Seaborgium (Sg)
transition-metalSolid
標準原子量
[271]電子配置
[Rn] 7s2 5f14 6d4融点
データなし沸点
データなし密度
3.5e+4 kg/m³酸化数
+3, +4, +5, +6電気陰性度（Pauling）
データなし第1イオン化エネルギー
7.8 eV発見年
1974原子半径
132 pm詳細
Seaborgium is a synthetic transactinide element in group 6, below tungsten. All confirmed isotopes are radioactive and short-lived, so its chemistry is studied atom by atom rather than in bulk. Experiments show that seaborgium behaves broadly as a heavier homolog of molybdenum and tungsten, with a stable +6 oxidation state in suitable compounds, while relativistic effects modify details of its volatility and complex formation.
Seaborgium does not occur naturally in the Earth’s crust. In 1974, seaborgium was first synthesized by Albert Ghiorso and his team at the University of California in Berkeley using the nuclear reaction 249Cf (18O, 4n) 263Sg. The element is named for Glenn T. Seaborg (Fig. IUPAC.106.1), who synthesized a number of trans-uranium elements [634], [648].
Seaborgium has no commercial applications. However, 265Sg was one of the decay products used to confirm the synthesis of copernicium in a particle accelerator experiment.
Seaborgium is named after Glenn Seaborg.
Seaborgium was first produced by a team of scientists led by Albert Ghiorso working at the Lawrence Berkeley Laboratory in Berkeley, California, in 1974. They created seaborgium by bombarding atoms of californium-249 with ions of oxygen-18 using a machine called the Super-Heavy Ion Linear Accelerator. The collision produced atoms of seaborgium-263 and four free neutrons. Seaborgium-263 is an isotope of seaborgium with a half-life of about 1 second. Three months before the Berkeley group announced their discovery, a team of scientists working at the Joint Institute for Nuclear Research in Dubna, Russia, claimed to have produced seaborgium. Their method involved bombarding atoms of lead-207 and lead-208 with ions of chromium-54 with a device called a cyclotron. They believed that they had produced atoms of seaborgium-259. The Berkeley group's work was confirmed in 1993 and they were credited with the discovery. Seaborgium's most stable isotope, seaborgium-271, has a half-life of about 2.4 minutes. It decays into rutherfordium-267 through alpha decay or decays through spontaneous fission..
IIn June 1974, members of the Joint Institute for Nuclear Research in Dubna, U.S.S.R., reported their discovery of Element 106, which they reported to have synthesized. Glenn Seaborg was part of this group, and the element was named in his honor.
In September 1974, workers of the Lawrence Berkeley and Livermore Laboratories also claimed creation Element 106 "without any scientific doubt." The LBL and LLL Group used the Super HILAC to accelerate 18O ions onto a 249Cf target.
Element 106 was created by the reaction 249Cf(18O, 4N)263X, which decayed by alpha emission to rutherfordium, and then by alpha emission to nobelium, which in turn further decayed by alpha between daughter and granddaughter. The element so identified had alpha energies of 9.06 and 9.25 MeV with a half-life of 0.9 +/- 0.2 s.
At Dubna, 280-MeV ions of 54Cr from the 310-cm cyclotron were used to strike targets of 206Pb, 207Pb, and 208Pb, in separate runs. Foils exposed to a rotating target disc were used to detect spontaneous fission activities. The foils were etched and examined microscopically to detect the number of fission tracks and the half-life of the fission activity. Other experiments were made to aid in confirmation of the discovery.
No macroscopic sample of seaborgium has been prepared, and its visible appearance is unknown. Calculations usually treat it as a very dense metallic solid under ordinary conditions, but this remains a prediction rather than an observed bulk property.
Seaborgium has no practical use outside scientific research. Its isotopes are produced in heavy-ion fusion experiments to study nuclear stability, decay chains, and the chemical behavior of the heaviest group 6 element. The element is valuable mainly because single atoms can test periodic trends and relativistic chemical models near the end of the actinide and transactinide region.
Since only a few atoms of seaborgium have ever been made, there are currently no uses for seaborgium outside of basic scientific research.
Seaborgium chemistry is known from rapid radiochemical experiments with individual atoms. The +6 oxidation state is the best established, consistent with group 6 chemistry. Volatile oxyhalides such as seaborgium oxychloride, SgO₂Cl₂, have been investigated by gas chromatography and compared with molybdenum oxychloride, MoO₂Cl₂, and tungsten oxychloride, WO₂Cl₂. Aqueous studies indicate formation of anionic oxo and oxofluoride complexes, but only fleeting trace quantities have been observed.
See more information at the Seaborgium compound page.
The safety properties of seaborgium are dominated by radioactivity, not chemical toxicity. The few atoms made in laboratories decay by alpha emission or spontaneous fission, depending on the isotope. External exposure from produced quantities is negligible, but accelerator targets, recoil products, and contaminated equipment are handled with radiological controls appropriate for heavy-ion nuclear research.
Seaborgium has no confirmed natural occurrence and no environmental cycle. Any atoms produced in a laboratory decay rapidly to other nuclides and are confined to experimental apparatus. Its environmental chemistry has not been observed directly, and ordinary ecological behavior cannot be assigned to an element produced only atom by atom.
Seaborgium has no commodity market, industrial supply chain, or recoverable inventory. It is made only in specialized accelerator facilities by bombarding heavy actinide targets with lighter ions, producing at most a few atoms at a time. The cost is therefore tied to nuclear research infrastructure, target preparation, beam time, and detection systems rather than to mining, refining, or commercial demand. Recycling in the usual materials sense is not applicable.
Made by bombarding californium-249 with oxygen-18.
Seaborgium is not expected to persist naturally in the universe because its known isotopes have very short half-lives. It may be formed transiently in extreme nuclear reactions, but any such atoms would decay quickly. It is not a significant constituent of stars, planets, meteorites, or interstellar material.
- Seaborgium was the first element named after a living person at the time the name was approved.
- Its chemistry must be measured before the atom decays, often within seconds.
- Gas-phase experiments compare seaborgium directly with molybdenum and tungsten compounds.
- Several seaborgium isotopes are identified through decay chains ending in better-known nuclei.
- Only atom-at-a-time chemistry is possible with present production methods.
画像
性質
物理的性質
- 原子半径（経験値）
- 132 pm 全元素の原子半径（経験値）を比較 →
- 密度
- 3.5 × 104 kg/m³ 全元素の密度を比較 →
化学的性質
- 電子親和力
- 0.85 eV
- 第1イオン化エネルギー
- 7.8 eV 全元素の第1イオン化エネルギーを比較 →
- 第2イオン化エネルギー
- 17.100059 eV 全元素の第2イオン化エネルギーを比較 →
- 第3イオン化エネルギー
- 25.800089 eV 全元素の第3イオン化エネルギーを比較 →
- 第4イオン化エネルギー
- 35.500122 eV 全元素の第4イオン化エネルギーを比較 →
- 第5イオン化エネルギー
- 47.200162 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- +3, +4, +5, +6 全元素の酸化数を比較 →
- 価電子
- 6 全元素の価電子を比較 →
- 電子配置
- [Rn] 7s2 5f14 6d4
熱力学的性質
データなし
原子核
- 陽子数
- 106 全元素の陽子数を比較 →
- 中性子数
- 163 全元素の中性子数を比較 →
- 既知の同位体
- 16 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）
- 271
- 最も安定な同位体
- Sg-269
- 発見年
- 1974
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
- 2, 8, 18, 32, 32, 12, 2 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 54038-81-2 全元素のCAS登録番号を比較 →
- 項記号
- 0
- InChI
- InChI=1S/Sg
- InChI Key
- VAOUCABZIBBBJH-UHFFFAOYSA-N
電子配置 予測値
Sg: 5f¹⁴ 6d⁴ 7s²[Rn] 5f¹⁴ 6d⁴ 7s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 5f¹⁴ 6d⁴ 7s²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。
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 |
|---|---|---|---|
| 263 放射性 | 263.11829 ± 0.0001 | データなし | 940 ms |
| 259 放射性 | 259.1144 ± 0.00013 | データなし | 402 ms |
| 266 放射性 | 266.12198 ± 0.00026 | データなし | 390 ms |
| 261 放射性 | 261.115949 ± 0.00002 | データなし | 183 ms |
| 264 放射性 | 264.11893 ± 0.0003 | データなし | 78 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95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 |
|---|---|---|
| Sg I | 0 | 2 |
| Sg II | +1 | 2 |
| Sg III | +2 | 2 |
| Sg IV | +3 | 2 |
| Sg V | +4 | 2 |
| Sg VI | +5 | 2 |
| Sg VII | +6 | 2 |
| Sg VIII | +7 | 2 |
| Sg IX | +8 | 2 |
| Sg X | +9 | 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 | |
|---|---|---|---|---|---|
| 263 放射性 | 263.11829 ± 0.0001 | データなし | 940 ms | α =87±0.8%SF =13±0.8% | |
| 259 放射性 | 259.1144 ± 0.00013 | データなし | 402 ms | α ≈100%SF ?β+ ? | |
| 266 放射性 | 266.12198 ± 0.00026 | データなし | 390 ms | SF>90% | |
| 261 放射性 | 261.115949 ± 0.00002 | データなし | 183 ms | α =98.1±0.4%β+ =1.3±0.3%SF =0.6±0.2% | |
| 264 放射性 | 264.11893 ± 0.0003 | データなし | 78 ms | SF>80% α ? |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 143 pm
- 共有結合半径（Pyykkö、二重結合）
- 128 pm
- 共有結合半径（Pyykkö、三重結合）
- 121 pm
番号付けの尺度
- Mendeleev
- 54
分極率と分散
- 双極子分極率
- 40 a.u.
- 双極子分極率（不確かさ）
- 4 a.u.
酸化数の分類
専門参考データ
同位体の崩壊形式 (32)
| 同位体 | モード | 強度 |
|---|---|---|
| 258 | SF | 100% |
| 258 | A | — |
| 259 | A | 100% |
| 259 | SF | — |
| 259 | B+ | — |
| 260 | SF | 71% |
| 260 | A | 29% |
| 261 | A | 98.1% |
| 261 | B+ | 1.3% |
| 261 | SF | 0.6% |
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] Seaborgium https://education.jlab.org/itselemental/ele106.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
Not Applicable
参考文献 (1)
- [5] Seaborgium https://education.jlab.org/itselemental/ele106.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. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Seaborgium.