Nihonium (Nh)
post-transition-metalExpected to be a Solid
標準原子量
[286]電子配置
[Rn] 5f14 6d10 7s2 7p1 (予測値)融点
426.85 °C沸点
1156.85 °C密度
1.6e+4 kg/m³酸化数
データなし電気陰性度（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
2004原子半径
170 pm詳細
Nihonium is a synthetic transactinide element in group 13, below thallium. It has been identified only as individual atoms produced in heavy-ion nuclear reactions, chiefly through decay chains from heavier nuclei and by direct fusion experiments. Its chemistry has not been characterized experimentally in bulk. Relativistic calculations predict that nihonium may differ markedly from lighter group 13 elements, with a particularly stable +1 oxidation state and a less accessible +3 state.
Nihonium does not occur naturally in the Earth’s crust. The name nihonium and the symbol Nh are the accepted ones for element 113. Nihon is one of the two ways to say “Japan” in Japanese and means “the land of the Rising Sun.” It is the first element to have been discovered in an Asian country [665], [666], [667].
The synthesis of nihonium was first announced in 2004. The Joint Institute for Nuclear Research (JINR) and the Lawrence Livermore National Laboratory were able to produce two super-heavy elements by bombarding a rotating 243Am disc with an ion beam of 48Ca in a U-400 cyclotron. During the reaction, isotopes of moscovium, previously known as ununpentium, were synthesized and decayed in a tenth of a second to nihonium, which then decayed to roentgenium. Because the atoms of moscovium only existed for a tenth of a second, radiochemical proof was needed to support its syntheses. A Swiss scientist at the Paul Scherrer Institute (PSI) performed the radiochemical experiment by analyzing a copper plate that had been placed behind the 243Am disc in the cyclotron. This copper plate collected all moscovium atoms that were synthesized and was processed through liquid chromatography techniques that yielded five times more moscovium atoms than produced by fusion alone. The direct synthesis of nihonium was announced later that year by a team of Japanese scientists from the Cyclotron Center of the RIKEN Research Institute. These scientists bombarded atoms of 209Bi with a beam of 70Zn in a RIKEN heavy-ion linear accelerator (RILAC), shown in Fig. IUPAC.113.1, and gas-filled recoil ion separator (GARIS), shown in Fig. IUPAC.113.2. Nihonium has no known isotopic applications aside from scientific research.
On July 23, 2004, scientists working at the RIKEN Nishina Center for Accelerator-based Science in Wako, Japan, created the first two atoms of the element nihonium by accelerating zinc ions to 10 percent the speed of light and then impacting them onto a thin bismuth target. Both atoms quickly underwent a series of four alpha decays, forming dubnium-262, which then decayed by spontaneous fission. Nihonium's most stable isotope, nihonium-286, has a half-life of about 20 seconds. It decays into roentgenium-282 through alpha decay.
On November 28th, 2016 element 113 was named “nihonium” with the symbol Nh. The name was proposed by the discoverers at RIKEN Nishina Center for Accelerator-Based Science in Japan. The name means mean “the Land of Rising Sun” and comes from the word “Nihon,” which means “Japan” in Japanese.
No macroscopic sample of nihonium has ever been made, so its color, texture, density, melting point, and other ordinary bulk properties are unknown. Any description of a metallic appearance is a theoretical expectation rather than an observation.
Nihonium has no practical use outside nuclear research. Its known isotopes are produced atom by atom and decay too quickly for materials applications, commercial chemistry, or radiological sources. Its value is scientific: production and decay measurements test models of superheavy nuclei, help map decay chains near the predicted island of stability, and provide benchmarks for relativistic calculations of very heavy elements.
Since only a few atoms of nihonium have ever been produced, it currently has no uses outside of basic scientific research.
No confirmed nihonium compound has been isolated or chemically characterized. By periodic position it belongs to group 13, but relativistic effects are expected to strongly affect its valence electrons. Calculations commonly predict Nh⁺ chemistry to be important, with Nh³⁺ less stable than the +3 states of aluminum, gallium, and indium. Possible halides such as nihonium(I) chloride, NhCl, or nihonium(III) chloride, NhCl₃, are theoretical species, not known preparations.
See more information at the Nihonium compound page.
The safety properties of nihonium are governed by radioactivity and the impracticality of producing more than a few atoms. Known isotopes are short-lived alpha-emitting nuclei or decay through related radioactive chains, with half-lives that are isotope-specific. There is no ordinary chemical exposure scenario, but any experiment requires containment and radiological controls appropriate for heavy-ion target work and decay detection.
Nihonium has no confirmed natural occurrence and no environmental cycle. Atoms made in laboratories decay before they could disperse or participate in environmental chemistry. Any environmental concern is therefore associated with accelerator targets, beamline materials, and radioactive daughter products used or produced in the experiment, not with persistent nihonium contamination.
Nihonium has no commodity market, industrial supply, or recycling stream. It is made only in specialized accelerator experiments by bombarding heavy actinide targets with ion beams, followed by detection of a few decay events. The limiting factors are access to high-intensity accelerators, rare target isotopes, long irradiation times, and highly sensitive detectors, rather than separable product yield. Substitution is irrelevant because there is no practical application to supply.
Made by bombardng bismuth-209 with zinc-70.
Nihonium is not expected to occur naturally in the universe in persistent amounts. Superheavy nuclei may be formed transiently in extreme nucleosynthetic environments, but isotopes of element 113 known or expected near present experiments decay rapidly. No extraterrestrial reservoir or spectroscopic detection is known.
- Nihonium was the first element named after Japan, from Nihon, a Japanese name for Japan.
- Its accepted discovery involved decay chains assigned to atoms made one at a time.
- The longest-lived confirmed nihonium isotopes still have half-lives far too short for ordinary chemical handling.
- For nihonium, periodic-table position is a weaker guide than usual because relativistic effects are large.
画像
性質
物理的性質
- 原子半径（経験値）
- 170 pm 全元素の原子半径（経験値）を比較 →
- 密度
- 1.6 × 104 kg/m³ 全元素の密度を比較 →
- 標準温度・圧力（STP）での相
- 固体 全元素の標準温度・圧力（STP）での相を比較 →
- 融点
- 426.85 °C 全元素の融点を比較 →
- 沸点
- 1156.85 °C 全元素の沸点を比較 →
化学的性質
- 電子親和力
- 0.6 eV
- 価電子
- 3 全元素の価電子を比較 →
- 電子配置
- [Rn] 5f14 6d10 7s2 7p1 (予測値)
熱力学的性質
データなし
原子核
- 陽子数
- 113 全元素の陽子数を比較 →
- 中性子数
- 176 全元素の中性子数を比較 →
- 既知の同位体
- 13 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）
- 286
- 最も安定な同位体
- Nh-289
- 発見年
- 2004
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
- 14, 10, 3 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 54084-70-7 全元素のCAS登録番号を比較 →
- InChI
- InChI=1S/Nh
- InChI Key
- KUGNSLWRKGRKGS-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 |
|---|---|---|---|
| 282 放射性 | 282.17567 ± 0.00039 | データなし | 140 ms |
| 283 放射性 | 283.17657 ± 0.00052 | データなし | 140 ms |
| 281 放射性 | 281.17348 ± 0.00075 | データなし | 100 ms |
| 289 放射性 | 289.188461 ± 0.000537 | データなし | 30 秒 |
| 287 放射性 | 287.18339 ± 0.00081 | データなし | 20 秒 |
相／状態
理由: 融点（426.85 °C）より401.9 °C低い
模式図、実際の縮尺とは異なります
相転移点
密度
標準条件下
標準条件下
結晶構造のデータはありません
同位体 (5)
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 282 放射性 | 282.17567 ± 0.00039 | データなし | 140 ms | α =100% | |
| 283 放射性 | 283.17657 ± 0.00052 | データなし | 140 ms | α =100% | |
| 281 放射性 | 281.17348 ± 0.00075 | データなし | 100 ms | α ?SF ? | |
| 289 放射性 | 289.188461 ± 0.000537 | データなし | 30 秒 | α ?SF ? | |
| 287 放射性 | 287.18339 ± 0.00081 | データなし | 20 秒 | α ?SF ? |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 136 pm
番号付けの尺度
- Mendeleev
- 86
分極率と分散
- 双極子分極率
- 29 a.u.
- 双極子分極率（不確かさ）
- 2 a.u.
専門参考データ
同位体の崩壊形式 (20)
| 同位体 | モード | 強度 |
|---|---|---|
| 278 | A | 100% |
| 279 | A | — |
| 279 | SF | — |
| 280 | A | — |
| 280 | SF | — |
| 281 | A | — |
| 281 | SF | — |
| 282 | A | 100% |
| 283 | A | 100% |
| 284 | A | 100% |
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] Nihonium https://education.jlab.org/itselemental/ele113.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
参考文献 (1)
- [5] Nihonium https://education.jlab.org/itselemental/ele113.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 Nihonium.