Meitnerium (Mt)
transition-metalSolid
標準原子量
[278]電子配置
[Rn] 7s2 5f14 6d7 (計算値)融点
データなし沸点
データなし密度
3.74e+4 kg/m³酸化数
+1, +3, +4, +6, +8, +9電気陰性度（Pauling）
データなし第1イオン化エネルギー
データなし発見年
1982原子半径
128 pm詳細
Meitnerium is a synthetic transactinide element in group 9, below cobalt, rhodium, and iridium. It has been made only atom by atom in heavy-ion accelerator experiments, and all known isotopes are radioactive with very short half-lives. Its chemistry is expected to be influenced strongly by relativistic effects, but direct chemical data are extremely limited or absent. The element is chiefly significant for nuclear-structure studies of the heaviest nuclei.
Meitnerium does not occur naturally in the Earth’s crust. Meitnerium was first synthesized by German scientists at the GSI Center for Heavy Ion Research in Darmstadt, Germany in 1984 using the nuclear reaction 209Bi (58Fe, n) 266MtHs. The element is named for the physicist, Lise Meitner (Fig. IUPAC.109.1), who discovered the element protactinium [653], [655]. Meitnerium is used only for scientific research.
Meitnerium is named after Lise Meitner.
Meitnerium was first produced by Peter Armbruster, Gottfried Münzenber and their team working at the Gesellschaft für Schwerionenforschung in Darmstadt, Germany in 1982. They bombarded atoms of bismuth-209 with ions of iron-58 with a device known as a linear accelerator. This produced atoms of meitnerium-266, an isotope with a half-life of about 3.8 milliseconds (0.0038 seconds), and a free neutron. Meitnerium's most stable isotope, meitnerium-278, has a half-life of about 8 seconds. It decays into bohrium-274 through alpha decay.
On August 29, 1982, physicists at the Heavy Ion Research Laboratory, Darmstadt, West Germany made and identified element 109 by bombing a target of 209Bi with accelerated nuclei of 58Fe. If the combined energy of two nuclei is sufficiently high, the repulsive forces between the nuclei can be overcome.
In this experiment, a week of target bombardment was required to produce a single fused nucleus. The team confirmed the existence of element 109 by four independent measurements. The newly formed atom recoiled from the target at predicted velocity and was separated from smaller, faster nuclei by a newly developed velocity filter. The time of flight to the detector and the striking energy were measured and found to match predicted values.
The nucleus of 266X started to decay 5 ms after striking the detector. A high-energy alpha particle was emitted, producing 262/107X. This in turn emitted an alpha particle, becoming 258/105Db, which in turn captured an electron and became 258/104Rf. This in turn decayed into other nuclides. This experiment demonstrated the feasibility of using fusion techniques as a method of making new, heavy nuclei.
No macroscopic sample of meitnerium has been prepared, so its visible appearance and bulk physical properties are unknown. Calculations usually treat it as a dense metallic solid under ordinary conditions, broadly analogous to the heavier platinum-group metals, but this remains unobserved.
Meitnerium has no practical commercial, medical, or industrial use. Its use is confined to basic research, where individual atoms are produced and identified through their decay chains. These experiments test models of nuclear stability, fusion-evaporation reactions, and detector methods for superheavy elements. Some meitnerium isotopes also appear as daughters in decay chains from still heavier synthetic elements, providing evidence used to link and verify those chains.
Since only small amounts of meitnerium have ever been produced, it currently has no uses outside of basic scientific research.
No bulk compound of meitnerium has been isolated, and its chemical behavior has not been characterized in ordinary laboratory quantities. As a group 9 element it is expected to show some resemblance to iridium, with metallic bonding and possible positive oxidation states, especially +3, in suitable compounds. Theoretical work has considered species such as meitnerium hexafluoride, MtF₆, and oxo or halide complexes, but these predictions have not been confirmed by direct compound isolation. Relativistic effects may alter ligand bonding compared with lighter homologues.
See more information at the Meitnerium compound page.
The safety concerns for meitnerium are radiological rather than chemical, because only individual atoms are produced. Known isotopes decay mainly by alpha emission and sometimes through decay modes that lead quickly to other radioactive nuclides. Chemical toxicity has not been measured and is not practically separable from the radiation hazard. Experiments require accelerator shielding, contamination control for radioactive targets and recoils, and remote handling appropriate to the associated nuclear materials.
Meitnerium has no confirmed natural occurrence and no known environmental cycle. Atoms made in accelerators are formed in targets, recoil separators, or detector systems and decay rapidly. The quantities are far too small and short-lived for observed transport, bioaccumulation, or ecological effects. Any environmental concern from its production would instead come from activated equipment, target materials, and daughter radionuclides handled in the laboratory.
Meitnerium has no commodity market, no industrial supply chain, and no recoverable stock. It is produced only in specialized nuclear physics facilities by bombarding heavy target nuclei with accelerated ions, commonly in fusion-evaporation reactions designed to make a few atoms. The limiting factors are accelerator time, target preparation, detection efficiency, and the very low reaction probability, not raw material demand. Recycling is not meaningful for the element itself because the atoms decay before collection as material.
Obtained by bombarding bismuth-209 with iron-58.
Meitnerium is not expected to be a primordial element, because its known isotopes are far too short-lived to survive since the formation of the Solar System. It may be formed fleetingly in extreme nucleosynthetic environments, if at all, but no extraterrestrial occurrence has been observed. Its relevance to cosmic chemistry is mainly theoretical, in discussions of the limits of nuclear stability.
- Meitnerium was first identified in experiments at GSI Darmstadt in 1982.
- It is named for the physicist Lise Meitner.
- The first reported isotope was ²⁶⁶Mt, made from bismuth and iron nuclei.
- Only atom-at-a-time nuclear decay data are available for most meitnerium isotopes.
- Meitnerium sits in the same periodic group as iridium, but its chemistry remains essentially untested.
画像
性質
物理的性質
- 原子半径（経験値）
- 128 pm 全元素の原子半径（経験値）を比較 →
- 密度
- 3.74 × 104 kg/m³ 全元素の密度を比較 →
化学的性質
- 電子親和力
- 1.7 eV
- 第5イオン化エネルギー
- 50.000172 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- +1, +3, +4, +6, +8, +9 全元素の酸化数を比較 →
- 価電子
- 25 全元素の価電子を比較 →
- 電子配置
- [Rn] 7s2 5f14 6d7 (計算値)
熱力学的性質
データなし
原子核
- 陽子数
- 109 全元素の陽子数を比較 →
- 中性子数
- 170 全元素の中性子数を比較 →
- 既知の同位体
- 18 全元素の既知の同位体を比較 →
- 安定同位体
- 0 全元素の安定同位体を比較 →
- 質量数（最も安定な同位体）
- 278
- 最も安定な同位体
- Mt-279
- 発見年
- 1982
存在度
データなし
結晶構造
データなし
電子構造
- 各電子殻の電子数
- 7, 25 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 54038-01-6 全元素のCAS登録番号を比較 →
- InChI
- InChI=1S/Mt
- InChI Key
- VAJSJTKWMRUWBF-UHFFFAOYSA-N
電子配置 予測値
——このイオンの電子配置データはありません。
原子モデル
同位体によって中性子数、質量、安定性は変わりますが、中性原子の電子配置は変わりません。
データなし
模式的な原子モデルです。実際の縮尺とは異なります。
原子の指紋
発光／吸収スペクトル
同位体分布
安定同位体はありません。
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 |
|---|---|---|---|
| 274 放射性 | 274.14724 ± 0.00038 | データなし | 850 ms |
| 270 放射性 | 270.14033 ± 0.00018 | データなし | 800 ms |
| 273 放射性 | 273.1444 ± 0.00052 | データなし | 800 ms |
| 276 放射性 | 276.15159 ± 0.00059 | データなし | 700 ms |
| 271 放射性 | 271.14074 ± 0.00035 | データなし | 400 ms |
相／状態
相・状態のデータはありません
原子スペクトル
全94件中10件を表示しています。 イオンの電荷の昇順で並べています。
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Mt V | +4 | 2 |
| Mt VI | +5 | 1 |
| Mt VII | +6 | 1 |
| Mt VIII | +7 | 2 |
| Mt IX | +8 | 2 |
| Mt X | +9 | 2 |
| Mt XI | +10 | 2 |
| Mt XII | +11 | 2 |
| Mt XIII | +12 | 2 |
| Mt XIV | +13 | 2 |
相・状態のデータはありません
化合物
同位体 (5)
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 274 放射性 | 274.14724 ± 0.00038 | データなし | 850 ms | α =100% | |
| 270 放射性 | 270.14033 ± 0.00018 | データなし | 800 ms | α ≈100% | |
| 273 放射性 | 273.1444 ± 0.00052 | データなし | 800 ms | α ?SF ? | |
| 276 放射性 | 276.15159 ± 0.00059 | データなし | 700 ms | α =100% | |
| 271 放射性 | 271.14074 ± 0.00035 | データなし | 400 ms | α ? |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 129 pm
- 共有結合半径（Pyykkö、二重結合）
- 125 pm
- 共有結合半径（Pyykkö、三重結合）
- 113 pm
番号付けの尺度
- Mendeleev
- 66
分極率と分散
- 双極子分極率
- 34 a.u.
- 双極子分極率（不確かさ）
- 3 a.u.
酸化数の分類
専門参考データ
同位体の崩壊形式 (26)
| 同位体 | モード | 強度 |
|---|---|---|
| 265 | A | — |
| 266 | A | 100% |
| 266 | SF | — |
| 267 | A | — |
| 268 | A | 100% |
| 269 | A | — |
| 270 | A | 100% |
| 271 | A | — |
| 272 | A | — |
| 272 | SF | — |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
Not Applicable
参考文献 (1)
- [5] Meitnerium https://education.jlab.org/itselemental/ele109.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
参考文献 (1)
- [5] Meitnerium https://education.jlab.org/itselemental/ele109.html
参考文献
(8)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements.
This section provides all form of data related to element Meitnerium.