Meitnerium
Atomic Data
| Atomic Number | 109 |
| Symbol | Mt |
| Atomic Weight | 278 u |
| Density (STP) | N/A |
| Melting Point | N/A °C (None K) |
| Boiling Point | N/A °C (None K) |
| Electronegativity | : |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d7 7s2 |
| Oxidation States | +3, +6 |
| Phase at STP | Solid |
| Category | Transition Metal |
| Period / Group | 7 / 9 |
| CAS Number | 54038-01-6 |
Electron Configuration
[Rn] 5f14 6d7 7s2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| N | 4 | 4f | 14 | 60 |
| O | 5 | 5s | 2 | 62 |
| O | 5 | 5p | 6 | 68 |
| O | 5 | 5d | 10 | 78 |
| O | 5 | 5f | 14 | 92 |
| P | 6 | 6s | 2 | 94 |
| P | 6 | 6p | 6 | 100 |
| P | 6 | 6d | 7 | 107 |
| Q | 7 | 7s | 2 | 109 |
| Total | 109 | 109 | ||
Isotopes of Meitnerium
Meitnerium is monoisotopic: ²⁷⁸Mt is its only naturally occurring stable isotope, accounting for 100% of all natural Meitnerium.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Meitnerium-278 | ²⁷⁸Mt | 109 | 169 | trace | Stable |
Abundance & Occurrence
Meitnerium is present in Earth's crust at approximately trace amounts by mass and at approximately trace amounts by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Alpha radiation and very short half-life: Meitnerium isotopes are alpha emitters with half-lives of seconds to milliseconds; Mt-278 (t½ = 4.5 s) is among the longer-lived, permitting only the most rapid automated chemical experiments.
- Atom-at-a-time scale: Only a few dozen atoms of meitnerium have ever been produced; there is no practical bulk hazard from the element itself.
- Accelerator environment: The primary safety concern at meitnerium experiments is the radiation environment of the GSI or RIKEN heavy ion accelerator, not the element.
- Regulatory controls: All transactinide experiments take place at licensed nuclear facilities under comprehensive radiation protection and material accountancy programmes.
Meitnerium in the Real World
Real-World Uses
- Superheavy element nuclear research: Meitnerium (Mt-276, Mt-278) is produced in cold and hot fusion reactions at accelerators to study its nuclear decay properties; it lies along the decay chains of elements 113, 115, and 117, providing identification links for these heavier species.
- Testing limits of the periodic table: Meitnerium is predicted to be in Group 9 (homologue of cobalt, rhodium, and iridium); relativistic calculations predict significant deviations in its chemistry, but experimental confirmation awaits production of sufficient quantities for chemical study.
- No commercial applications: Meitnerium is produced a few atoms at a time with half-lives of seconds to tenths of seconds; no practical application is conceivable.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
Has meitnerium ever been used for anything?
No. Meitnerium has no known practical uses. Its most stable isotope (Mt-278) has a half-life of about 4 seconds. It is produced only a few atoms at a time in particle accelerators and used solely for fundamental nuclear physics research. No chemical experiments have been successfully performed on meitnerium due to its extremely short half-life.
How many atoms of meitnerium have been made?
Meitnerium has been produced in very small quantities: typically a few atoms per experiment: at particle accelerator facilities. It was first synthesised in 1982 at GSI in Darmstadt by bombarding bismuth-209 with iron-58 ions. Only a few dozen atoms total have been produced across all experiments since its discovery.
Is meitnerium radioactive?
Yes, all isotopes of meitnerium are radioactive. The most stable, Mt-278, has a half-life of about 4 seconds. It decays by alpha emission. All meitnerium atoms are produced and decay almost immediately in particle accelerator experiments.
How did meitnerium get its name?
Meitnerium was named after Lise Meitner, the Austrian-Swedish physicist who co-discovered nuclear fission and made fundamental contributions to nuclear physics. Despite her crucial role in the discovery of fission, Meitner was controversially excluded from the 1944 Nobel Prize awarded to Otto Hahn for the discovery. Naming element 109 after her was widely considered a posthumous recognition of her overlooked contributions to science.