112
Cn
Copernicium
285
Copernicium (Cn)
Post-Transition MetalGroup 12Period 7d-block-blockRadioactive
Copernicium is a chemical element with symbol Cn and atomic number 112. It is an extremely radioactive synthetic element that can only be created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds, but it is possible that this copernicium isotope may have a nuclear isomer with a longer half-life, 8.9 min.
Latin name: Copernicium
Atomic Number
112
Atomic Mass
285 g/mol
Phase (STP)
Solid (predicted)
Electron Config.
[Rn] 5f¹⁴ 6d¹⁰ 7s²
General
SymbolCn
Atomic Number112
Atomic Mass285 g/mol
CategoryPost-Transition Metal
Group12
Period7
Blockd-block
Electron Configuration[Rn] 5f¹⁴ 6d¹⁰ 7s²
Valence Electrons12
Colourunknown (predicted metallic)
Physical Properties
Phase (STP)Solid (predicted)
Densitypredicted ~23 g/cm3
Melting Pointpredicted ~700 K
Boiling Pointpredicted ~1400 K
Atomic Properties
Atomic Radius237 pm
Oxidation States+2, +4
Ion ChargeCn2+/Cn4+
Crystal Structure
Crystal Structurepredicted face-centered cubic
Nuclear & Hazards
RadioactiveYes
Half-life29 seconds (Cn-285)
Abundance
In Earth's Crust0%
Discovery & History
Discovery Year1996
Discovered ByGesellschaft für Schwerionenforschung (GSI), Darmstadt
Country of DiscoveryGermany
Isotopes of Copernicium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Cn-283 | — | ~4 seconds | α |
| Cn-285 | — | ~29 seconds | α |