Moscovium – facts and properties
- Symbol
- Mc
- Atomic number
- 115
- Atomic mass
- 289 u
- Period
- 7
- Group
- 15
- Category
- unknown, probably metal
- Electron configuration
- [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³
- Valence electrons
- 5
- State at standard conditions
- expected to be solid
- Discovered
- 2003
Moscovium has atomic number 115 and is one of the four heaviest known elements. It is artificial and highly radioactive, stands in group 15 below bismuth and was made at Dubna together with researchers of the Lawrence Livermore National Laboratory. Almost all of its properties are only predicted. The name goes back to the Moscow region, where Dubna lies.
Position in the periodic table
Occurrence and extraction
Moscovium exists only where it is made. Each known isotope is radioactive. The longest-lived, moscovium-290, has a quoted half-life of about half a second, but the figure is uncertain because so few atoms exist.
In 2003 a team at Dubna bombarded an americium-243 target with calcium-48. This is hot fusion, as described on the flerovium page. The fused nucleus ejects neutrons, and a nucleus with 115 protons is left. The group around Yuri Oganessian and the researchers from Livermore recorded four atoms in all. Each decayed in a chain of alpha decays through nihonium and further elements, until the chain ended in fission. The result was published in 2004. A team at GSI in Darmstadt confirmed it independently in 2013, with a different set-up.
The name was fixed in 2016, after the discovery had been recognised at the end of 2015. It refers to the Moscow region, the area around the Russian capital in which the Joint Institute for Nuclear Research at Dubna lies.
Properties and reactions
Moscovium is in period 7 and group 15, below bismuth, with antimony, arsenic, phosphorus and nitrogen above. The predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p³, giving 5 valence electrons: two in the 7s and three in the 7p orbital. The atomic mass entry, 289 u, is the mass number of moscovium-289. Nobody has measured its melting point, boiling point or density.
How far a group changes from top to bottom shows in the line of predecessors here: nitrogen and phosphorus are non-metals, bismuth is a metal. Moscovium should therefore be a metal, probably solid at room temperature, with a melting point of several hundred degrees Celsius.
As with nihonium, relativistic effects matter. The 7p level splits, and of the three 7p electrons two sit deep and tight while one sits loosely. Moscovium should therefore prefer the oxidation state plus one and resemble thallium in that respect, less so bismuth with its states plus three and plus five. This too is a calculation and not a measurement. Chemical experiments are still few. In 2024 first gas-phase experiments with single moscovium atoms were published from GSI. They suggest that moscovium is less reactive than bismuth, but the number of atoms is small. The atoms are too few and decay too quickly to pose any danger.
Research and synthesis
Moscovium is researched, not applied. Its value lies in what the decay chains reveal about the structure of heavy nuclei. Each alpha decay yields the energy and lifetime of the daughter nucleus, and many chains together build a picture of where nuclei become more stable.
Particularly valuable is that the same nuclei arise by different routes. Moscovium forms directly from americium and calcium, and also as a daughter nucleus when tennessine decays. If energies and half-lives agree on both routes, that supports the assignment of the nuclei.
So moscovium remains a subject for basic research. Whether moscovium follows thallium or bismuth in its chemistry can only be settled by further experiments with more atoms.
Quick question
What is the atomic number of moscovium (Mc)?
FAQ
Where does moscovium get its name?
From the Moscow region, where the Joint Institute for Nuclear Research at Dubna lies. The first atoms were made there. It became official in 2016.
How was moscovium discovered?
A team from Dubna and Livermore bombarded americium-243 with calcium-48 and recorded four atoms with their decay chains. GSI in Darmstadt confirmed the result in 2013.
Is moscovium dangerous?
It is highly radioactive, but every atom decays within fractions of a second, and only single atoms are made. The radiation from accelerators and targets calls for protective measures, while moscovium itself hardly counts.