# Isotopes of moscovium

Moscovium ($_{115}$Mc) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no known stable isotopes. The first isotope to be synthesized was $^{288}$Mc in 2004. There are five known radioisotopes from $^{286}$Mc to $^{290}$Mc. The longest-lived isotope is $^{290}$Mc with a half-life of 0.65 seconds.

## List of isotopes

The isotopes undergo alpha decay into the corresponding isotope of nihonium, with half-lives increasing as neutron numbers increase.
| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope |
| $^{286}$Mc | 115 | 171 | | 20+98 −9 ms | α | $^{282}$Nh |
| $^{287}$Mc | 115 | 172 | 287.19082(48)# | 38+22 −10 ms | α | $^{283}$Nh |
| $^{288}$Mc | 115 | 173 | 288.19288(58)# | 193+15 −13 ms | α | $^{284}$Nh |
| $^{289}$Mc | 115 | 174 | 289.19397(83)# | 250+51 −35 ms | α | $^{285}$Nh |
| $^{290}$Mc | 115 | 175 | 290.19624(64)# | 650+490 −200 ms [0.84(36) s] | α | $^{286}$Nh |
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* ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
* ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
* ↑ Not directly synthesized, created as decay product of $^{294}$Ts

## Nucleosynthesis

Chronology of isotope discovery :
| Isotope | Year discovered | Discovery reaction |
| $^{286}$Mc | 2021 | $^{243}$Am($^{48}$Ca,5n) |
| $^{287}$Mc | 2003 | $^{243}$Am($^{48}$Ca,4n) |
| $^{288}$Mc | 2003 | $^{243}$Am($^{48}$Ca,3n) |
| $^{289}$Mc | 2009 | $^{249}$Bk($^{48}$Ca,4n) |
| $^{290}$Mc | 2009 | $^{249}$Bk($^{48}$Ca,3n) |

### Target-projectile combinations

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z = 115. Each entry is a combination for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.
| Target | Projectile | CN | Attempt result |
| $^{208}$Pb | $^{75}$As | $^{283}$Mc | Reaction yet to be attempted |
| $^{209}$Bi | $^{76}$Ge | $^{285}$Mc | Reaction yet to be attempted |
| $^{238}$U | $^{51}$V | $^{289}$Mc | Failure to date |
| $^{243}$Am | $^{48}$Ca | $^{291}$Mc | Successful reaction |
| $^{241}$Am | $^{48}$Ca | $^{289}$Mc | Planned reaction |
| $^{243}$Am | $^{44}$Ca | $^{287}$Mc | Reaction yet to be attempted |

### Hot fusion

Hot fusion reactions are processes that create compound nuclei at high excitation energy (~40–50 MeV, hence "hot"), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing $^{48}$Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.

#### $^{238}$U($^{51}$V,xn)$^{289−x}$Mc

There are strong indications that this reaction was performed in late 2004 as part of a uranium(IV) fluoride target test at the GSI. No reports have been published suggesting that no product atoms were detected, as anticipated by the team.

#### $^{243}$Am($^{48}$Ca,xn)$^{291−x}$Mc (x=2,3,4,5)

This reaction was first performed by the team in Dubna in July–August 2003. In two separate runs they were able to detect 3 atoms of $^{288}$Mc and a single atom of $^{287}$Mc. The reaction was studied further in June 2004 in an attempt to isolate the descendant $^{268}$Db from the $^{288}$Mc decay chain. After chemical separation of a +4/+5 fraction, 15 SF decays were measured with a lifetime consistent with $^{268}$Db. In order to prove that the decays were from dubnium-268, the team repeated the reaction in August 2005 and separated the +4 and +5 fractions and further separated the +5 fractions into tantalum-like and niobium-like ones. Five SF activities were observed, all occurring in the niobium-like fractions and none in the tantalum-like fractions, proving that the product was indeed isotopes of dubnium.
In a series of experiments between October 2010 – February 2011, scientists at the FLNR studied this reaction at a range of excitation energies. They were able to detect 21 atoms of $^{288}$Mc and one atom of $^{289}$Mc, from the 2n exit channel. This latter result was used to support the synthesis of tennessine. The 3n excitation function was completed with a maximum at ~8 pb. The data was consistent with that found in the first experiments in 2003.
This reaction was run again at five different energies in 2021 to test the new gas-filled separator at Dubna's SHE-factory. They detected 6 chains of $^{289}$Mc, 58 chains of $^{288}$Mc, and 2 chains of $^{287}$Mc. For the first time the 5n channel was observed with 2 atoms of $^{286}$Mc.

#### $^{242}$Pu($^{50}$Ti,pxn)$^{291−x}$Mc (x=2)

This reaction was studied by the team in Dubna in 2024. For the first time, a pxn reaction was successful with actinide targets and $^{48}$Ca/$^{50}$Ti/$^{54}$Cr projectiles, producing one atom of the known $^{289}$Mc in the p2n channel (evaporating one proton and two neutrons).

#### Reaction yields

The table below provides cross-sections and excitation energies for hot fusion reactions producing moscovium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.
| Projectile | Target | CN | 2n | 3n | 4n | 5n |
| $^{48}$Ca | $^{243}$Am | $^{291}$Mc | | 3.7 pb, 39.0 MeV | 0.9 pb, 44.4 MeV |

### Theoretical calculations
#### Decay characteristics

Theoretical calculations using a quantum-tunneling model support the experimental alpha-decay half-lives.

#### Evaporation residue cross sections

The table below contains various target-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.
MD = multi-dimensional; DNS = Di-nuclear system; σ = cross section
| Target | Projectile | CN | Channel (product) | σ$_{max}$ | Model |
| $^{243}$Am | $^{48}$Ca | $^{291}$Mc | 3n ($^{288}$Mc) | 3 pb | MD |
| $^{243}$Am | $^{48}$Ca | $^{291}$Mc | 4n ($^{287}$Mc) | 2 pb | MD |
| $^{243}$Am | $^{48}$Ca | $^{291}$Mc | 3n ($^{288}$Mc) | 1 pb | DNS |
| $^{242}$Am | $^{48}$Ca | $^{290}$Mc | 3n ($^{287}$Mc) | 2.5 pb | DNS |
| $^{241}$Am | $^{48}$Ca | $^{289}$Mc | 4n ($^{285}$Mc) | 1.04 pb | DNS |