Tantalum (Ta)
transition-metalSolid
標準原子量
180.94788 u電子配置
[Xe] 6s2 4f14 5d3融点
3016.85 °C沸点
5457.85 °C密度
1.64e+4 kg/m³酸化数
−3, −1, 0, +1, +2, +3, +4, +5電気陰性度（Pauling）
1.5第1イオン化エネルギー
7.549571 eV発見年
1802原子半径
145 pm詳細
Tantalum is a dense, refractory transition metal in group 5, closely associated geologically and chemically with niobium. It is noted for exceptional resistance to corrosion, a very high melting point, and the stable, high-permittivity oxide film that forms on its surface. Most natural tantalum is ¹⁸¹Ta, with a small contribution from the long-lived nuclear isomer ¹⁸⁰ᵐTa. Its chemistry is dominated by the +5 oxidation state.
Tantalum is a gray, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide. Alkalis attack it only slowly. At high temperatures, tantalum becomes much more reactive. The element has a melting point exceeded only by tungsten and rhenium. Tantalum is used to make a variety of alloys with desirable properties such as high melting point, high strength, good ductility, etc. Tantalum has a good "gettering" ability at high temperatures, and tantalum oxide films are stable and have good rectifying and dielectric properties.
The name derives from the Greek mythological character Tantalus who was banished to Hades, the region of lost souls where he was placed up to his chin in water, which receded whenever he tried to drink it, and under branches of fruit, which drew back whenever he tried to pick their fruit. This name was selected because of the insolubility of tantalum in acids; thus, when placed in the midst of acids, it is incapable of taking any of them up. Tantalum was discovered by the Swedish chemist and mineralogist Anders- Gustav Ekeberg in 1802.
Tantalum was discovered by Anders Gustaf Ekenberg, a Swedish chemist, in 1802 in minerals obtained from Ytterby, Sweden. Many scientists believed that he had only discovered an allotrope of niobium, an element that is chemically similar to tantalum. The issue was finally settled in 1866 when, Jean Charles Galissard de Marignac, a Swiss chemist, proved that tantalum and niobium were two distinct elements. The first relatively pure samples of tantalum were first produced in 1907. Today, tantalum is primarily obtained from the minerals columbite ((Fe, Mn, Mg)(Nb, Ta)2O6), tantalite ((Fe, Mn)(Ta, Nb)2O6) and euxenite ((Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)2O6).
Named after Tantalos, a Greek a mythological character, father of Niobe. Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum were identical elements until Rowe in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids. The early investigators only isolated the impure metal. The first relatively pure ductile tantalum was produced by von Bolton in 1903. Tantalum occurs principally in the mineral columbite-tantalite.
Pure tantalum is a hard, heavy, lustrous metal with a gray to blue-gray metallic surface. It is ductile when sufficiently pure but becomes less workable when contaminated by oxygen, nitrogen, hydrogen, or carbon. A thin oxide film passivates the surface in air.
Tantalum is widely used in solid electrolytic capacitors, where a porous metal anode and a thin tantalum pentoxide dielectric provide high capacitance per volume. It is also used in corrosion-resistant chemical equipment, heat exchangers, surgical implants, and high-temperature furnace parts. Tantalum carbide is important in hard materials, and tantalum additions improve some nickel- and cobalt-base superalloys. Because it absorbs little from body fluids and is corrosion resistant, the metal has had longstanding biomedical applications.
Tantalum is a strong, ductile metal that is nearly immune to chemical attack at room temperatures. It can be drawn into a fine wire that is used to evaporate metals, such as aluminum. It has a high melting point and is frequently used as a substitute for platinum, which is more expensive. Tantalum is used to make components for chemical plants, nuclear power plants, airplanes and missiles. Tantalum does not react with bodily fluids and is used to make surgical equipment. Tantalum also does not irritate the body and is used to make surgical sutures as well as implants, such as artificial joints and cranial plates. Tantalum is alloyed with steel to increase steel's ductility, strength and melting point.
Tantalum pentoxide (Ta2O5), one of tantalum's compounds, is a dielectric material and is used to make capacitors. It is also used to make a glass with a high index of refraction that is used in camera lenses. A composite consisting of tantalum carbide (TaC) and graphite is one of the hardest materials known and is used on the cutting edges of high-speed machine tools.
Scientists at Los Alamos have produced a tantalum carbide graphite composite material, which is said to be one of the hardest materials ever made. The compound has a melting point of 3738°C. Tantalum is used to make electrolytic capacitors and vacuum furnace parts, which account for about 60% of its use. The metal is also widely used to fabricate chemical process equipment, nuclear reactors, aircraft, and missile parts. Tantalum is completely immune to body liquids and is a nonirritating material. It has, therefore, found wide use in making surgical appliances. Tantalum oxide is used to make special glass with high index of refraction for camera lenses. The metal has many other uses.
Isotopes in Medicine
178 Ta (with a half-life of 9.3 min) is used in medical studies, such as first-pass radionuclide angiography of mice, to better understand cardiovascular disease. Radionuclide angiography uses a pinhole lens fitted to a high-speed multiwire proportional camera and a n(178W)/n(178Ta) amount-ratio generator for minimally invasive quantification of murine ventricular (heart) functions (Fig. IUPAC.73.1) [506] J. Lacy, T. Nanavaty, D. Dai, N. Nayak, N. Haynes, C. Martin. J. Nucl. Cardiol.8, 171 (2001)., [507] C. J. Hartley, G. E. Taffet, A. K. Reddy, M. L. Entman, L. H. Michael. ILAR J.43, 147 (2002).. The multiwire gamma camera has a 178Ta generator incorporated in its housing, and it provides portable and laboratory ventricular function assessments for cardiovascular patients [507] C. J. Hartley, G. E. Taffet, A. K. Reddy, M. L. Entman, L. H. Michael. ILAR J.43, 147 (2002)., [508] J. L. Lacy, A. D. LeBlanc, J. W. Babich, M. W. Bungo, L. A. Latson, R. M. Lewis, L. R. Poliner, R. H. Jones, P. C. Johnson. J. Nucl. Med.25, 1003 (1984).. Intravenous injections of 178Ta are used in gated equilibrium blood pool imaging [509] R. A. Wilson, S. Y. Kopiwoda, R. J. Callahan, R. H. Moore, C. A. Boucher, H. Manspeaker, F. P. Castronovo, H. W. Strauss. Eur. J. Nucl. Med. Mol. Imaging13, 82 (1987).. 183Ta (with a half-life of 5.1 days) has potential for use in radionuclide pharmaceuticals and as a tracer for toxicity studies of ecosystems [510] N. Shigeta, R. M. Lambrecht, H. Matsuoka, A. Osa, M. Koizumi, K. Kobayashi, M. Izumo, K. Hashimoto, T. Sekine. Appl. Radiat. Isot.47, 171 (1996)..
Isotopes Used as a Source of Radioactive Isotope(s)
181Ta is used to produce 178W, which decays to 178Ta via the reaction 181Ta (p, 4 n) 178W, which is followed by a subsequent electron capture decay reaction of 178W to finally yield 178Ta. 178Ta is important for medical studies as noted in Section 4.73.1.
Tantalum forms strongly oxophilic compounds and is most stable in the +5 oxidation state. Tantalum pentoxide, Ta₂O₅, is the most important oxide and forms the dielectric film used in capacitors. Tantalum pentachloride, TaCl₅, is a volatile chloride used in synthesis and deposition chemistry. Tantalates contain TaO₆ octahedra in many minerals and ceramic materials. Lower oxidation states exist in halides and cluster compounds, but they are less common in ordinary aqueous chemistry. Tantalum carbide, TaC, is an extremely hard refractory ceramic.
See more information at the Tantalum compound page.
Massive tantalum metal is generally of low chemical toxicity and is valued for biocompatibility, but fine powder can burn and should be treated as a combustible metal dust. Soluble tantalum compounds are uncommon but should not be assumed harmless. Processing hazards often come from associated acids, fluorides, chlorides, and fine particulates rather than from the bulk metal itself. Natural tantalum is only very weakly radioactive because of trace ¹⁸⁰ᵐTa.
Tantalum occurs in resistant oxide minerals and is not abundant in surface waters. Weathering can move small amounts in heavy-mineral sediments, while much remains in insoluble phases. It has no known essential biological role. Environmental concerns are usually linked to mining, mineral concentration, tailings, and the handling of associated elements rather than to high mobility of tantalum ions in natural waters.
Tantalum is produced mainly from tantalite- and columbite-bearing ores, from complex lithium-cesium-tantalum pegmatites, and as a by-product of tin or lithium mineral processing. Separation from niobium is a central refining step because the two elements have similar chemistry. Demand is strongly influenced by electronics, especially capacitors, but superalloys, carbides, and corrosion-resistant equipment also matter. Supply can be constrained by ore concentration, co-production relationships, conflict-mineral controls, and the need for specialized refining. Recycling from capacitor scrap and superalloy residues contributes but does not fully replace mined supply.
Tantalum ores are found in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire, and Canada.
Tantalum is a rare heavy element in the cosmos. Its stable and long-lived isotopes are made mainly by neutron-capture processes in earlier generations of stars, with contributions from slow and rapid capture pathways. In planetary materials it is lithophile and refractory, so it concentrates in silicate reservoirs and resists volatilization during high-temperature condensation.
- Tantalum and niobium are so similar chemically that their separation shaped much of their early metallurgy.
- ¹⁸⁰ᵐTa is the rarest naturally occurring long-lived nuclear isomer known.
- The dielectric layer in tantalum capacitors is grown directly from the metal surface.
- Tantalum resists many acids but is attacked by hydrofluoric acid and fluoride-containing mixtures.
- Its name refers to Tantalus, reflecting the early difficulty of dissolving its oxide.
画像
性質
物理的性質
- 原子半径（経験値）
- 145 pm 全元素の原子半径（経験値）を比較 →
- 共有結合半径
- 170 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
- 217 pm 全元素のファンデルワールス半径を比較 →
- 金属半径
- 134 pm 全元素の金属半径を比較 →
- 密度
- 1.64 × 104 kg/m³ 全元素の密度を比較 →
- モル体積
- 0.0109 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
- 3016.85 °C 全元素の融点を比較 →
- 沸点
- 5457.85 °C 全元素の沸点を比較 →
- 熱伝導率
- 57.5 W/(m·K) 全元素の熱伝導率を比較 →
- 比熱容量
- 0.14 J/(g·K) 全元素の比熱容量を比較 →
- モル熱容量
- 25.36 J/(mol·K) 全元素のモル熱容量を比較 →
- 結晶構造
- 体心立方構造 全元素の結晶構造を比較 →
化学的性質
- 電気陰性度（Pauling）
- 1.5 全元素の電気陰性度（Pauling）を比較 →
- 電気陰性度（Allen）
- 1.34
- 電子親和力
- 0.322 eV
- 第1イオン化エネルギー
- 7.549571 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
- 16.200056 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
- 23.10008 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
- 35.00012 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
- 48.272166 eV 全元素の第5イオン化エネルギーを比較 →
- 酸化数
- −3, −1, 0, +1, +2, +3, +4, +5 全元素の酸化数を比較 →
- 価電子
- 5 全元素の価電子を比較 →
- 電子配置
- [Xe] 6s2 4f14 5d3
熱力学的性質
- 融解熱
- 0.37902265 eV 全元素の融解熱を比較 →
- 蒸発熱
- 7.804322 eV 全元素の蒸発熱を比較 →
- 昇華熱
- 8.104887 eV
- 原子化熱
- 8.104887 eV
- 原子化エンタルピー
- 8.104887 eV
原子核
- 陽子数
- 73 全元素の陽子数を比較 →
- 中性子数
- 108 全元素の中性子数を比較 →
- 既知の同位体
- 40 全元素の既知の同位体を比較 →
- 安定同位体
- 1 全元素の安定同位体を比較 →
- 最も安定な同位体
- Ta-181
- 発見年
- 1802
存在度
- 存在度（地殻）
- 2 mg/kg 全元素の存在度（地殻）を比較 →
- 存在度（海洋）
- 2 × 10−6 mg/L 全元素の存在度（海洋）を比較 →
結晶構造
- 格子定数a
- 331 pm
電子構造
- 各電子殻の電子数
- 2, 8, 18, 32, 11, 2 全元素の各電子殻の電子数を比較 →
識別子
- CAS登録番号
- 7440-25-7 全元素のCAS登録番号を比較 →
- 項記号
- 4F3/2
- InChI
- InChI=1S/Ta
- InChI Key
- GUVRBAGPIYLISA-UHFFFAOYSA-N
電子配置 測定値
Ta: 4f¹⁴ 5d³ 6s²[Xe] 4f¹⁴ 5d³ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d³ 6s²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 |
|---|---|---|---|
| 181 安定 | 180.9479958 ± 0.000002 | 99.9880% | 安定 |
相／状態
理由: 融点（3016.85 °C）より2991.8 °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
原子スペクトル
全73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 |
|---|---|---|---|---|
| Ta I | 0 | 526 | 200 | 510 |
| Ta II | +1 | 141 | 0 | 13 |
| Ta IV | +3 | 83 | 0 | 0 |
| Ta V | +4 | 12 | 0 | 0 |
準位データの収録状況 ?
| イオン | 電荷 | 準位 |
|---|---|---|
| Ta I | 0 | 301 |
| Ta II | +1 | 134 |
| Ta III | +2 | 2 |
| Ta IV | +3 | 2 |
| Ta V | +4 | 2 |
| Ta VI | +5 | 2 |
| Ta VII | +6 | 2 |
| Ta VIII | +7 | 2 |
| Ta IX | +8 | 2 |
| Ta X | +9 | 2 |
イオン半径
| 電荷 | 配位 | スピン | 半径 |
|---|---|---|---|
| +3 | 6 | データなし | 72 pm |
| +4 | 6 | データなし | 68 pm |
| +5 | 6 | データなし | 64 pm |
| +5 | 7 | データなし | 69 pm |
| +5 | 8 | データなし | 74 pm |
化合物
同位体 (1)
| 質量数 | 原子質量（u） | 天然存在比 | 半減期 | 崩壊形式 | |
|---|---|---|---|---|---|
| 181 安定 | 180.9479958 ± 0.000002 | 99.9880% ± 0.0003% | 安定 | stable |
詳細な性質
共有結合半径（詳細）
- 共有結合半径（Pyykkö）
- 146 pm
- 共有結合半径（Pyykkö、二重結合）
- 126 pm
- 共有結合半径（Pyykkö、三重結合）
- 119 pm
ファンデルワールス半径
- Batsanov
- 220 pm
- Alvarez
- 253 pm
- UFF
- 317 pm
- MM3
- 243 pm
原子半径と金属半径
- 原子半径（Rahm）
- 258 pm
- 金属半径（C12）
- 146 pm
番号付けの尺度
- Mendeleev
- 49
- Pettifor
- 53
- Glawe
- 52
電気陰性度の尺度
- Ghosh
- 0
- Miedema
- 4
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
分極率と分散
- 双極子分極率
- 74 a.u.
- 双極子分極率（不確かさ）
- 20 a.u.
- C₆ (Gould–Bučko)
- 887 Ha·Bohr6
ミーデマパラメータ
- ミーデマモル体積
- 10.81 cm3/mol
- ミーデマ電子密度
- 4
供給リスクと経済性
- 生産集中度
- 25
- 相対供給リスク
- 7
- 埋蔵量の分布
- 54
- 政治的安定性（最大生産国）
- 48
- 政治的安定性（最大埋蔵国）
- 48
相転移と同素体
| 融点 | 3290.15 K |
| 沸点 | 5728.15 K |
酸化数の分類
専門参考データ
遮蔽定数 (14)
| n | 軌道 | σ |
|---|---|---|
| 1 | s | 1.4163 |
| 2 | p | 4.4136 |
| 2 | s | 19.0702 |
| 3 | d | 13.5589 |
| 3 | p | 21.1996 |
| 3 | s | 21.9085 |
| 4 | d | 36.676 |
| 4 | f | 39.5296 |
| 4 | p | 34.2652 |
| 4 | s | 33.2412 |
結晶半径の詳細 (5)
| 電荷 | CN | スピン | rcrystal (pm) | 由来 |
|---|---|---|---|---|
| 3 | VI | 86 | estimated, | |
| 4 | VI | 82 | estimated, | |
| 5 | VI | 78 | ||
| 5 | VII | 83 | ||
| 5 | VIII | 88 |
同位体の崩壊形式 (52)
| 同位体 | モード | 強度 |
|---|---|---|
| 155 | p | 100% |
| 156 | p | 71% |
| 156 | B+ | 29% |
| 157 | A | 96.6% |
| 157 | p | 3.4% |
| 157 | B+ | — |
| 158 | A | 100% |
| 158 | B+ | — |
| 159 | B+ | 66% |
| 159 | A | 34% |
X線散乱因子 (716)
| エネルギー (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 3.16064 |
| 10.1152 | — | 3.23709 |
| 10.2317 | — | 3.31539 |
| 10.3496 | — | 3.39558 |
| 10.4688 | — | 3.47772 |
| 10.5894 | — | 3.56683 |
| 10.7114 | — | 3.65875 |
| 10.8348 | — | 3.75304 |
| 10.9596 | — | 3.84976 |
| 11.0859 | — | 3.94897 |
追加データ
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.0 milligrams per kilogram
参考文献 (1)
- [5] Tantalum https://education.jlab.org/itselemental/ele073.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
2×10-6 milligrams per liter
参考文献 (1)
- [5] Tantalum https://education.jlab.org/itselemental/ele073.html
Sources
Sources of this element.
Tantalum ores are found in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire, and Canada.
参考文献 (1)
- [6] Tantalum https://periodic.lanl.gov/73.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Separation of tantalum from niobium requires several complicated steps. Several methods are used to commercially produce the element, including electrolysis of molten potassium fluorotantalate, reduction of potassium fluorotantalate with sodium, or reacting tantalum carbide with tantalum oxide. Twenty five isotopes of tantalum are known to exist. Natural tantalum contains two isotopes.
参考文献 (1)
- [6] Tantalum https://periodic.lanl.gov/73.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 Tantalum.
The element property data was retrieved from publications.