Periodic table › Polonium
1. Identity and classification
Soft, ductile, silvery-white metallic solid with relatively low melting point compared to d-block transition metals
- Name and symbol
- Polonium (Polonium) · Po
- Atomic number
- 84
- Relative atomic weight / mass number
- [209]
- Group · period · block
- 16 · 6 · p
- Category
- Post-transition Metal
- State near room temperature
- Solid
- Stable isotopes
- No stable isotopes
- CAS number
- 7440-08-6
Square brackets [A] indicate a representative isotope mass number, not an average atomic weight. Neutron counts differ between isotopes.
2. Atomic structure and electron configuration
- Protons · electrons in a neutral atom
- 84 · 84
- Neutrons in reference isotope
- 125 (209Po)
- Full electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁴- Abbreviated configuration
[Xe]6s² 4f¹⁴ 5d¹⁰ 6p⁴- Electrons per shell
- 2, 8, 18, 32, 18, 6
- Listed oxidation states
- +4, +2
- Electronegativity
- 2 (Pauling)
- First ionization energy
- 812.117 kJ/mol · 8.417 eV
- Electron affinity
- 183.322 kJ/mol
- Covalent radius
- 140 pm
- van der Waals radius
- 197 pm
Configurations of superheavy elements may include theoretical predictions. Different definitions of atomic radius are not interchangeable.
3. Physical and thermal properties
- Density
- 9.32 g/cm³
- Melting point
- 527 K · 253.85 °C · 488.93 °F
- Boiling point
- 1235 K · 961.85 °C · 1763.33 °F
- Crystal structure
- Simple Cubic
- Specific heat
- 0.125 J/(g·K)
- Thermal conductivity
- 20 W/(m·K)
- Enthalpy of fusion
- 13 kJ/mol
- Enthalpy of vaporization
- 102.91 kJ/mol
- Magnetic ordering
- Paramagnetic
- Mohs hardness
- Not established
- Speed of sound
- Not established
Density and structure depend on temperature, pressure and allotrope. 25°C is a room-temperature reference, not STP. Unestablished values are not zero.
4. Chemical behavior and compounds
The listed electron configuration and oxidation states describe atomic structure; compound properties depend on bonding and composition.
Selected compounds: PoO / Po₂O₃ (Oxide) · PoClₙ (Chloride) · PoFₙ (Fluoride)
Reaction reference
Oxidation behavior depends on temperature, surface passivation and the chemical environment.
Direct reaction with water is element- and condition-dependent.
5. Isotopes
| Isotope | Status | Natural abundance | Half-life |
|---|---|---|---|
| 209Po | Radioactive | — | 124 Y |
Half-life units: s seconds, m minutes, h hours, d days, Y years. A dash means no natural-abundance value is given, not zero. Listed records are selected ground states; metastable states are distinct.
6. Discovery and occurrence
- Discovery
- 1898 CE
- Scientists associated with discovery
- Marie Curie & Pierre Curie
- Location
- France (Paris)
- Origin
- Trace Natural / Synthetic
- Listed crustal abundance
- Not established
Minerals and naming reference
Trace in Uranium pitchblende (0.1 mg per metric ton); synthesized via ²⁰⁹Bi + n
Named from scientific/historical roots associated with Polonium (Po), discovered or characterized by Marie Curie & Pierre Curie.
7. Applications
Static electricity eliminator brushes in industrial textile/film mills, compact alpha-particle heat sources (²¹⁰Po) in early lunar rovers
Detailed applications by field
- everyday
- Static electricity eliminator brushes in industrial textile/film mills, compact alpha-particle heat sources (²¹⁰Po) in early lunar rovers
- industry
- Used in post-transition metal processing, specialized alloys, and chemical manufacturing (Static electricity eliminator brushes in industrial textile/film mills, compact alpha-particle heat sources (²¹⁰Po) in early lunar rovers).
- electronics
- Applied in electronic components, semiconductors, or functional coatings where Polonium's electronic structure ([Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴) provides target conductivity.
- medicine
- Restricted to controlled nuclear medicine or fundamental radiochemical research.
- energy
- Utilized in power generation, battery materials, catalysts, or nuclear technology involving Polonium.
- aerospace
- High-performance materials, structural alloys, or space instrumentation utilizing Polonium.
- agriculture
- Not used in agriculture due to radioactivity or heavy-metal toxicity.
- science
- Spectroscopic standard, crystallography, and quantum chemistry studies of Period 6 p-block elements.
8. Biological role and safety
Hazard depends on the isotope, chemical form, dose and exposure route.
Elemental substances, ions, compounds and radioisotopes can have different health effects. This is an educational reference; laboratory work requires the material safety data sheet and trained supervision.
Biological role reference
Classified as highly radioactive / synthetic in human and biological systems.