Roentgenium (Rg)
transition-metalExpected to be a Solid
標準原子量
281 u電子配置
[Rn] 7s2 5f14 6d9 (予測値)融点
データなし沸点
データなし密度
2.87e+4 kg/m³酸化数
−1, +1, +3, +5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
1994原子半径
138 pm詳細
Roentgenium is a synthetic transactinide element in group 11, below gold. It has been made only one atom at a time in heavy-ion fusion experiments, and all confirmed isotopes are highly radioactive and short-lived. Its chemistry has not been established experimentally in bulk or solution. Relativistic calculations generally place it among the coinage metals, but with properties that may differ appreciably from lighter homologues.
Roentgenium does not occur naturally in the Earth’s crust. Roentgenium was first synthesized by an international team of scientists from the GSI in Darmstadt, Germany, the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, the Comenius University in Bratislava, Slovakia, and the University of Jyväskylä, Finland at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany in 1994, using the nuclear reaction 209Bi (64Ni, n) 272Rg. The credit for the first synthesis was confirmed in 2003. The element was named after Wilhelm Conrad Roentgen (Fig. IUPAC.111.1), who discovered X-rays in 1895 [660], [661], [662]. Roentgenium has no known isotopic applications aside from scientific research.
Roentgenium is named after Wilhelm Conrad Röntgen.
Roentgenium was first produced by Peter Armbruster, Gottfried Münzenber and their team working at the Gesellschaft für Schwerionenforschung in Darmstadt, Germany in late 1994. They bombarded atoms of bismuth-209 with ions of nickel-64 with a device known as a linear accelerator. This produced three atoms of roentgenium-272, an isotope with a half-life of about 1.5 milliseconds (0.0015 seconds), and a free neutron. Roentgenium's most stable isotope, roentgenium-281, has a half-life of about 26 seconds and decays through spontaneous fission.
Discovered by Gesellschaft Schwerionenforschung (GSI) in Darmstadt, in 1994. Reasearch group of S. Hofmann, V. Ninov, F.P. Hessberger, P. Armbruster, H. Folger, G. Munzenberg, H.J. Schott, and others.
No macroscopic sample of roentgenium has ever been prepared, so its appearance is unknown. A bulk metal, if it could exist long enough, is expected from theory to be dense and metallic, but color, surface behavior, and ordinary physical constants have not been measured.
Roentgenium has no practical, commercial, medical, or industrial use. Its only use is in nuclear research, where individual atoms and their decay chains help test models of heavy-element formation, nuclear stability, and alpha decay. Experiments involving roentgenium also support the identification of neighboring superheavy nuclei, but the element is not available as a material for devices, tracers, or chemical applications.
Since only a few atoms of roentgenium have ever been produced, it currently has no uses outside of basic scientific research.
No confirmed roentgenium compound has been isolated or characterized. The element is expected to show group 11 chemistry in some respects, but strong relativistic effects make detailed predictions uncertain. The +1 and +3 oxidation states are commonly discussed in theoretical work, with possible analogies to gold compounds such as gold(III) chloride, AuCl₃, rather than to the more stable simple chemistry of copper or silver. Proposed species such as roentgenium fluorides or chlorides remain predictions, not observed substances.
See more information at the Roentgenium compound page.
The safety properties of roentgenium are governed by radioactivity rather than ordinary chemical toxicity. Known isotopes decay rapidly, mainly through alpha decay and spontaneous fission pathways within decay chains. The quantities produced are far below a macroscopic hazard under normal laboratory containment, but any experiment requires specialized radiological controls for heavy-ion target materials, recoil products, and short-lived radioactive daughters.
Roentgenium has no confirmed natural occurrence and no environmental cycle. Any atoms produced in a laboratory decay before they could disperse or participate in ordinary geochemical processes. Environmental relevance is therefore limited to controlled accelerator facilities and to the management of irradiated targets, catcher foils, and associated radioactive residues from superheavy-element experiments.
Roentgenium is not a commodity and has no market price, supply chain, or recycling practice. Production requires a heavy-ion accelerator, rare target materials, and long experiments with extremely low atom yields. The element is identified through decay correlations rather than collected as a product. Economic considerations are those of publicly or institutionally funded nuclear-physics research, including accelerator time, target preparation, detector systems, and radiological handling.
Made by bombarding bismuth-209 with nickel-60.
Roentgenium is not expected to be a persistent cosmic element because its known isotopes are too unstable. If nuclei with 111 protons are formed transiently in extreme nucleosynthetic environments, they would decay quickly unless an unknown much longer-lived isotope exists. No roentgenium has been detected in stars, meteorites, planets, or terrestrial minerals.
- Roentgenium was named in honor of Wilhelm Conrad Röntgen, discoverer of X-rays.
- Its identification relies on linking a few decay events to known daughter nuclei.
- The longest-lived confirmed isotopes still have half-lives far too short for chemical stockpiles.
- Roentgenium lies in the same periodic-table group as copper, silver, and gold.
- Chemical experiments have not yet established a measured oxidation state for roentgenium.
画像
性質
物理的性質
- 原子半径（経験値）
- 138 pm 全元素の原子半径（経験値）を比較 →
- 密度
- 2.87 × 104 kg/m³ 全元素の密度を比較 →
化学的性質
- 電子親和力
- 1.6 eV
- 酸化数
- −1, +1, +3, +5 全元素の酸化数を比較 →
- 価電子
- 2 全元素の価電子を比較 →
- 電子配置
- [Rn] 7s2 5f14 6d9 (予測値)
熱力学的性質
データなし
原子核
- 陽子数
- 111 全元素の陽子数を比較 →
- 中性子数
- 171 全元素の中性子数を比較 →
- 既知の同位体
- 15 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）
- 282
- 最も安定な同位体
- Rg-282
- 発見年
- 1994
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, 9, 2 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 54386-24-2 全元素のCAS登録番号を比較 →
- InChI
- InChI=1S/Rg
- InChI Key
- LJROPTGWFUZRDB-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 |
|---|---|---|---|
| 279 放射性 | 279.16272 ± 0.00051 | データなし | 170 ms |
| 282 放射性 | 282.16912 ± 0.00072 | データなし | 130 秒 |
| 285 放射性 | 285.175771 ± 0.000644 | データなし | 30 秒 |
| 274 放射性 | 274.15525 ± 0.00019 | データなし | 20 ms |
| 281 放射性 | 281.16636 ± 0.00089 | データなし | 19 秒 |
相／状態
相・状態のデータはありません
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 | |
|---|---|---|---|---|---|
| 279 放射性 | 279.16272 ± 0.00051 | データなし | 170 ms | α =100% | |
| 282 放射性 | 282.16912 ± 0.00072 | データなし | 130 秒 | α =100% | |
| 285 放射性 | 285.175771 ± 0.000644 | データなし | 30 秒 | α ?SF ? | |
| 274 放射性 | 274.15525 ± 0.00019 | データなし | 20 ms | α ≈100% | |
| 281 放射性 | 281.16636 ± 0.00089 | データなし | 19 秒 | SF =87±0.8%α =13±0.8% |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 121 pm
- 共有結合半径（Pyykkö、二重結合）
- 116 pm
- 共有結合半径（Pyykkö、三重結合）
- 118 pm
番号付けの尺度
- Mendeleev
- 74
分極率と分散
- 双極子分極率
- 32 a.u.
- 双極子分極率（不確かさ）
- 6 a.u.
酸化数の分類
専門参考データ
同位体の崩壊形式 (22)
| 同位体 | モード | 強度 |
|---|---|---|
| 272 | A | 100% |
| 273 | A | — |
| 274 | A | 100% |
| 275 | A | — |
| 276 | A | — |
| 276 | SF | — |
| 277 | A | — |
| 277 | SF | — |
| 278 | A | 100% |
| 279 | 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] Roentgenium https://education.jlab.org/itselemental/ele111.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
参考文献 (1)
- [5] Roentgenium https://education.jlab.org/itselemental/ele111.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 Roentgenium.