Copernicium (Cn)

Copernicium (symbol Cn) is the chemical element with atomic number 112: a superheavy element whose properties are still unknown, radioactive, made artificially, with an atomic mass of 285 u. Discovered in 1996 (Sigurd Hofmann et al. (GSI)).

Copernicium, named after the astronomer Nicolaus Copernicus, was created at GSI in Darmstadt in 1996. Sitting below mercury, it is one of the few superheavy elements whose chemistry has been studied a little: it turned out to be highly volatile. Recent calculations suggest it could be liquid at room temperature. Its most stable known isotope, copernicium-285, lives about half a minute.

Key facts

Atomic number: 112
Symbol: Cn
French name: Copernicium
Atomic mass: 285 u
Molar mass: [285] g/mol
Family: Unknown properties
Position: period 7, group 12, d-block
State at 0 °C: Unknown
First ionization energy: 1,155 kJ/mol
Electron configuration: [Rn] 5f¹⁴ 6d¹⁰ 7s²
Radioactive: yes
Discovery: 1996, Sigurd Hofmann et al. (GSI)

Origin of the name

In honor of the astronomer Nicolaus Copernicus.

What does copernicium look like?

Never observed in visible amounts. Depending on the model, it could be a liquid or a highly volatile solid, on the borderline between a metal and a noble gas.

Where is copernicium found?

Absent from nature.

How is copernicium produced?

GSI obtained it by bombarding a lead-208 target with zinc-70 ions. Dubna produces heavier isotopes, such as copernicium-283, by bombarding uranium-238 with calcium-48, or through the decay of flerovium.

Top producers

Germany (GSI Darmstadt)
Russia (Dubna)
Japan (RIKEN)

What is copernicium used for?

Basic research only
Testing relativistic effects on chemistry

In everyday life

None — it exists only for moments in the lab

Role in living things

No biological role.

Hazards of copernicium

Radioactive, but produced atom by atom: no practical danger.

Cosmic origin

Human-made: Does not exist (or barely) in nature: synthesized in a reactor or accelerator.

History of copernicium

On February 9, 1996, Sigurd Hofmann's team at GSI detected element 112. One of the two published decay chains later turned out to have been fabricated, without undermining the discovery, which was confirmed by other atoms. The name copernicium was announced on February 19, 2010, the anniversary of Copernicus's birth.

Did you know?

The symbol first proposed, “Cp,” was rejected because it had once been used for cassiopeium, an old name for lutetium; “Cn” was chosen instead.
In 2007, an experiment led by Dubna and the Paul Scherrer Institute showed, with two atoms, that it deposits on gold like a highly volatile metal.
The tribute to Copernicus is a reminder that the nucleus at the center of the atom evokes the Sun at the center of the solar system.

Isotopes of copernicium

No stable isotopes; copernicium-285 lives for half a minute, long enough to show that it behaves a bit like a noble gas.

copernicium-277: radioactive, half-life 850 µs. The element's first synthesized isotope, in 1996.
copernicium-285: radioactive, half-life 28 s. The longest-lived known; used in experiments on copernicium chemistry.

Related elements

Same family (unknown properties): Meitnerium (Mt), Darmstadtium (Ds), Roentgenium (Rg), Nihonium (Nh), Flerovium (Fl), Moscovium (Mc), Livermorium (Lv), Tennessine (Ts), Oganesson (Og).

Same column (group 12): Zinc (Zn), Cadmium (Cd), Mercury (Hg).