Selenium (Se)
nonmetalSolid
標準原子量
78.971 u電子配置
[Ar] 4s2 3d10 4p4融点
220.5 °C沸点
684.85 °C密度
4809 kg/m³酸化数
−2, −1, 0, +1, +2, +3, +4, +5, +6電気陰性度（Pauling）
2.55第1イオン化エネルギー
9.752368 eV発見年
1817原子半径
115 pm詳細
Selenium is a chalcogen between sulfur and tellurium, with chemistry that commonly parallels both. It is a trace element required by many organisms because it is incorporated into selenoproteins, yet the margin between nutritional requirement and toxicity is narrow. Industrially, selenium is valued for its semiconductor and photoconductive behavior, its red color in glass, and its role in metallurgy and specialty chemicals.
Selenium exists in several allotropic forms, although three are generally recognized. Selenium can be prepared with either an amorphous or a crystalline structure. The color of amorphous selenium is either red (in powder form) or black (in vitreous form). Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a metallic gray.
Selenium exhibits both photovoltaic action, where light is converted directly into electricity, and photoconductive action, where the electrical resistance decreases with increased illumination. These properties make selenium useful in the production of photocells and exposure meters for photographic use, as well as solar cells. Selenium is also able to convert a.c. electricity to d.c., and is extensively used in rectifiers. Below its melting point, selenium is a p-type semiconductor and has many uses in electronic and solid-state applications.
Elemental selenium has been said to be practically nontoxic and is considered to be an essential trace element; however, hydrogen selenide and other selenium compounds are extremely toxic, and resemble arsenic in their physiological reactions.
The name derives from the Greek Selene, who was the Greek goddess of the Moon because the element is chemically found with tellurium (Tellus was the Roman goddess of the Earth). Selenium was discovered by the Swedish chemist Jöns Jacob Berzelius in 1817, while trying to isolate tellurium in an impure sample.
Selenium was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1817 after analyzing an impurity that was contaminating the sulfuric acid (H2SO4) being produced at a particular factory in Sweden. Originally believing the material was tellurium, Berzelius eventually realized that it was actually a previously unknown element. Selenium occurs in minerals such as eucairite (CuAgSe), crooksite (CuThSe) and clausthalite (PbSe), but these minerals are too rare to use as a major source of selenium. Today, most selenium is obtained as a byproduct of refining copper.
From the Greek word Selene, moon. Discovered by Berzelius in 1817, who found it associated with tellurium (named for the earth).
Elemental selenium has several allotropes. The most familiar macroscopic forms are red amorphous selenium and gray trigonal selenium, a brittle, metallic-looking solid that is the most stable form at ordinary conditions. Black vitreous selenium can form by rapid cooling from the melt.
Selenium has been used in photocells, light meters, rectifiers, and xerographic photoreceptors, although many of these applications have been reduced by silicon and organic photoconductors. It is still used to decolorize or color glass, producing ruby-red glasses and counteracting green iron tints. Small additions improve machinability in some copper and steel alloys. Selenium compounds are used in pigments, rubber vulcanization chemistry, antifungal shampoos, and as reagents in organic synthesis.
Selenium's resistance to the flow of electricity is greatly affected by the amount of light shining on it. The brighter the light, the better selenium conducts electricity. This property has made selenium useful in devices that respond to the intensity of light, such as electric eyes, photo cells, light meters for cameras and copiers. Selenium can also produce electricity directly from sunlight and is used in solar cells. Selenium is also a semiconductor and is used in some types of solid-state electronics as well as in rectifiers, devices which convert alternating current electricity into direct current electricity. In addition to its use in electrical devices, selenium is also used to make a ruby-red color in glasses and enamels, as a photographic toner and as an additive to stainless steel.
Selenium forms few inorganic compounds, none of which are commercially important. They include selenious acid (H2SeO3), selenium dichloride (SeCl2) and selenium oxychloride (SeOCl2).
Selenium is used in Xerography for reproducing and copying documents, letters, etc. It is used by the glass industry to decolorize glass and to make ruby-colored glasses and enamels. It is also used as a photographic toner, and as an additive to stainless steel.
Isotopes in Earth/Planetary Science
Molecules, atoms, and ions of the stable isotopes of selenium possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. There are measureable variations in the isotopic abundances of selenium in natural terrestrial materials (Fig. IUPAC.34.1).
Isotopes in Industry
75Se (with a half-life of 120 days) is used for X-ray radiography of welds to visualize welds and ensure that each weld is appropriate for its purpose [274] P. Hayward, D. Currie. “Radiography of welds using seleniuim 75, Ir 192 and x-rays”, in Asia-Pacific Conference on NDT, Auckland, New Zealand (2006)..
Isotopes in Medicine
75Se-selenomethionine (organic compound that combines to form proteins, found in Brazil nuts and soybeans) has been used to study the production of digestive enzymes (biological catalysts that accelerates chemical reactions) [275] A. C. Colella, F. Pigorini. Br. J. Radiol.40, 662 (1967).. Selenium stable isotopes are used in metabolic studies to monitor selenium intake and output [276] C. A. Swanson, D. C. Reamer, C. Veillon, J. C. King, O. A. Levander. Am. J. Clin. Nutr.38, 169 (1983)., [277] Public Health Service Agency for Toxic Substances and Disease Registry. Toxicological Profile for Selenium, U.S. Department of Health and Human Services (2014), Feb. 26; http://www.atsdr.cdc.gov/ToxProfiles/tp92.pdf..
Isotopes Used as a Source of Radioactive Isotope(s)
77Se and 78Se are used to produce the therapeutic radioisotope 77Br via the 77Se (n, p) 77Br and the 78Se (n, 2p) 77Br reactions, respectively. 80Se is used to produce 80mBr via the reaction 80Se (n, p) 80mBr. The m the superscript of 80mBr indicates a metastable state of the isotope.
Selenium occurs in oxidation states from −2 to +6, with −2, +4, and +6 especially important. Hydrogen selenide, H₂Se, is a highly toxic gas and the selenium analogue of hydrogen sulfide. Selenium dioxide, SeO₂, is a useful oxidizing reagent and forms selenous acid, H₂SeO₃, in water. Selenates such as sodium selenate, Na₂SeO₄, resemble sulfates chemically but are biologically more active. Metal selenides are important semiconductors, including cadmium selenide, CdSe, and copper indium gallium selenide used in thin-film photovoltaics.
See more information at the Selenium compound page.
Selenium is essential in trace amounts, but excess intake can cause selenosis, with gastrointestinal effects, hair and nail changes, and a garlic-like breath odor from volatile metabolites. Elemental selenium is less acutely hazardous than many soluble selenite and selenate salts, but dust exposure should be controlled. Hydrogen selenide, H₂Se, is extremely poisonous, and industrial selenium fumes or aerosols require strict ventilation and monitoring.
Hydrogen selenide at a concentration of 1.5 ppm is intolerable to man. Selenium occurs in some solid in amounts sufficient to produce serious effects on animals feeding on plants, such as locoweed, grown in such soils. Exposure to selenium compounds (as Se) in air should not exceed 0.2 mg/m3 (8-hour time-weighted average - 40-hour week).
Selenium is widely dispersed in sulfide ores, sedimentary rocks, soils, and waters, usually at low concentrations. Weathering and irrigation can mobilize selenate and selenite, which are taken up by plants and can bioaccumulate in food webs. Some plants tolerate and concentrate selenium, while many others show toxicity only where soils or drainage waters are selenium-rich. Microorganisms can reduce soluble selenium species to less mobile elemental selenium or volatile methylated forms.
Selenium is not normally mined as a primary product. Most commercial supply is recovered as a by-product from anode slimes produced during electrolytic refining of copper, with smaller links to other nonferrous metal processing. Demand is spread across glass manufacture, metallurgy, chemicals, electronics, and thin-film photovoltaic materials, so supply depends strongly on copper refining rather than direct selenium ore availability. Substitution has reduced some older electrical uses, but recovery remains economically useful because selenium is concentrated in refinery residues. Recycling occurs mainly through industrial scrap and process residues rather than consumer products.
Obtained from lead, copper and nickel refining. Conducts electricity when struck by light.
Selenium is a relatively uncommon cosmic element compared with lighter chalcogens. Its stable isotopes are produced mainly by neutron-capture processes in evolved stars and supernova-related environments, with contributions from both slow and rapid neutron capture. In planetary materials it behaves partly as a chalcophile element, tending to associate with sulfides rather than silicate minerals.
- Gray selenium conducts electricity better when illuminated.
- Selenium can replace sulfur in some amino acids, forming selenocysteine and selenomethionine.
- The smell associated with selenium exposure often comes from volatile methylated selenium compounds.
- Selenium was identified in residues from sulfuric acid manufacture.
- Some selenium-rich plants can poison grazing animals on naturally seleniferous soils.
- Cadmium selenide quantum dots can emit size-tunable visible light.
画像
性質
物理的性質
- 原子半径（経験値）
- 115 pm 全元素の原子半径（経験値）を比較 →
- 共有結合半径
- 120 pm 全元素の共有結合半径を比較 →
- ファンデルワールス半径
- 190 pm 全元素のファンデルワールス半径を比較 →
- 金属半径
- 117 pm 全元素の金属半径を比較 →
- 密度
- 4809 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.0165 L/mol
- 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
- 220.5 °C 全元素の融点を比較 →
- 沸点
- 684.85 °C 全元素の沸点を比較 →
- 熱伝導率
- 0.52 W/(m·K) 全元素の熱伝導率を比較 →
- 比熱容量
- 0.321 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 25.363 J/(mol·K) 全元素のモル熱容量を比較 →
- 結晶構造
- 六方最密充填構造 全元素の結晶構造を比較 →
化学的性質
- 電気陰性度（Pauling）
- 2.55 全元素の電気陰性度（Pauling）を比較 →
- 電気陰性度（Allen）
- 2.424
- 電子親和力
- 2.0206 eV
- 第1イオン化エネルギー
- 9.752368 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
- 21.196073 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
- 31.697109 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
- 42.947148 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
- 68.300235 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- −2, −1, 0, +1, +2, +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 →
- 同素体
- ["gray", "vitreous"]
- 電子配置
- [Ar] 4s2 3d10 4p4
熱力学的性質
- 臨界点（温度）
- 1493 °C
- 融解熱
- 0.0693372 eV 全元素の融解熱を比較 →
- 蒸発熱
- 0.27258123 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 2.352697 eV
- 原子化熱
- 2.352697 eV
- 原子化エンタルピー
- 2.35477 eV
原子核
- 陽子数
- 34 全元素の陽子数を比較 →
- 中性子数
- 46 全元素の中性子数を比較 →
- 既知の同位体
- 33 全元素の既知の同位体を比較 →
- 安定同位体
- 4 全元素の安定同位体を比較 →
- 最も安定な同位体
- Se-80
- 発見年
- 1817
存在度
- 存在度（地殻）
- 0.05 mg/kg 全元素の存在度（地殻）を比較 →
- 存在度（海洋）
- 2 × 10−4 mg/L 全元素の存在度（海洋）を比較 →
結晶構造
- 格子定数a
- 436 pm
電子構造
- 各電子殻の電子数
- 2, 8, 18, 6 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7782-49-2 全元素のCAS登録番号を比較 →
- 項記号
- 3P2
- InChI
- InChI=1S/Se
- InChI Key
- BUGBHKTXTAQXES-UHFFFAOYSA-N
電子配置 測定値
Se: 3d¹⁰ 4s² 4p⁴[Ar] 3d¹⁰ 4s² 4p⁴1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁴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
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 |
|---|---|---|---|
| 76 安定 | 75.919213704 ± 0.000000017 | 9.3700% | 安定 |
| 77 安定 | 76.919914154 ± 0.000000067 | 7.6300% | 安定 |
| 78 安定 | 77.91730928 ± 0.0000002 | 23.7700% | 安定 |
| 80 安定 | 79.9165218 ± 0.0000013 | 49.6100% | 安定 |
相／状態
理由: 融点（220.5 °C）より195.5 °C低い
模式図、実際の縮尺とは異なります
相転移点
相転移エネルギー
融点で1 molを融解させるのに必要なエネルギー
沸点で1 molを蒸発させるのに必要なエネルギー
昇華点で1 molを昇華させるのに必要なエネルギー
密度
標準条件下
標準条件下
詳細
原子スペクトル
全34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。
スペクトル線データの収録状況 ?
| イオン | 電荷 | スペクトル線の総数 | 遷移確率 | 準位の表記 |
|---|---|---|---|---|
| Se I | 0 | 138 | 0 | 0 |
| Se II | +1 | 39 | 0 | 0 |
| Se III | +2 | 39 | 0 | 0 |
| Se IV | +3 | 22 | 0 | 0 |
| Se V | +4 | 17 | 0 | 0 |
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Se I | 0 | 173 |
| Se II | +1 | 78 |
| Se III | +2 | 53 |
| Se IV | +3 | 29 |
| Se V | +4 | 15 |
| Se VI | +5 | 7 |
| Se VII | +6 | 45 |
| Se VIII | +7 | 37 |
| Se IX | +8 | 2 |
| Se X | +9 | 2 |
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| -2 | 6 | データなし | 198 pm |
| +4 | 6 | データなし | 50 pm |
| +6 | 4 | データなし | 28.000000000000004 pm |
| +6 | 6 | データなし | 42 pm |
化合物
同位体 (4)
Naturally selenium contains six stable isotopes. Fifteen other isotopes have been characterized. The element is a member of the sulfur family and resembles sulfur both in its various forms and in its compounds.
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 76 安定 | 75.919213704 ± 0.000000017 | 9.3700% ± 0.2900% | 安定 | stable | |
| 77 安定 | 76.919914154 ± 0.000000067 | 7.6300% ± 0.1600% | 安定 | stable | |
| 78 安定 | 77.91730928 ± 0.0000002 | 23.7700% ± 0.2800% | 安定 | stable | |
| 80 安定 | 79.9165218 ± 0.0000013 | 49.6100% ± 0.4100% | 安定 | stable |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 116 pm
- 共有結合半径（Pyykkö、二重結合）
- 107 pm
- 共有結合半径（Pyykkö、三重結合）
- 107 pm
- 共有結合半径（Bragg）
- 117 pm
ファンデルワールス半径
- Bondi
- 190 pm
- Batsanov
- 190 pm
- Alvarez
- 182 pm
- UFF
- 420.5 pm
- MM3
- 229 pm
- Dreiding
- 403 pm
原子半径と金属半径
- 原子半径（Rahm）
- 224 pm
- 金属半径（C12）
- 140 pm
番号付けの尺度
- Mendeleev
- 101
- Pettifor
- 93
- Glawe
- 95
電気陰性度の尺度
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 6
- Robles–Bartolotti
- 5
分極率と分散
- 双極子分極率
- 28.9 a.u.
- 双極子分極率（不確かさ）
- 1 a.u.
- C₆
- 210 Ha·Bohr6
- C₆ (Gould–Bučko)
- 233 Ha·Bohr6
供給リスクと経済性
- 生産集中度
- 35
- 相対供給リスク
- 7
- 埋蔵量の分布
- 22
- 政治的安定性（最大生産国）
- 77
- 政治的安定性（最大埋蔵国）
- 18
相転移と同素体
| 転移温度 | 453.15 K |
| 沸点 | 958.15 K |
| 臨界点（温度） | 1766.15 K |
| 融点 | 493.95 K |
| 沸点 | 958.15 K |
| 臨界点（温度） | 1766.15 K |
| 臨界点（圧力） | 27.2 MPa |
酸化数の分類
専門参考データ
遮蔽定数 (8)
| n | 軌道 | σ |
|---|---|---|
| 1 | s | 0.7378 |
| 2 | p | 3.9348 |
| 2 | s | 9.1116 |
| 3 | d | 15.523 |
| 3 | p | 15.295 |
| 3 | s | 14.5966 |
| 4 | p | 25.7128 |
| 4 | s | 24.2424 |
結晶半径の詳細 (4)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| -2 | VI | 184 | Pauling's (1960) crystal radius, | |
| 4 | VI | 64 | Ahrens (1952) ionic radius, | |
| 6 | IV | 42 | ||
| 6 | VI | 56 | calculated, |
同位体の崩壊形式 (52)
| 同位体 | モード | 強度 |
|---|---|---|
| 63 | B+ | 100% |
| 63 | B+p | 89% |
| 63 | 2p | 0.5% |
| 64 | B+ | — |
| 64 | B+p | — |
| 65 | B+ | 100% |
| 65 | B+p | 87% |
| 66 | B+ | 100% |
| 66 | B+p | — |
| 67 | B+ | 100% |
X線散乱因子 (506)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 5.20241 |
| 10.1617 | — | 5.36005 |
| 10.3261 | — | 5.52247 |
| 10.4931 | — | 5.63017 |
| 10.6628 | — | 5.66221 |
| 10.8353 | — | 5.69443 |
| 11.0106 | — | 5.71762 |
| 11.1886 | — | 5.72709 |
| 11.3696 | — | 5.73659 |
| 11.5535 | — | 5.7461 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
5×10-2 milligrams per kilogram
参考文献 (1)
- [5] Selenium https://education.jlab.org/itselemental/ele034.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
2×10-4 milligrams per liter
参考文献 (1)
- [5] Selenium https://education.jlab.org/itselemental/ele034.html
Production
Production of this element (from raw materials or other compounds containing the element).
Selenium is found in a few rare minerals such as crooksite and clausthalite. In years past it has been obtained from flue dusts remaining from processing copper sulfide ores, but the anode metal from electrolytic copper refineries now provide the source of most of the world's selenium. Selenium is recovered by roasting the mud with soda or sulfuric acid, or by smelting them with soda and niter.
参考文献 (1)
- [6] Selenium https://periodic.lanl.gov/34.shtml
参考文献
(9)
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 Selenium.
The element property data was retrieved from publications.