Periodic TablePolonium (Po)
Polonium is a metalloid with atomic number 84, in period 6 and group 16 of the periodic table. Its atomic mass is 209 u and its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴. Solid at 25 °C.
Key facts
| Atomic number | 84 |
|---|---|
| Atomic mass | 209 u |
| Category | Metalloid |
| Period | 6 |
| Group | 16 |
| Block | p |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴ |
| Electrons per shell | 2, 8, 18, 32, 18, 6 |
| Electronegativity (Pauling) | 2 |
| Oxidation states | −2, +2, +4, +5, +6common in bold |
| State at 25 °C | Solid |
| Melting point | 527 K253.85 °C |
| Boiling point | 1235 K961.85 °C |
| Density | 9.32 g/cm³ |
Atomic properties
| First ionization energy | 8.414 eV |
|---|---|
| Electron affinity | 183.3 kJ/mol |
| Atomic radius | 176 pm |
| Covalent radius | 140 pm |
| Van der Waals radius | 197 pm |
| Common ions | Po²⁺, Po⁴⁺ |
| Protons, neutrons, electrons | 84, 125, 84 |
Physical and thermal properties
| Molar volume | 22.97 cm³/mol |
|---|---|
| Heat of fusion | 13 kJ/mol |
| Heat of vaporization | 100 kJ/mol |
| Specific heat | 126 J/(kg·K) |
| Thermal conductivity | --- |
| Thermal expansion | 2.35 × 10⁻⁵ K⁻¹ |
| Mohs hardness | --- |
| Young’s modulus | --- |
| Crystal structure | Simple cubic |
| Magnetic type | --- |
Identification and history
| CAS number | 7440-08-6 |
|---|---|
| Latin name | Polonium |
| Discovered by | P. & M. Curie · 1898 |
| Named by | --- |
Natural isotopes
Polonium has no stable isotopes: every isotope is radioactive.
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
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