (no data) ppb by weight
